Building a Pinwheel Skeleton Clock

Discussion in 'Clock Construction' started by Allan Wolff, Nov 12, 2010.

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  1. Ed Buc

    Ed Buc Registered User

    Apr 1, 2010
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    Re: Plates and Pillars for the Pinwheel Skeleton Clock

    I agree, there is nothing cooler than holding a group of screws you made. When I made the NAWCC project clock, I made my own screws from drill rod, using a graver, and slotted them with a jewelers saw! They were not perfect, but I think small imperfections kind of work well in an self-built clock - you don't want it to look too perfect!

    I like your idea of using a dremel buff. I had been holding them is a pin vice and using a large buff on my grinder.

    I noticed you coated your screws with wax. You are not going to blue them?
     
  2. Allan Wolff

    Allan Wolff Moderator
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    Re: Plates and Pillars for the Pinwheel Skeleton Clock

    As Ed noted, the screws were not blued. They were left silver on the original clock and I thought they looked very nice. In fact, none of the parts appear to have been blued; even the hands look black (but I will blue mine.) If I decide to blue the screws later, I should be able to give them a quick dip in acetone to remove the wax and then proceed with heat blueing.

    Now that we have the plates, the fusee stop works can be fabricated. The fusee stop works is a safety device that prevents the fusee from being wound to the point where the cable runs off the end of the fusee. This could cut the cable which would be disastrous with a fully wound spring.

    The fusee stop mounts on the small end of the fusee and provides a protruding tab that catches on the fusee iron when the cable pulls it into position. No special machining is required and I just marked it out on a piece of 1/16” thick brass sheet. The holes are drilled first while there is plenty of material available to clamp the brass in the drill press. The outline is then cut out with a jewelers saw and the edges are smoothed with a file. The bevel on the tab is also filed to shape. The completed stop is shown in the first photo. The stop is not mounted to the fusee just yet since its position will be determined by test fitting after the stop assembly is complete.

    The fusee iron mount is made from a short length of 3/8” brass rod. The rod is held on the lathe in a collet. The end is faced and drilled to a depth of ¼” and then tapped to 6-32. This is the bottom of the mount. The mount is then removed, reversed in the collet and parted off to a length of 1/2". The end is rounded with a profile tool in the same manner as the plate screw heads. An index plate is installed to hold the lathe headstock and a 1/16" wide slot is cut to a depth of 5/16” with a slitting saw. The part is rotated 90 degrees and a #53 hole is cross drilled for the pivot pin with the milling spindle. The part is then removed from the lathe and a small hole for the spring wire is located below the slot with a very sharp center punch. The mount is then placed in a vise at a 65-degree angle and the hole is drilled with a #78 drill bit. Small drill bits can be used in a bench drill press if the chuck will close down on the bit and run out is minimal. Alternately, a small, homemade drill press as shown in the second photo works much better when drilling small holes. The table moves up to feed the work to the bit. The spindle assembly is a Fordom rotary handheld unit driven by a DC motor from a surplus battery-powered drill. An adjustable power supply provides a speed range of approximately 2000-20,000 RPM.

    A short length of .015” music wire serves as the fusee iron return spring. This spring moves the fusee iron out of the way from the fusee stop when the cable is not fully wound. The wire may be cut to length at this time, but it will not be fastened to the mount until after final assembly so it does not become damaged during polishing. The fusee mount and fusee iron are shown in the third photo.

    The fusee mount will be located on the back of the front plate to the right of the fusee arbor as shown in the fourth photo. Note the section of plate beneath the fusee arbor should be cut out at this time to provide access to the fusee stop area. A hole is drilled in the plate at the location shown to pass a 6-32 screw. Dimensions of the fusee iron are determined by partially assembling the fusee stop, fusee and spring barrel between the plates. A section of cable is strung between the barrel and the fusee and measurements are taken so the fusee stop and hook of the fusee iron are perpendicular as shown in the fourth photo. The distance from the fusee stop to the cable is also measured. These dimensions are laid out on a piece of 1/16” mild steel plate and then cut and filed to shape. The iron, mount and spring are temporarily assembled using a drill bit or wire as a temporary pin. The location of where the spring contacts the iron as marked as shown in the fifth photo. A shallow groove is cut at this location with a dremel cutoff tool to prevent the spring from slipping off of the edge of the iron. This slot can be seen in the third photo.

    The iron is then placed in its mount and the cable positioned as shown in the fourth photo. The fusee is rotated, allowing the cable to track the groove to simulate the clock being wound. The fusee stop is located so that the hook just clears the stop on one pass and just catches the hook on the next pass as the cable reaches the end of the fusee. Several attempts may be required to find the correct location. The fusee stop location is marked on the fusee and the hole locations are transferred to the end of the fusee. These holes are drilled and tapped 0-80.

    A 1/2" length of 1/16” diameter steel rod or music wire is used for the fusee iron pivot pin. The hole in the mount is enlarged with a broach for a snug fit of the pin. Do not install the pin at this time; it will be installed after polishing. 90675.jpg 90676.jpg 90677.jpg 90678.jpg 90679.jpg
     
  3. carloclock

    carloclock Registered User

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    Re: Plates and Pillars for the Pinwheel Skeleton Clock

    I completely do not agree :)
    Even when working on a piece by hand , I guess that every effort should be made to get is as perfect as possible.

    " it is made by hands but it looks like it was made by a machine" : it is this what makes a clockmaker bursting with joy....:)

    Cordialità.
    Carlo
     
  4. Allan Wolff

    Allan Wolff Moderator
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    Re: Plates and Pillars for the Pinwheel Skeleton Clock

    The maintaining pawl prevents the maintaining wheel from rotating backwards when the clock is wound.

    The maintaining pawl rides across the ratchet teeth of the maintaining wheel and drops into place by its own weight. The ratchet teeth are rather shallow and have a slight undercut. Therefore, the maintaining pawl must be positioned so there are not any forces that would tend to push the pawl out of the ratchet tooth. At the same time, the pawl should not be so far from the wheel that excessive force is created on the arbor. Similar to the mainspring barrel click, a CAD drawing is used to determine the geometry. Previously created scaled drawings of a section of the plate, maintaining wheel, great wheel and the pawl are combined in the first photo. Thick red construction lines are drawn through the center of the pawl and perpendicular to the point of the pawl. The pawl and these construction lines are then maneuvered into place such that the perpendicular line falls close to and slightly to the right of the center of the maintaining wheel arbor as shown. If the line falls to the left of center, there will be an upward force on the pawl that will tend to push it out of the ratchet tooth. This would happen if the pawl is too long or the arbor is located too close to the maintaining wheel. If the pawl is too short or the arbor is located too far from the maintaining wheel, the line will fall farther to the right. Although this would create more force to hold the pawl in the ratchet tooth, unnecessary force would also be created on the arbor, possibly bending it.

    The outline of the pawl is marked on a sheet of 1/8” thick mild steel. The arbor hole is drilled and reamed to 1/8” and then outline is cut with a jeweler’s saw. The pawl is then filed and sanded to a 600-grit finish. The contact point should have a sharp edge to prevent slippage in the maintaining wheel teeth.

    The arbor is simply a length of 1/8” diameter music wire cut to a length of 2.625”. Note that this length is not long enough to pass completely through the plates; and that is intended. Rather than reduce the ends to form pivots or install collars on each end to hold the arbor in place, the pivot holes will not be drilled through. This provides a strong pivot without an unsightly hole on the outside of the plates. More on this later; first the arbor location must be determined.

    A light scribe mark is made on the inside of each plate at the location shown in the first photo. Remember to offset in the opposite direction when locating the front plate, as it will be reversed from the figure. The second photo shows the location of the pivot holes. The through holes shown above the pivot holes where used for reference and will serve as access holes for cutting out the inner sections of the plates with the jeweler’s saw. A plate is clamped in the drill press and the depth stop is set to drill a 1/8” deep hole with a 1/8” diameter bit. You may wish to test the setting on a piece of scrap to make sure the drill tip does not penetrate the outside of the plate. The drill bit is replaced with a 1/8” end mill. The drill press is turned by hand and feed into the drilled hole until the bottom is cut flat. This operation is repeated for the other plate. The plates, pillars and maintaining pawl arbor are assembled to verify the arbor has approximately 1/64” end shake and the arbor spins freely in the holes. It is not necessary to burnish or polish the pivots or holes since the arbor does not rotate.

    The maintaining pawl can now be installed on its arbor between the plates with the fusee, maintaining wheel and great wheel in place as shown in the third photo. The pawl should drop smoothly into each ratchet tooth as the maintaining wheel is rotated counterclockwise. Verify that the pawl stays securely in the tooth when the wheel is rotated clockwise. The pawl will be fastened to the arbor with Loctite after final polishing is complete.

    This completes the miscellaneous parts for the plates. In the next thread, construction will begin on the motions works. 91563.jpg 91564.jpg 91565.jpg
     
  5. Allan Wolff

    Allan Wolff Moderator
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    Motion Works for the Pinwheel Skeleton Clock

    The motion works often goes unnoticed but provides several critical functions. The most obvious purpose is to divide twelve rotations of the minute hand into 1 rotation of the hour hand. It also provides a clutch mechanism that allows the hands to be moved to set the time without disrupting the time train. And in this clock, it also divides 4 rotations of the third wheel into one rotation of the minute hand.

    This clock uses the traditional English design of developing the 12:1 gear reduction with a single set of gears coupled together with two intermediate wheels of the same tooth count. The motion works uses 0.5 module wheels and pinions to keep the size of the wheels small. An 8-leaf pinion drives a 96-tooth wheel to obtain the 12:1 reduction. The pinion and wheel have a combined pitch circle diameter (PCD) of 2.047 inches. Since the intermediate wheels must have the same combined PCD. Two 52-tooth wheels have a combined PCD of 2.048 inches, which is entirely sufficient. It is also convenient that 52 is divisible by 4 and can be used to reduce the drive train as required. Unfortunately, the resulting 13-leaf pinion is rather nonstandard but only a minor inconvenience. I will be the first to admit that this motion works is very unorthodox, but it gets the job done.

    A side view CAD drawing helps to understand how the parts fit together. From this drawing, each component can be detailed. Here is the general theory of how it works. The third arbor extends through the front plate and has a 13-tooth pinion mounted on it. This pinion makes 4 revolutions per hour in a counterclockwise direction. It meshes with the lower 52-tooth wheel(shown in blue), causing it to rotate once per hour in a clockwise direction. The spring (curved purple-colored part between the two blue wheels) provides friction to drive the upper blue wheel and the minute pipe assembly shown in green. The minute hand will mount on the end of this pipe. The upper blue 52-tooth wheel drives the 52-tooth intermediate wheel along with its 8-pin pinion shown on the far right in purple, in a counterclockwise direction. The pinion drives the 96-tooth hour wheel (shown in tan) clockwise one revolution every twelve hours. The hour hand will mount on the hour hand pipe, also shown in tan. The copper colored part shown in the lower left is the bridge which provides support for the pipes.

    When constructing the motion works, many of the dimensions depend on the fit of another part. The order of construction provided here will provide the parts in the order needed to build the next. 91694.jpg
     
  6. RJSoftware

    RJSoftware Registered User

    Apr 15, 2005
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    Re: Motion Works for the Pinwheel Skeleton Clock

    If one was building a wood clock. Home made wood gears. What would be the simplest and durable form of a clutch?

    The watch uses friction fit of the cannon pinion. But in wood that I think would not be durable.

    RJ
     
  7. Allan Wolff

    Allan Wolff Moderator
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    Re: Motion Works for the Pinwheel Skeleton Clock

    You might try posting this question in the Wood Movement Clocks forum.
     
  8. cmnewcomer

    cmnewcomer Registered User

    Mar 24, 2009
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    Re: Cutting Pinions for the Pinwheel Skeleton Clock

    Allan,

    I've been tooling up to build clocks for about 20 years now and have been looking for suppliers of pinion rod. The problem is that I can only find 12L14 for the 6 and 8 leaf pinion rod I need. Do you have a source for pinion rod in high carbon steel such as drill rod?

    The first clock I built I used pinion cutters from PP Thorton but I am no longer cutting gears with the epicycloidal form but rather the involute form. I realize that that involute form is not traditional but that's what my Grandfather used so I am following his design. I have ordered cutters from Russell, Holbrook, & Henderson but they will not come from about 8 weeks or so. Even if I get the cutters, I would much rather purchase pinion rod if there is a supplier that uses drill rod.

    Thanks in advance for any advice.

    Best Regards.

    Carl
     
  9. Allan Wolff

    Allan Wolff Moderator
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    Re: Cutting Pinions for the Pinwheel Skeleton Clock

    Carl,
    Apparently they stopped making epicycloidal pinion wire years ago. However, since you are using involute gears, you may be in luck. Here is a link to Stock Drive Products. http://www.sdp-si.com/eStore/CoverPg/Gears.htm
    They have pinion wire from 6 to 60 teeth, 14.5 and 20 degree pressure angle, 24 to 64 DP, in brass and carbon steel. I do not know if the carbon steel is similar to drill rod, but it might be worth a call or email to ask them.
     
  10. cmnewcomer

    cmnewcomer Registered User

    Mar 24, 2009
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    Re: Cutting Pinions for the Pinwheel Skeleton Clock

    Allan,

    Thanks for the reply. I've contacted them and others but it's all drawn and 12L14 seems to be what they all use unfortunately. I did try to get one company to draw 1144 but the said they wouldn't do it. 1144 can't be hardened but it's the most durable of the low carbon steels and has the highest carbon content of the steels that can't be hardened.

    I didn't realize you cut your pinions and fell on that post this mornings so it looks like I will also continue to cut my own pinions.

    Best Regards.

    Carl
     
  11. Allan Wolff

    Allan Wolff Moderator
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    Re: Motion Works for the Pinwheel Skeleton Clock

    Construction of the motion works begins with the three pipes that stack in a nested fashion, one inside the other.

    The hour pipe is made first. As the name implies, the hour pipe will carry the hour hand. A length of 1/2” diameter brass rod centered in the 4-jaw chuck. The end is faced and a light cleanup pass is made along the outside. The diameter is then reduced to .438” for a length of 3/8”, then reduced again to .375” for a length of 1/4”. The corners are cleaned out with a graver or sharp-edge file. The pipe is then drilled to 19/64” to a depth just over 1/2” and then bored to a final diameter of .313”. A reamer can also be used, but boring will ensure the inside is concentric with the outside. The bottom shoulder is cut to a diameter of .375” with a parting tool and the surfaces that will be exposed (.500” and .438” diameter sections) are sanded to a 600-grit finish. Finally, the pipe is parted off to a total length of .500”. The hour pipe is shown in the upper left of the first photo.

    The bridge pipe will be mounted to a fixed bracket and provides support for the hour and minute pipes. the hour pipe fits over the outside of the bridge pipe and the minute pipe fits inside. Machining of the bridge pipe is very similar to the hour pipe with a few exceptions. The upper portion of the pipe should be machined for a length of 1/2" for a nice slip fit inside the hour pipe. The bottom shoulder is cut to a diameter of .313" with the parting tool. The .250" hole through the center will likely need to be reamed unless a very small boring bar is available, so care should be taken to ensure the drill and reamer run straight. The bridge pipe is shown in the center of the first photo.

    The minute pipe is made up of two sections, one brass and the other steel. Steel is used to reduce the potential for wear from the clutch and to provide additional strength to support a small pivot wire. This construction technique may be a bit unorthodox, but it allows the components to be easily installed and removed from the clock plate without having to bother with friction fits or set screws. The lower section is made slightly over size first and then brought to its final dimensions when mated to the upper section. A length of 3/8” mild steel rod is faced and then reduced to .322". The end is further reduced to .235" for a length of 3/8" and then reduced again to .138" for a length of 1/4". The smallest diameter section is then threaded #6-32. The die is then reversed to chase the thread all the way to the shoulder. This piece is then parted off to a total length of .431”. This part will be machined to its final dimensions after the upper section is complete.
    The upper portion of the minute pipe is machined for a nice slip fit inside the bridge pipe for a length of 3/4". The end is drilled #56 approximately 3/8” deep and tapped #0-80. Flats are milled at the end where the minute hand will be mounted. The flats should measure .156” across.

    The upper section is then reversed in the lathe and mounted in a 1/4” collet. The end is faced to provide the total length of .910” for the part. The end is then drilled approximately 3/8” deep and tapped #6-32.

    The lower section is now screwed into upper section still mounted in the lathe. It is tightened with soft jaw pliers to make sure the faces make good contact. It may be necessary to chamfer the threaded hole of the upper section to accommodate any partially completed threads on the lower section. The lower section is faced, removing only enough material to make it run true. Take light cuts to bring the larger steel shoulder to its final diameter of .312”. A parting tool is used to true up the inner shoulder to a diameter of .225”. A hole is drilled #55, (.052”) to a depth of .18”. Both steel shoulders and the face are sanded to a 600-grit finish or better.

    The end of a 1/2” length of .055” music wire is slightly tapered until it fits approximately .1” into the hole with finger pressure. The wire is tapped into final position with a small hammer. Loctite can be used if the drill made the hole oversized. The wire is trimmed to .188” length and verified that it runs straight. The wire is then sanded and polished to 1500-grit finish or better as this will be a rotating pivot. It is not necessary to burnish the wire since the pressure on the motion works is negligible. the completed minute pipe is shown on the right of the photo.

    This completes the work on the pipes. They are shown assembled in the second photo. Note that the minute pipe sticks out a little farther than the other pipes. This will provide clearance between the hour and minute hands. Very little of these parts will be visible after final assembly and the surfaces that do show will be polished at a later time.

    The bridge will be made next. 92251.jpg 92252.jpg
     
  12. Allan Wolff

    Allan Wolff Moderator
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    Re: Motion Works for the Pinwheel Skeleton Clock

    The bridge is made from a piece of 1/2" square brass bar. It can easily be cut out with a saw, but this was an excellent opportunity to try out the new (vintage 1953) Benchmaster mill that I recently restored. The mill is shown in the third photo.

    The brass bar is clamped in the milling vise and a pass is taken across the end to square it up. Multiple passes are then made across the top until the thickness is reduced to 1/8” for a length of 7/8” as shown in the first photo. Several passes are used to remove the material rather than a single heavy cut due to the amount of overhang. The stock is extended slightly and a .053” cut is taken across the top to reduce the high of the bridge to .447”. The stock is then turned upside down and several cuts are taken until the thickness of the short arm is 1/8” for a length of 1/2” as shown in the second photo.

    The stock is turned over once again a .1” deep cut is taken down each side to reduce its width to .3” except for the last ½” of the long arm. The bridge is then removed from the stock with a jeweler’s saw and the rounded end of the long arm is filed to shape.

    A .144” diameter hole is drilled in the short arm with a #27 drill bit to pass a 6-32 screw. This screw was made previously at the same time as the fuse iron mount screw and plate screws. The .3125” hole in the long arm should be reamed for a close fit of the bridge pipe. The bridge is filed all over and sanded to a 600-grit finish. The completed bridge was shown with the pipes in the previous post.

    It is now time to move on to the wheels and pinions. 92801.jpg 92802.jpg 92803.jpg
     
  13. Allan Wolff

    Allan Wolff Moderator
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    Re: Motion Works for the Pinwheel Skeleton Clock

    Construction of the 96-tooth hour wheel is identical to the time train wheels except the teeth are smaller, .5 module. The center hole is bored as shown in the first photo for a tight fit on the hour hub. This method described in J.M. Huckabee’s book “Top 300 Trade Secrets of a Master Clockmaker,” uses a block of wood in which a pocket is trepanned into the face. Since the face and pocket are cut in place, they run perfectly true. I used the same wood block that was used to make the great wheel which explains the fancy pattern around the edge! The wheel is a friction fit into the pocket and light cuts are taken while boring the center hole to the required size. The wheel will be fastened to the hour pipe with Loctite after final polishing. Traditionally, the wheel would be staked in place, but Loctite allows the wheel to be precisely placed and eliminates any possibility of damaging the wheel or hour pipe.

    The 52-tooth intermediate wheels can all be cut at the same time. The initial center hole of all three wheels should be .191” to fit the intermediate pinion. One wheel is then bored to .225” to fit the lower minute pipe and the other wheel is bored to .250” to fit the upper minute pipe. The wheels on the upper minute pipe and intermediate pinion will be fastened with Loctite after polishing. The wheel for the lower minute pipe will be a slip fit to allow it to rotate as part of the clutch. The intermediate wheels are not crossed out. However, the wheel mounted to the intermediate pinion and minute pipe wheel will be visible behind the dial so they are given a concave surface to add a little visual appeal. The wheels are shown in the second photo.

    The canon spring fits between the two minute wheels and provides just enough friction to keep the wheels from slipping yet allows the minute hand to easily turn when setting the time. A piece of .015” thick brass is hammered to work-harden it and make it springy. The part is marked out and drilled before cutting the outside shape to allow extra material to clamp while drilling. The hole is drilled #2 and then filed for a slip fit on the lower section of the minute pipe. The outline is then cut with tin snips and filed to its final shape. All surfaces of the spring are smoothed with sand paper and then curved as shown in the third photo. The spring is installed on the arbor between the minute pipe wheels as shown in the fourth photo. The curve of the spring is adjusted so the lower wheel slips easily. 92997.jpg 92998.jpg 92999.jpg 93000.jpg
     
  14. Allan Wolff

    Allan Wolff Moderator
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    Re: Motion Works for the Pinwheel Skeleton Clock

    The drive pinion mounts on the front of the plate on the third wheel arbor. It is made from a length of 3/8” brass rod. The outside diameter of the rod is reduced to .288” and 13 teeth are cut with a fly cutter. Cutter dimensions for a 13-tooth pinion are not commonly found but a cutter for a 12-tooth pinion will work just fine. The teeth should be 1/16” thick to match the intermediate wheels. The center hole is center drilled and reamed to .106” for a slip fit on the third wheel arbor. The diameter of the hub section is reduced to .170” for a length of .188” and then cross drilled with a #60 drill bit (.040”) through the hub for a taper pin that will be used to fasten the drive pinion to the arbor. The pinion is shown temporarily mounted on the arbor in the first photo. The arbor will be cross drilled and trimmed to length in a later step. The hub and face of the pinion are sanded to a 600-grit finish and parted off to a length of .250”.

    The intermediate pinion is made from 1/4” mild steel rod. A 1” length is installed in a collet with approximately 3/4” protruding. The end is faced and the diameter is reduced to .191” for a length of .440”.

    A tiny .5 module fly cutter will not likely survive cutting a steel pinion even when using mild steel, and a multi-tooth cutter takes quite a bit of time to make. Instead, a rather unorthodox method is used to cut the intermediate pinion teeth. Similar to the time train pinions, 8 slots are cut to a depth of .054” with a .025” thick slitting saw. The saw is advanced 3/8” after it first contacts the edge of the pinion. The teeth are then brought to their final shape using the same Cratex abrasive wheels that were used to polish the time train pinions. Only light pressure is needed to shape the teeth as the Cratex wheels cut the mild steel very easily. Purists may take exception to forming teeth in this way and I admit that they are not perfect. However, there is so little force present in the motion works that virtually any shape of tooth will work.

    After the teeth are formed, the center hole is drilled to a diameter of .055”. The exposed surfaces are sanded to a 600-grit finish and the pinion is parted off to a length of .534”. The finished pinions are shown in the second photo. The third photo shows the intermediate wheel installed on the pinion. This should be a friction fit, but a little Loctite can be used if the fit is too loose.

    The intermediate arbor will be made next and it is the final part needed to complete the motion works. 93378.jpg 93379.jpg 93380.jpg
     
  15. Allan Wolff

    Allan Wolff Moderator
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    Re: Motion Works for the Pinwheel Skeleton Clock

    The intermediate arbor is made from two pieces. This will simplify several aspects of construction.

    The base is made from a section of 3/8” mild steel. After facing the end, the diameter is reduced to .112” for a length of .188” and threaded #4-40. The die is reversed to chase the threads all the way to the shoulder. A graver may also be used to clean out the corner to allow the shoulder to sit flat when the arbor is installed on the plate. The center hole is drilled .055" to approximately 3/8” deep.

    The shoulder is machined to a hex shape so the arbor can be installed on the plate with a standard 1/4” socket or wrench. This is accomplished using the same setup used to cut the winding arbors for the fusee and mainspring. The arbor shoulder diameter is reduced to .289” for approximately 1/8”. The flats are then cut using the setup shown in the first photo. An index plate mounted on the other end of the headstock provides the 6 divisions required. Note a drill chuck is used to hold the end mill since the collet assembly was in use holding the work piece. Guess I need to buy another collet set. The distance across the flats should be verified that it measures .250”.

    The arbor is parted off so the hex shoulder is approximately 1/8” high. This is slightly greater than the CAD dimensions call for to allow the height of the intermediate wheel to be adjusted later if necessary.

    The sides of the hex shoulder are sanded and polished to remove the tooling marks from the end mill. This can be done by hand, but it is much easier with the setup shown in the second photo. This is simply 400-grit sandpaper glued to an aluminum disk and will provide a mirror finish when spun at high speed using light pressure.

    .055" diameter music wire is used for the intermediate arbor shaft. Drill rod can also be used if the required diameter is available. A 1.25” length is chucked in the lathe and the end is rounded with a Dremel grinding wheel while the wire is slowly rotated. Approximately 1” of the wire is then polished to a 1500-grit or better finish. The wire is then removed from the lathe and cross-drilled with a .025” hole approximately .060” from the rounded end. It will be necessary to use a carbide drill bit to penetrate the music wire and carbide bits in this size break very easily. A micro-sized drill press is invaluable when drilling holes this small. If drill rod is used, it can be drilled with regular high speed steel drill bits. The wire will be trimmed to length in a future step.

    A washer is required between the taper pin and the intermediate pinion. A short length of 1/4” brass rod is placed in a collet and drilled to .055”. The outside diameter is reduced to .2” for a short distance and then parted off to a thickness of .015”. The washer is then sanded to a 600-grit finish.

    A taper pin is required that will fit the .025” cross-hole of the music wire shaft. A pin can be purchased or it can easily be made from mild steel wire ground to a taper with a Dremel cutoff wheel. The intermediate arbor parts along with the intermediate pinion are shown in the third photo.

    Next time, the motion works will be assembled and adjusted. 93807.jpg 93808.jpg 93809.jpg
     
  16. Allan Wolff

    Allan Wolff Moderator
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    Re: Motion Works for the Pinwheel Skeleton Clock

    Now that all of the parts are complete, the motion works assembly can be fitted to the plate. Several adjustments and dimensions will be determined by test fitting the parts.

    The spacing between the third arbor and the minute pipe pivot is determined by installing an intermediate wheel and the drive pinion in the depthing tool. This dimension is transferred to the front plate placing the minute pipe pivot between the 3rd and 4th arbors. The hole is drilled undersize and broached it to its final diameter.

    Next the bridge location is determined. The plates and pillars are assembled with the 3rd arbor installed. The drive pinion is placed on the arbor and the intermediate wheels and spring are installed on the minute pipe and the assembly is inserted in the hole just drilled. The bridge pipe is placed in the bridge and slipped over the minute pipe. While holding the short arm of the bridge against the plate near the 4th arbor, verify there is a very small amount of end shake between the minute and bridge pipes. At the same time, verify the position of the bridge allows the minute pipe arbor to turn freely and the lower intermediate wheel meshes properly with the drive pinion. The location of the bridge mounting hole is then transferred to the front plate. The drive pinion is positioned on the 3rd arbor so the teeth are the same height as the lower intermediate wheel as shown in the first photo. The position of the drive pinion mounting hole is transferred to the 3rd arbor. The plates are disassembled and the 3rd arbor drilled with a #60 bit for a taper pin. The end of the arbor is then trimmed so it is flush with the drive pinion.

    The bridge mounting hole is drilled in the plate with a #36 bit and the hole is tapped #6-32.

    To mount the intermediate arbor, the spacing between the wheels on the minute pipe and the intermediate wheel is determined with the depthing tool. This measurement is transferred to the appropriate location on the front plate. The hole is drilled and tapped #4-40. The location of the intermediate arbor is shown in the second photo. It should be noted that the plate was skeletonized after the intermediate arbor was located just in case it needed to be moved from its calculated location.

    The intermediate pinion and wheel are installed as shown in the third photo to align height of the wheels. Since the hex shoulder was initially left thick, the intermediate wheel can be lowered to the correct alignment by removing material from the top of the hex shoulder. When the wheels align, the top of the hex shoulder is polished since it will be a bearing surface.
    With the hex base finished, the shaft length can now be determined. The end of the shaft and hex base hole are cleaned with acetone. The intermediate pinion, washer and taper pin are assembled on the shaft as shown in the last photo of the previous post. Loctite is applied to the end of the shaft and it is inserted into the hex base. After the Loctite sets, the extra length of shaft protruding through the base can be trimmed off with a Dremel cutoff wheel. Use care not to get the parts hot or the Loctite bond will be broken.

    The third photo shows the entire motion works assembly with the exception of the hour pipe and wheel. This completes the motion works for now. The bridge pipe and fixed intermediate wheels will be permanently attached after final polishing.

    Next up is the pendulum assembly. 94576.jpg 94577.jpg 94580.jpg
     
  17. Allan Wolff

    Allan Wolff Moderator
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    Pendulum for the Pinwheel Skeleton Clock

    This clock is designed for a half-second beat rate requiring an effective pendulum length of 9.78 inches. For proper appearances, the overall length of the pendulum will be approximately 14 inches. To achieve the correct beat rate, the pendulum assembly will be constructed with some weight in the rod and the bob weight will be adjusted to obtain the correct rate via direct measurement.

    Although a simple, straight pendulum rod would serve our purpose, a more complex design similar to the original clock is chosen for visual appeal. Standard mild steel and brass are used with the components silver soldered together. I did not use Invar or other forms of temperature compensation since the temperature in most houses today does not vary more than a few degrees over the entire year.

    Most of the components are rather simple to make, so I will only go into detail on the more complex pieces. The parts of the pendulum rod are shown in the first photo and the completed pendulum is shown in the second photo. The upper and lower sections are constructed of 1/8” thick mild steel plate. They are easily rough cut with a jewelers saw and filed to their final dimensions. One end of the upper section is cross-drilled with a #65 bit for a pin to hold the suspension spring. A .010” wide slot for the spring is then cut in the same end. A fine 2/0 jewelers saw blade provides the correct width of cut. The slot for the crutch pin will be located by test fitting the parts together in a later step. The lower section is drilled in one end with a #44 bit to receive the rating rod.

    The two center sections are also made from mild steel like the previous sections, except they are 1/16” thick.

    The brass connectors will be made in the next update. 95109.jpg 95110.jpg
     
  18. Allan Wolff

    Allan Wolff Moderator
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    Re: Pendulum for the Pinwheel Skeleton Clock

    The first photo shows a closeup of the connectors. Two are required. The connectors are made from scraps of 3/16” brass left over from the plates. Each piece is cut out with a jeweler’s saw and filed to shape. A recess is milled into each connector to accept the upper or lower and center sections. A 1/4” end mill is used to cut the wide slot for the upper and lower sections and a 1/8” end mill is used to cut the slot for the center sections. These parts will be silver soldered together in a later step.

    For the rating rod, a length of 1/8” mild steel rod is reduced to .086” diameter. The material is held in a collet and machined 1/2” at a time close to the collet to reduce flexing. After 1.75” of rod has been reduced, it is sanded and polished and then threaded #2-56 for a length of 1”. The unthreaded end is installed in the lower section of the pendulum as shown in the second photo and held in place with Loctite.

    The rating nut can be made in a variety of shapes for decorative purposes. The nut is also shown in the second photo and has a simple 1/4” radius and knurl. A fine knurl should be used to complement the small size of the nut. The third photo shows the scissor-type tool used to cut the knurl. The nut is then drilled with a #50 bit and tapped 2-56. The radius and face of the nut are finished to 600-grit before parting off.

    The suspension spring is made from .003” thick blue spring steel. Rather than purchase a large quantity of spring steel, this spring was simply removed from a factory-made replacement suspension rod. Small brass squares are snipped from a .032” thick sheet, drilled #52 and soldered on each side to one end of the spring as shown in the fourth photo. A stainless steel 0-80 screw is used to align the parts. The alligator clip vise holds the assembly and also presses the parts together when the solder melts. Solder does not stick to stainless steel very well and the 0-80 alignment screw is simply unscrewed after the solder sets up. The blocks will be filed to the correct thickness to fit the slot in the suspension bracket. The spring is trimmed to length and a new hole is punched as shown in the fifth photo. The spring is difficult to drill, but a hole can easily be punched in the thin material using a small punch and plate. This hole will be used to attach the suspension spring to the pendulum with a small pin.

    The pendulum will be assembled next. 95510.jpg 95511.jpg 95512.jpg 95513.jpg 95514.jpg
     
  19. Re: Pendulum for the Pinwheel Skeleton Clock

    Very nice work, Allan.
    I've been reading the forum for a while but only posting recently. I haven't come to the 'Clock Construction' section often.
    I see I'm missing a lot of good work in your threads here. I'll be reading them!
    Again, good job.

    Dean
     
  20. Scottie-TX

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    Re: Pendulum for the Pinwheel Skeleton Clock

    So, then, the regulating nut at bottom is for coarse adjustment and the slotted sliding weight for fine adjustment?
     
  21. Allan Wolff

    Allan Wolff Moderator
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    Re: Pendulum for the Pinwheel Skeleton Clock

    Dean,
    Thank you for the positive comments. It is always nice to know someone enjoys reading about this project.

    Scottie,
    On precision pendulums, the upper weight is typically the fine adjustment as you suggest. Unfortunately there is very little precision in this pendulum design. The sliding weight is simply a means of making a long pendulum beat faster than one with all of the weight in the bob. For this clock, appearance is very important and a short pendulum just doesn't look right. I will go over how the pendulum rate is adjusted in a future post. For now, just know that the upper weight will be the course adjustment and the fine adjustment will be done by adjusting the bob with the rating nut.

    Now we need to assemble the pendulum rod.
    If you look closely at the connectors in the first photo of the previous post, you will see that corners are left rounded on one of the pockets where it was cut with the end mill. Rather than attempt to square them up, it is easier to round the corners of the center sections with a file. These can be see on the left side of the first photo of the first post. Silver solder is used to assemble the parts. Flux is brushed on the area to be soldered and each piece is tinned with just enough solder to coat the surface. Try to avoid globs of solder, as these will make it more difficult to align the parts. Excess solder can be filed off if necessary after the part cools.
    Heat for soldering is applied with a small butane torch like the one shown in the upper right of the first photo. It provides a much smaller flame and better temperature control than a typical hardware store propane torch. I highly recommend it for silver soldering and heating small parts. Search the Internet for "Blazer GB2001" for more information.

    Notice in the photo that firebricks are used to provide a heat resistant work surface and a scrap strip of metal helps align the parts in a straight line.

    After the parts are tinned, they are placed together, aligned and joined by equally heating both parts until the solder melts. It is often helpful to push the parts together by applying pressure with a screwdriver or piece of scrap metal. I seem to have better luck soldering parts together by tinning them in this way rather than fluxing the assembled parts and applying the solder to the joint.

    The suspension bracket base is made from another scrap of 3/16” thick brass. Dimensions of the outline are determined by matching the base to the clock plate. The outline can be left oversize and brought to its final shape when the plates are finished. The base needs to be located so that the suspension spring flex point lines up with the pallet arbor. A 6-32 screw that we made earlier is used to fasten the base to the plate.

    The suspension bracket post is made from 1/4” square brass. One end is turned for a slip fit into the larger hole of the base. The slot for the suspension spring is cut 3/8” deep with a slitting saw as shown in the second photo. Scraps of brass are used to hold the post in the milling vise. The scraps are sacrificed and cut along with the post. After the slot is cut, the holes are drilled for the suspension spring screw. One hole is drilled #56 and tapped 0-80 while the other hole is drilled #53 to clear the screw. The blocks of the suspension spring are now filed to reduce their thickness until the assembly just slips into the post slot. The post and bracket are shown in the third photo. Note that the photo shows the post before the holes for the suspension spring were drilled. The post will be fastened to the base with Loctite after final polishing.

    Next time I will show you how I made the bob with tools and materials not normally associated with clockmaking. Stay tuned. 95812.jpg 95813.jpg 95814.jpg
     
  22. Allan Wolff

    Allan Wolff Moderator
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    Re: Pendulum for the Pinwheel Skeleton Clock

    Most bobs are formed by spinning the brass shells on the lathe, but the little Taig is not rigid enough to perform this operation. Instead, the shells are shaped by stamping.

    Two disks approximately 3 1/8” diameter are cut from 1/32” brass sheet with a jeweler’s saw. A wood form is turned on the lathe to 3" diameter and the face is rounded to a radius of 4 5/8". This radius will give each shell a 1/4" thickness, or 1/2" total thickness of the assembled bob. A 3/4” thick piece of oak or other hardwood should be used so that it will stand up to the stamping operation without deforming or splitting. I used a piece of scrap oak flooring. The remaining parts needed are shown in the first photo a piece of scrap metal the approximate size of the form, a scrap of sheetrock (also known as gypsum board or drywall) and a large hammer. I used a 10-pound sledge hammer and it was none too small for this task. The scrap metal is used to distribute the force of the hammer blow evenly across the form. The sheetrock provides a firm surface that deforms and pushes the brass around the form.

    The second photo shows the metal, form and brass shell stacked on top of the sheetrock. The stack is struck very firmly with the hammer. The brass shell takes the shape of the form as the sheetrock is dented from the force. The brass work hardens as it bends and must be annealed and stamped several times before the shell fully matches the shape of the form. I had to anneal and stamp each shell about 4 times to reach the final shape.

    After both shells are shaped, the form is remounted on the lathe and the shells are held between it and a live center as shown in the third photo. I used double-sided tape may help hold the shell to the form. Light cuts are taken around the edge to clean up the saw cuts and bring the shells to their final diameter of 3 inches.

    The shells are then rubbed with the rounded side up on sandpaper laid flat to remove any burs and provide a flat surface around the entire edge. The shells are then cut to allow the lower section of the pendulum to pass through. The rating rod is temporarily inserted into the lower section and the assembly is positioned across the center of the shells as shown in the fourth photo. A Dremel cutoff tool or files are used to remove only enough material to allow the shell edges to come together. Alternate working on each shell so the pendulum section is centered.

    Tests are required to determine if weight distribution of the pendulum assembly is correct before the shells are permanently joined. The fifth photo shows the pendulum assembly balanced on the edge of a file to locate its center of gravity. The bob is temporarily held together with tape. The center of gravity was found to be at approximately 9.5” from the flex point of the suspension spring. The center of oscillation will be somewhat lower than the center of gravity. We need the center of oscillation to be 9 7/8", so this looks promising. As a second test, the suspension bracket and pendulum assembly are mounted to the clock frame and set in motion. The number of swings appears to be approximately 120 beats per minute, but it is difficult to tell without a precision timer. A long duration test will be necessary to determine the exact rate of the pendulum. However, these tests provide an indication that the beat rate of the pendulum will be within the required range without adding any significant weight to the bob.

    Since we do not need to make any adjustments to the weight of the bob, the shells can be soldered together. The inside of each edge is fluxed and tinned with silver solder. I used the small butane torch to tin the edges. The shells are then aligned with each other and placed on the firebrick. The sixth photo shows a scrap aluminum disk that was placed under the shells to lift the bob off of the firebrick for easier access to the edge. Another piece of scrap aluminum shown in the upper right of the figure is used to press the shells together while the edge is heated with a larger propane torch; the butane torch just did not provide enough heat to make both shells hot enough to melt the solder. After the solder melts, the torch is removed while the shells are pressed together until the solder solidifies. The edge is then filed to shape. 96119.jpg 96120.jpg 96121.jpg 96122.jpg 96123.jpg 96124.jpg
     
  23. tok-tokkie

    tok-tokkie Registered User

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    Re: Pendulum for the Pinwheel Skeleton Clock

    I have made a pendulum bob & need to make another in the foreseeable future. There is much I will follow from Alan's post - especially the silver soldering advice.

    To form the brass I made an hydraulic forming rig out of some 12mm (1/2") steel I had to hand. Flat plate for the base with a 150mm ring bolted by 8 M8 bolts to the base. The brass was cut to fit just inside the bolts. The ring had a narrow (2mm?) lip at its inner edge so the brass was tightly held just there. There was a threaded hole in the base. I borrowed a hydraulic hand pump. It stretched the brass very easily & I fitted a dial gauge above the job so could measure the stretch to 0.01mm & both sides were just the same. No skill & no effort.
     
  24. Scottie-TX

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    Re: Pendulum for the Pinwheel Skeleton Clock

    I applaud you on your choice of a brass backed bob soldered together. As you know, the earliest Vienna bobs were made that way. Some are bolted together via threaded bosses soldered to back of front half. These old brass backed are the most coveted here because they are so wafer thin with no unsightly halo around the perimeter left from crimping. Nice. Sweet.
     
  25. Allan Wolff

    Allan Wolff Moderator
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    Re: Pendulum for the Pinwheel Skeleton Clock

    Adjusting the beat of a clock is often accomplished by bending the crutch. This seems a rather crude operation so I want to replace the simple crutch that was used to test the escapement with an adjustable crutch. I found several designs used on regulators, but I ended up using one of my own design. The collet made for the test escapement will be reused.

    The original crutch was only one part. Making it adjustable adds quite a bit of complication. None of the parts are complicated, there are just a lot of them. The first photo shows all of the parts and the second photo shows how it all goes together. Note the crutch has an offset to connect the arbor to the pendulum on opposite sides of the rear plate. The vertical arm needs to be long enough to allow the crutch to pass through the cutout in the rear plate with enough room to swing. The overall length of the assembly need not be exact since the pendulum slot will be positioned to match the pin on the crutch. The pin is made from music wire and is left long so it can be trimmed to length during final assembly.

    The posts are 1/32" different in length so the holes in the posts line up when the arms are attached. The longer post is drilled through to pass the 2-56 adjusting screw. The knurled top and round brass nut hold the adjuster tight around the post while allowing it to be turned. The shorter post is threaded 2-56.

    The posts are attached to the arms with 0-80 screws and washers. I made the washers, but used factory made screws. The adjuster is also made from a long 2-56 factory made screw. The head is cut off and replaced with a knurled nut Loctited in place.

    A shoulder nut is located at the pivot point of the crutch arms. It is made of mild steel to provide a bearing surface and is also threaded 0-80.

    The posts, shoulder nut and adjusting screw should be free to rotate but not so loose that they wobble. Likewise, the shoulder nut must allow the arms to pivot without any unnecessary movement. This means that the screws cannot be fully tightened and will tend to work loose. Therefore, the screws will be secured with low-strength Loctite after final adjustments and polishing are complete.

    Operation of the adjustable crutch is simple. Turning the adjuster pulls the posts closer together, moving the crutch pin to the left; or pushes the posts apart, moving the crutch pin to the right.

    With the crutch complete, we are now ready to drill the pendulum to accept the crutch pin and test the rate of the pendulum. 96734.jpg 96735.jpg
     
  26. Allan Wolff

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    Re: Pendulum for the Pinwheel Skeleton Clock

    With the crutch finished and in place, the pendulum is now attached to the suspension bracket and the location of the crutch pin is transferred to the pendulum.

    The slot for the pin does not need to be any longer than necessary. I made it 1/4” in length. Each end of the slot is drilled with a #53 bit and the center section is cut out with a jeweler’s saw. The slot is then opened up with a needle file until the .062” crutch pin just barely slides through.

    Because the section of the pendulum is rather thick, the crutch pin may bind if the pendulum twists for any reason. To reduce the chance of binding without introducing slop between the pin and slot, the slot is tapered by slightly enlarging the slot on the backside of the pendulum with a file. This allows the pin to contact the pendulum slot at a narrow point and not bind if the pendulum twists.

    Final testing of the pendulum rate can now be completed by assembling the clock and timing it over several hours. Everything will be assembled except the motion works and fusee stop mechanism. The fusee cable needs to be cut to length at this time. The proper length is determined by installing the mainspring barrel and fusee in the frame. With the fusee filled with cable, there should be approximately one full wrap remaining around the barrel. An extra inch or two of cable is added to allow for the knot at each end.

    The second pinion was previously attached with Loctite 609 to the collet. Low-strength Loctite can be used to fasten the collet to the arbor since it has no twisting force on the arbor. I use low-strength Loctite here so it can be easily disassembled for final polishing. The third and fourth pinions and collets will need to be attached to the arbor with Loctite 609 since there is too much force in these stages of the train to use low strength Loctite. These parts should be polished now before assembly. Low-strength Loctite was used to assemble the escape wheel and collets.

    Clock oil is applied to the spring barrel flanges, pivots, pallets and crutch pin. The pendulum bob is set all the way down. With the time train and pendulum assembled and all of the cable on the barrel, the mainspring barrel is wound 1.4 turns to set the preload. Remember the amount of preload was determined when the mainspring was measured to design the fusee. With the preload set, the fusee is wound 1/2 turn. This is enough to provide several hours of runtime. The pendulum is set in motion and the crutch is adjusted for an even beat.

    After allowing the pendulum to settle, we can time the clock by counting the rotations of the third arbor. As a reference point, a taper pin is installed in the third arbor where the motions works drive pinion will attach. The pin serves as a temporary hand for timing the pendulum. Each rotation should take exactly 15 minutes. Remember the motion works will divide it by 4 to drive the hour hand. I took 4 samples over a 1-hour period. The bob is then raised to its highest position and another 4 samples are taken. If the clock loses time at the lowest bob position and gains time with the bob at its highest position, no further adjustments will be needed to the pendulum.

    Unfortunately, my tests indicated a loss of 1 minute 44 seconds per hour with the bob down and a loss of 18 seconds per hour with the bob all the way up. This means the pendulum is too long to be regulated in its current configuration. The pendulum center of oscillation needs to be raised to speed up the beat rate but a short pendulum will look out of place. We need a different solution.

    Photos of the original clock show some type of weight attached near the center of the pendulum, so the original builder may have encountered the same problem. This pendulum will be corrected in the same way.

    Two steps will be taken to add weight to the upper end of the pendulum to speed up the beat rate. First, covers will be added to the back of the brass connectors. These will not add much weight, but they do give the pendulum a more finished appearance. Second, a weight assembly will be made that attaches to the center section of the pendulum. Since the center section is slotted, this weight will be adjustable with several inches of travel.

    The connector covers are made from 1/16” thick brass using the same dimensions as the original connectors. The covers are cut out slightly over size, silver soldered to the connectors and filed to shape. Use caution not to disturb the position of the previous solder joints.

    The size of the rating weight is 3/4" square to match the width of the center section of the pendulum. I hope I don't disappoint anyone when I say the size of this weight was selected completely at random. I have no formula to tell me how much weight to add to the center of a pendulum to speed it up by a specific amount. If this weight does not work, I will need to make a new one. The weight can be lengthen if necessary to provide additional weight or made smaller for less weight. I used a scrap of 3/16" thick brass that was left over from cutting out the plates. Thicker or thinner material can also be used to adjust the weight if needed. The weight is shown with the mounting stud in the first photo. I rounded the corners of the weight to add a little decorative feature. Likewise, the shape of the stud can be as simple or complex as the builder desires. I simply cut a circular detail around the face. The top section of the stud is made from 1/2" brass rod that is drilled and tapped to receive a 2-56 screw. A #4 screw would not quite fit through the pendulum slot. In order to keep from drilling through the head of the stud, the brass rod is turned around and drilled and tapped from the bottom before parting off the piece as shown in the second photo. The 2-56 screw is then fastened with Loctite and cut off to the proper length. The weight is drilled and tapped to accept the stud.

    The rating weight is installed in the middle of the center section as shown in the third photo and a second set of readings are taken. The clock now loses 18 seconds per hour with the bob at its lowest setting and gains 53 seconds per hour at the highest setting. This shows that somewhere within this range of bob settings, the clock will keep accurate time. The rating weight can also be raised or lowered to adjust the beat rate. Refer back to the first post in this thread for a photo of the completed pendulum.

    I will start a new thread for the dial and its associated components. 97191.jpg 97192.jpg 97193.jpg
     
  27. Allan Wolff

    Allan Wolff Moderator
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    #77 Allan Wolff, Jul 31, 2011
    Last edited: Jul 31, 2011
    Dial and Hands for the Pinwheel Skeleton Clock

    The dial assembly consists of the hands, a dial pan supported by 3 pillars and the dial itself. Although only a few parts are involved, they require a substantial amount of effort to produce. The first photo is of the original clock to give you an idea of the end result. As you can see, the dial is silvered and surrounded by a scalloped ring (the pan) which adds a decorative detail.

    The dial pan supports the dial and has a curved edge that adds visual depth and stiffens it against bending. If you have a large lathe, metal spinning would be the best way to curve the edge of the dial pan. My Taig lathe is just too small for spinning metal this large or this thick. Instead I will use a form to shape the dial pan. A plywood form consisting of two disks is constructed. Each disk is approximately 1 inch thick, built up from several layers of plywood cut slightly oversize to allow the form to be turned to its final dimension. The larger disk is mounted to the lathe faceplate, turned to a diameter of 6” and faced to provide a surface that runs true. The shoulder is rounded to a 1/2” radius. The smaller disk is then centered, attached to the larger disk with 4 wood screws and turned to size. The screw holes are located so they fall in a cut away portion of the dial. A template of the dial like that shown in the second photo is printed to scale to locate these holes. A disk is cut from 1/16” thick brass and sandwiched between the two forms. The holes in the small form are used as a drilling jig as shown in the third photo. The drill bit in the center serves to align the parts. The assembly is then remounted in the lathe and the brass disk is turned to a diameter of 5.8 inches as shown in the fourth photo. The black marks make it easy to reassemble the form and brass disk. Note the larger form on the left has the curved shoulder.

    The entire assembly is then removed from the lathe. The face plate is also removed from the back of the larger disk. The assembly is placed on a solid surface such as a concrete floor. Using a hammer and wood block as shown in the fifth photo, the brass disk is shaped over the curved edge of the larger disk. The smaller form keeps the center of the dial pan flat while the edge is hammered into shape. As you can see, I used my foot to hold the assembly from moving from the hammer blows. I also used my foot to rotate the assembly after each blow as I worked around the pan. As the brass bends it will work harden, becoming springy and difficult to bend. When this occurs, the disk will need to be removed from the jig and annealed by heating it to a dull red color, just like we did with the pendulum bob. I had to anneal the dial pan twice before it would fully conform to the curved edge.

    Next time I will show how the scallops are cut. 98542.jpg 98543.jpg 98544.jpg 98545.jpg 98546.jpg
     
  28. Re: Dial and Hands for the Pinwheel Skeleton Clock

    Excellent writing and instruction, Allan. Amazing, the work that can be done on this lathe when a good deal of ingenuity is involved.
    Your progress continues to impress.
     
  29. Raynerd

    Raynerd Registered User

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    Re: Dial and Hands for the Pinwheel Skeleton Clock

    Thanks for posting Allan, very interesting and great work!

    Chris
     
  30. Allan Wolff

    Allan Wolff Moderator
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    Re: Dial and Hands for the Pinwheel Skeleton Clock

    The scallops are cut on the mill or drill press with the configuration shown in the first photo. A 1-3/16” hole saw is used to cut the brass. The brass cuts nicely with the hole saw running about 600 rpm. A rotary table would be the best tool for indexing the dial pan. Since I do not have one, an index plate is fastened to the back of the large wood disk and bolted through the center to the milling table. A small rod is bent to form an index pin and the straight end is clamped to the milling table. The assembly is then indexed to cut 20 scallops. The center bolt is loosened turn turn the assembly to the next position and then retightened before making the next cut. The lower wood disk is sacrificed during this operation as it provides support for the dial pan. Similar to cutting wheel teeth, the first two cuts should be made shallow and the assembly advanced towards the cutter, repeating the cuts until the two scallops come to a point. The remaining scallops can then be cut.

    The assembly is removed from the mill and the index plate and small wood disk are removed from the assembly. The face plate is then reinstalled on the back of the large disk. The dial pan is fastened to the large disk and this assembly is remounted on the lathe. The edge of the pan is "eyeballed in" and the disk is adjusted on the face plate until it runs reasonably true. A dial indicator is positioned approximately 2.4 inches from the center and the face of the dial pan is trued by adjusting the fastening screws. The face needs to run within 2-3 thousandths of true.

    A section of the dial pan is now trepanned to receive the dial. The outer diameter if the trepanned area is precisely 5 inches and the inner diameter is approximately 4 inches. Only very light cuts can be taken to prevent chatter. The final depth of the trepanned area should be .032” measured at the outer edge. This will allow the dial to fit flush in the recessed area. This measurement can be done visually by using a small piece of .032” brass as a gauge. Use a graver or sharp pointed tool to square the outer corner of the recessed area. The center hole is enlarged to 3/8” with a boring tool.The second photo shows the dial pan after the recessed area has been cut. The dial pan is now removed from the wood disk.

    Next time we will drill the mounting holes and make the dial pillars. 99094.jpg 99095.jpg
     
  31. Allan Wolff

    Allan Wolff Moderator
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    Re: Dial and Hands for the Pinwheel Skeleton Clock

    The mounting screws for the dial pan are next located on the front plate. A compass is set to a radius of 2.41” and marks are made on the front plate from the motion works pivot to the locations shown in the first photo. This will position the dial pan screws inside the trepanned area with a little clearance between the screw head and the trepanned edge. The holes are drilled in the front plate with a # 50 bit and tapped 2-56.

    The motion works bridge and hour pipe are then installed on the front plate to serve as a guide in centering the dial pan. This operation was shown in second photo of the previous post. (I guess I got the photos out of order, but I wanted to shown the trepan work on the last post.) The mounting hole locations are transferred from the front plate to the dial pan and countersunk so a flat head machine screw is flush or slightly recessed. Due to the thin material in this area of the dial pan (1/32"), some material may be removed from the head of the screw to obtain the clearance needed for the dial to sit flush.

    The center of the dial pan can now be removed. The pan is remounted on the large wood form on the lathe. A plunge cut is made 2 inches from the center (4 inch diameter) with a pointed lathe tool. This diameter is not critical. When the cut is almost through the dial pan, the lathe is stopped and the center section is snapped out by hand. If the cut is made all the way through, the dial pan may be damaged when it breaks loose. The sharp edge is removed and finished with a file. The second photo shows the completed dial pan.

    Now for the dial pillars. The outside shape of the dial pillars roughly matches the plate pillars. This is a simple design and the builder can be creative and make them as fancy as desired. The pillars serve as spacers to hold the dial pan away from the front plate. They .7" long and are drilled through with a #42 bit to clear a 2-56 screw. The completed pillars are shown in the third photo. It may be necessary to provide a flat area on the back of the dial pan if the pillars fall on the curved outer surface. If this occurs, a flat area is made by centering a 1/4” end mill over the hole and removing only enough material to form a complete circle around the hole as shown in the fourth photo.

    The dial will be made next. 99687.jpg 99688.jpg 99689.jpg 99690.jpg
     
  32. Allan Wolff

    Allan Wolff Moderator
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    Re: Dial and Hands for the Pinwheel Skeleton Clock

    The dial is made from a sheet of 1/32” brass. A disk is cut and mounted to the large wood form used to make the pan. The outside is turned to a diameter of 5 inches and the center hole is drilled and bored to .465” as shown in the first photo. Test fit the dial into the trepanned area of dial pan to make sure it is the correct size. Care is required when turning the outside diameter of the thin material as it may flex and grab the lathe tool. A photocopy of the dial shown in the second photo is printed to scale so the outside diameter is 5 inches. The copy is then attached to the brass sheet with adhesive spray, making sure the mounting screw holes are located in areas that are cut away. After the center sections are removed with a jeweler’s saw, the edges are filed smooth and all surfaces are sanded to a 600-grit finish.

    There are a number of ways to put the numbers on the dial including CNC machining, silk screens, hand painting, hand engraving and photo etching to name some of the most popular. A dial may also be purchased and adapted to fit this clock. Each has its own benefits and drawbacks so the builder should chose the method that works best for his skills and equipment. Having neither the artistic talent nor tools necessary for any of these techniques, I send the dial out to an engraving shop to have the numbers photo etched into the dial. Yes, I admit it, another person had a hand in making a part of this clock. However, this was much more economical that acquiring the materials needed to do the work myself. Maybe next time I will try etching the dial myself. 100157.jpg 98543.jpg
     
  33. Allan Wolff

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    Re: Dial and Hands for the Pinwheel Skeleton Clock

    The local engraver I used was able to use a PDF file of the CAD drawing to generate the photoresist mask and acid etch the face. He then painted the face with black paint and sanded it, leaving paint only in the etched numbers and then lacquered the dial to protect it. It looked very good, but in hindsight, several steps should be completed by the clock builder and not the engraver. Most engraving shops make plaques and nameplates, not silvered clock dials, so their finishing techniques may create more work for you if careful instructions are not given. First, the dial should not be lacquered as it will need to be removed to allow graining and silvering. Second, the engraver used 220-grit sandpaper to remove the excess paint. Restoring the 600-grit finish required the removal of enough brass that paint was also removed from several small areas of the numbers. If you use a similar process, request that the engraver paint the dial and let you remove the excess paint with 600-grit sandpaper as part of the graining process.

    Four #50 mounting holes are drilled prior to graining the dial. These holes are drilled near the edge at 4 equally spaced locations as can be seen in the finished dial of the second photo.

    The dial is grained in a circular direction. The center spokes will show on the front and back, so the dial is grained on both sides using 600-grit sandpaper. The dial is placed on the smaller top form used to make the dial pan. A scrap metal rod is placed through the center as shown in the first photo. Another wood block with a hole at one end serves as the sanding block. The sanding block is filed to a slight curve on the working surface to prevent the edges of the paper from snagging on the dial. With a piece of 600-grit sandpaper wrapped around it, the sanding block is rotated around the rod while pushing down on the dial to create the grain. The dial is examined often to make sure the grain is consistent and all other marks are removed. Scratches will become very obvious when the dial is silvered. Remember to grain the back of the spokes and the entire front of the dial.
    You may be tempted to try graining the dial by rotating it in the lathe. I found I had too little control over the process and the graining would not come out evenly.

    The dial is washed with dish soap and water after the graining is complete. Latex or similar gloves should be worn to prevent any oils and fingerprints from getting on the dial that will show up during the silvering process. Inspect the painted numbers carefully after the graining is complete and touch up any areas with a fine brush if any paint has worn through.

    Silvering salts are the traditional method of coloring the dial. A small amount of silvering salt is applied using a soft damp cloth and enough water to form a soupy paste. I wear latex gloves while applying the silvering, mainly to prevent contamination and fingerprints. The cloth is rubbed over the dial using very light pressure in a circular pattern to work the salt over the entire surface. After about 10 minutes the dial will have a uniform dull gray color. The dial is rinsed in cold water and then the finishing powder is applied using a light circular motion. The finishing powder will quickly turn the dull gray into a bright silver finish. The dial is rinsed thoroughly and dried with a soft cloth. The dial is inspected to ensure the silvering is even and then set aside for a day or two and inspected again.

    The silver will become dull if left unprotected, so a coat of clear lacquer is applied to help keep the dial bright. The second photo shows the completed dial after being finished with Mohawk (now Behlen) brand lacquer for brass. This lacquer does an excellent job of protecting metal and is easy to apply. I apply one heavy coat, almost to the point of running, and then lay it flat so the lacquer self-levels to a smooth, glossy finish. Apply the lacquer in cool temperatures, around 70 degrees. This allows the lacquer to dry slower and level out, helping to prevent orange peel. Test other clear lacquers before using them on the dial. I had a terrible experience with a well-known brand that instantly developed an orange peel surface and easily flaked off the dial. The dial had to be re-sanded, grained and silvered. The gloss of the Mohawk lacquer looks nice over the grained dial. If less gloss is desired, 1500-grit sandpaper can be used with the graining setup shown in the first photo to knock down the gloss. Very light pressure should be used to prevent sanding through the lacquer.

    If you look closely at the dial in the second photo, you can see the 4 mounting holes. Also notice that I added my name and the year at the bottom of the dial. A bit of vanity I guess.

    The hands will be made next. 100910.jpg 100912.jpg
     
  34. Allan Wolff

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    Re: Dial and Hands for the Pinwheel Skeleton Clock

    The method I use to make the hands is to make a scale photocopy of the drawing shown in the first photo and use the copy as a pattern. The pattern is glued to a sheet of 1/32” mild steel with spray adhesive. Small pilot holes are drilled and the hand mounting holes are cut out with a fine tooth 2/0 jeweler’s saw before cutting the outside shape. This provides extra material to clamp the stock while drilling and sawing. Attempting to drill the large mounting hole of the hour hand in material this thin will result in the large drill grabbing the thin sheet metal and ruining it. After sawing, the insides of the mounting holes are filed to shape. The hands should be test fitted to the minute and hour pipes during filing to ensure a good fit.

    After the hands have been cut out, the edges are rounded on the top side to give them extra dimension. This is easily accomplished by clamping the hand to a 1/8” rod as shown in the second photo and pulling a strip of course 180-grit sandpaper over the edges. The rod provides support to prevent the hand from being bent. A small machinist’s clamp holds the hand to the rod. Extra care is required when working around the delicate points. The edges can also be filed, but I find the sandpaper provides a more even finish. The faces and edges are smoothed with progressively finer grits of paper. I use water when using 600-grit paper and above to provide a better finish.

    The hands are brought to a mirror finish with a polish such as Simichrome or extremely fine abrasive paper such as Micro Mesh. This paper is available up to 12000 grit, but I found no significant improvement between 8000 and 12000. Absolutely all scratches must be removed or they will become much more visible when the hands are blued. It is also important to clean the hands to remove any oils or contaminates that will show up during the bluing process. I like to use denatured alcohol.

    The hands will be blued next. 102004.jpg 102005.jpg
     
  35. Re: Dial and Hands for the Pinwheel Skeleton Clock

    A good explanation of how you do things, Allan. Interesting to see how others perform these tasks. Thanks.
     
  36. Raynerd

    Raynerd Registered User

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    Re: Dial and Hands for the Pinwheel Skeleton Clock

    Yes, thanks Allan. I`ll be needing to make some hands soon so this is certainly going to be useful.
    Chris
     
  37. Allan Wolff

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    Re: Dial and Hands for the Pinwheel Skeleton Clock

    A traditional method of bluing steel is to heat the part on top of a bed of brass filings. The part is removed when the correct color is reached. That method did not work with these hands with their broad spades and very fine points. About the time the spade reached the correct blue color, the point and arms will have already become too hot and turned gray. An improved method is needed to achieve the desired results.

    A pile of brass filings is placed in the center of a cast iron skillet. The pile should be at least 1/2" deep and large enough to easily hold the hands as shown in the first photo. The filings and heavy cast iron skillet help to provide even heat distribution. The filings are heated to 575 to 590 degrees F. This temperature corresponds to a dark blue color. The temperature is monitored with a suitable thermometer. The probe of the thermometer is inserted into the middle of the pile and a lid is placed on the skillet to help regulate the temperature as shown in the second photo. I used a thermometer with a 10 inch long probe that is made for deep frying. It only goes up to 550 degrees so I am overranging it a bit, but it did not seem to suffer from the abuse. The temperature is maintained for 10-15 minutes to make sure it remains steady. Patience and small adjustments are required since there will be quite a bit of lag due to the mass of the skillet.

    Before beginning the process, make sure a bright light source is available. A halogen desk lamp provides a good white light source needed to accurately see the color changes. A pan of water should be placed nearby to cool the hands when the correct color is reached. A pair of tweezers or pliers is needed to handle the hands. Use care to prevent the hands from being scratched.

    When the temperature of the filings is stable, the lid and thermometer are removed and a hand is placed on the brass filings with the tweezers. The hand is moved in small circles while pushing down on it until the hand is completely buried in the filings except for a small area where the tweezers were located. This provides a window to monitor the color change. The color should change in just a few minutes. When the hand is close to the desired color it is removed with the tweezers and inspected. If it has not reached the correct color, bury it back in the filings for a bit longer. Move it to a different spot in the filings if it looks like one end is progressing faster than the other due to hot spots. The thin areas of the hand should not overheat since the filings are at the correct temperature. When the hands have a uniform dark blue color, cool them in the pan of water. The hands are then dried and coated with car wax to help prevent rust. Clear lacquer is not recommended since it tends to change the color of the bluing.

    I find it very difficult to get a good photo of blued steel since the hands appear differently depending on the lighting conditions. The hands appear black in the third photo. The fourth photo was taken with halogen lighting and shows the blue color on the spade of the hour hand while the arm looks black, yet they are the same color. Also notice the minute hand did not blue very well at the mounting end, probably from insufficient cleaning or a fingerprint. This may be covered by the hand washer. If not, I will need to polish and re-blue the entire hand. 103299.jpg 103300.jpg 103301.jpg 103302.jpg
     
  38. tok-tokkie

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    Re: Dial and Hands for the Pinwheel Skeleton Clock

    I much appreciate that detailed explanation & the pictures. That is a task that lies ahead for me so I have saved the link in my file of useful internet stuff. Using proper white light with 2 pictures to illustrate your point = nice.
     
  39. Allan Wolff

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    Re: Dial and Hands for the Pinwheel Skeleton Clock

    A collet is required to mount the hour hand with a friction fit on the hour pipe. It is machined in the same way as the motion works pipes, so I won't go into any further detail. Slots are cut in the lower section with a jeweler’s saw to allow adjustment of the friction fit. The first photo shows the hour hand collet placed over a scrap rod held in the bench vise to hold it while the slots are cut. The hour hand is a tight friction fit on the upper section of the collet. If the hand is loose, the collet can be expanded slightly with a tapered punch. I prefer Loctite to fasten the hand as it provides better control in positioning the hand and can be easily removed with heat. The completed collet and hour hand are shown in the second photo. I made a design error on the hour hand collet. Notice that the collet is flush with the hour hand. The collet should actually be above the hand by a small amount, say 1/32". This will keep a small distance between the hour and minute hand so they do not hit each other as they rotate. I will either remake the collet or place a thin plastic or Teflon washer between the hands.

    I stole an idea I saw on a pocket watch for the minute hand washer. The washer is equipped with a square arbors on each side. The larger arbor is the same size as the fuse winding arbor and allows the hands to be moved with the key. This provides a means of setting the time without touching the delicate hands or dial. The smaller square engages the minute hand so that it does not slip.

    The washer is turned from 3/8” mild steel rod. I completed as much machining, drilling and finishing as possible before parting off the washer. The smaller center hole is drilled first and then partially drilled through with a larger bit to provide a countersink for the mounting screw. The large arbor is then milled in the same manner as the fusee winding arbor. The small arbor is then milled by cutting through the stock as shown in the third photo. While the stock is still mounted in the lathe chuck, the surface of the washer is finished to a mirror surface by sanding to 1500 grit and then polishing with Tripoli compound and a buff mounted in a Dremel tool. The washer is then parted off, leaving the required amount of the smaller square on the washer. The finished washer is shown in the fourth photo.

    The minute hand, minute pipe and hand washer are test assembled. The height of the squares on the minute pipe and washer are filed down so that both parts protrude half way through the minute hand. The washer and minute hand are fastened in place with an 0-80 machine screw.

    Thats it for the dial and hands. I will start a new thread for the few remaining parts and final assembly. 103972.jpg 103973.jpg 103974.jpg 103975.jpg
     
  40. Allan Wolff

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    Finishing the Pinwheel Skeleton Clock

    The clock itself is now complete and only a few “accessories” remain. Among these are the base plate, feet, key, pendulum lock and case.

    The clock needs to be mounted on a stable platform. A combination of wood and brass are used to provide an attractive display. The clock sits on a base plate made of 1/4” thick brass. The plate is first sawn slightly oversize and the sides are then squared up and brought to their final dimensions on the mill. A decorative edge is then cut around the perimeter with a 3/8” ball end mill as shown in the first photo.

    Dimensions for the mounting screw locations are measured from the assembled plates and transferred to the base plate. The holes in the plate are drilled 5/32” which is slightly larger than necessary to clear the 6-32 screws. This provides additional clearance to allow for slight variations in alignment between the movement and the base plate. Also, the oversize holes will be covered by the feet. The finished base plate is shown in the second photo.

    The feet serve several purposes besides providing a little extra detail. They cover the oversize holes in the base plate and can also be varied slightly in thickness so the clock plates sit firmly on the base plate without rocking. The feet are constructed using the same methods as the plate washers. The center hole for all 4 feet is drilled first. The radius detail is then cut with a profile tool and the entire surface is sanded to 1500-grit and then polished with the Dremel tool. Sanding and polishing will tend to round the top edge. A light pass across the face with the parting tool will restore the sharp edge as shown in the third photo. Also note the profile and parting tools are both mounted on the lathe to help speed up production. The tool is then positioned to part off the foot at the correct height as shown in the fourth photo. Since the parts are polished, I catch them with a piece of wire so they do not get scratched when they drop off. Adjustments to the thickness of the feet will be made during final assembly.

    The key will be made next. 104753.jpg 104754.jpg 104755.jpg 104756.jpg
     
  41. Allan Wolff

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    Re: Finishing the Pinwheel Skeleton Clock

    I have chosen to use W.R. Smith’s signet key design that he described in his book "How to Make a Grasshopper Skeleton Clock". It provides a personal touch and is also comfortable to use.

    The head of the key is made first. The inscribed letter can be easily changed by printing the desired letter and font with a word processor. Some experimentation will be required to fit the letter inside the circle. The design is then fastened to an oversize sheet of 1/8” thick brass with spray adhesive as shown in the first photo. The interior is cut out with a jeweler’s saw. The sheet is then mounted to a wood block in the lathe and centered. A sharp V-shaped lathe tool is used to cut a terminating circle around the letter as shown in the second photo. This helps the letter stand out from the key head. I turned the lathe by hand while feeding the tool into the part until the desired depth is obtained. The outline of the head is cut and filed to shape followed by sanding the entire part to a 600-grit finish.

    The stem is made from brass rod. The small end is machined and drilled. This hole will be squared up later to fit the winding arbor. The part is reversed in the lathe and the larger end is turned to the proper diameter and length. An index plate is then installed to lock the headstock and the milling spindle is used to cross drill the hole for the retaining pin.

    A slitting saw is used to cut the slot in the stem for the head of the key. The third photo shows the 1/8” slot being cut in two passes with a 1/16” slitting saw. The last pass is adjusted by test fitting the head of the key to ensure it fits snugly in the slot. The end of the key stem is then rounded with a profile tool in the same manner as the plate screws. Light cuts should be taken to ensure the tool does not grab on the slot.

    Needle files are used to square the hole in the key stem. The hole is filed and test fitted on the fusee winding arbor until it slips on easily with minimal slop.

    With the key head fully installed and centered in the stem slot, there should be no slop between the small tab of the head and the stem. If the parts are loose at this point, apply a bit of Loctite during final assembly. The retaining pin hole is drilled through the head using the existing hole in the stem as a guide. A 1/2” long retaining pin is made from brass and sized for a tight fit in the hole. The length of the pin is trimmed so it slightly protrudes on each side and then peened with a hammer to rivet it in place. After final finishing, the pin should be nearly invisible. I polished each piece separately, touched up the area around the pin after peening and then lacquered the entire key after it was assembled.

    The finished key is shown on the left of the fourth photo. The key on the right has a steel head and was made several years ago when I built Smith's grasshopper skeleton clock. 105306.jpg 105307.jpg 105308.jpg 105309.jpg
     
  42. Re: Finishing the Pinwheel Skeleton Clock

    Such a beautiful job on the key, Allan. Very classy.
     
  43. Raynerd

    Raynerd Registered User

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    Re: Finishing the Pinwheel Skeleton Clock

    Allan, absolutely amazing work, blows my attempts out of the water. Everything you make seems spot on!
     
  44. Allan Wolff

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    Re: Finishing the Pinwheel Skeleton Clock

    Thanks Dean and Chris for your encouraging words (And Chris, I have to say your work on the gearless clock is first class.) I only have a few parts left to make and then this project will be DONE!!


    When moving a pendulum clock, the pendulum should be removed or secured to prevent damage to the bob or suspension spring. I chose to make a pendulum lock that requires no tools and can be quickly installed to hold the pendulum securely in place when I need to move the clock.

    The lock is basically made to fit and can easily be constructed without dimensioned drawings. It consists of a small block of wood approximately 3/4” long with notches at each end to accept the pendulum and rear plate. A length of music wire is bent in a sigma shape ( ∑ ) to form a retaining clip. The clip is covered with heat shrink tubing to prevent scratching the plate or pendulum. The first photo shows the block and clip and the second photo shows how the pendulum lock installed.

    This is the final piece of the clock. Next time, I will go over some of the methods used to polish and protect the parts. 105694.jpg 105695.jpg
     
  45. Allan Wolff

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    Re: Finishing the Pinwheel Skeleton Clock

    Now that all of the parts are complete, we can move on to applying the final finish. Although a matte finish is sometimes used, I prefer to polish the brass and steel to give it a high degree of reflectivity. Polishing involves a great deal of effort to obtain a satisfactory finish. The process can be tedious and time consuming, so I take advantage of any opportunity available to speed up the process.

    Throughout this project, each part was sanded to a 600-grit finish. It was necessary to re-sand some of them to remove scuff marks that were picked up from handling or test assembly. The parts are then progressively sanded to the highest grit available to reduce the amount of polishing required. I found some 2500-grit sandpaper at a local tool store, but I fear it is being phased out since I have been unable to find it listed in any catalog.

    Parts that can be returned to the lathe are quickly polished by slowly rotating the part in the lathe while buffing the part with tripoli compound and a Dremel tool as shown in the first photo. The lathe chuck used here has soft aluminum jaws to prevent scratching. Other parts that are large enough provide a safe grip may be buffed with tripoli compound and a cloth wheel mounted on the bench grinder. This requires a great deal of caution for a number of reasons. The buffing wheel will tend to grab corners and pull the part from your hands. Corners can quickly become rounded if polished too much, especially on parts made of brass. Also, the parts will become very hot during buffing so leather gloves should be worn.

    I chose to polish the plates by hand due to the number of edges and corners that could be caught by the buffer. The second photo shows how I wrapped sandpaper around a needle file or strip of wood to finish the interior edges of the plates. The plate is shown clamped in the wooden vise of a Workmate bench. After sanding the edges and faces to a 2500-grit finish, Simichrome was used to bring the brass to a mirror finish. the third photo shows my grimy hands with a strip of cloth and Simichrome being used to polish the edges of the plates. It is ironic that the final steps are sometimes the dirtiest.

    A special technique is used to polish the grooves of the fusee. A buffing wheel will quickly round off the edges of the grooves. Instead, the fusee is mounted in the lathe while applying Simichrome polish with the edge of a piece of wood, following the groove across the fusee as it slowly rotates.

    Brass will turn dark if not protected from oxidizing. Clear lacquer is the most common method of sealing brass and it was used on most of the exposed brass parts for this clock. I had significant difficulty applying lacquer to the plates. Spraying from multiple directions to cover all of the edges and corners resulted in areas of overspray. Dipping the plates in thinned lacquer also proved unsatisfactory as the corners tend to hold excess lacquer causing runs and sags. In the end, the rear plate received a somewhat adequate coat of lacquer and the front plate was protected with Renaissance wax. The waxed front plate currently looks more reflective, but time will tell which coating better protects the brass. Steel parts are polished and protected with wax to help prevent rust.

    The fourth photo shows 128 individual parts and approximately 50 small screws that make up the clock (if my count is correct.) The next post will cover final assembly and adjustments. 106338.jpg 106339.jpg 106340.jpg 106341.jpg
     
  46. Allan Wolff

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    With all of the parts polished, it is FINALLY time to assemble the clock! I purchased a dozen pair of inspection gloves to help prevent finger prints during assembly. these worked OK but cotton gloves are a pain when working with some of the smaller parts; perhaps latex would work better.

    All bearing surfaces and holes were cleaned to remove any lacquer and oiled with good quality clock oil. The pallets and crutch pin also require oil. As each piece is added, checks are made to make sure everything aligns properly without any binding. Once the clock is completely assembled, the mainspring is wound 1.5 turns to establish the proper fusee tension as we determined when the fusee was built. For the first run, I wound the fusee only 1/2 turn just in case the clock needs to be disassembled to correct a problem.

    The base of the clock is leveled and the pendulum is set in motion. I then adjusted the crutch until the beat was steady and even. After the clock ran for a few hours without any problems, the fusee was fully wound. During the first full wind, it is important to make sure the fusee stop engages correctly as the cable approaches the end of the fusee (and breathe a sign of relief knowing the mainspring did not explode and destroy the clock).

    I ran the clock for a full week or two before attempting to regulate the clock. This will allows the pallets and arbors to “settle in”. During the first week, the clock lost about 45 seconds each day; not bad considering the pendulum was simply "put together" with no attempt at calibration. After a few adjustments and 3 weeks of run time, it is now losing about 5 seconds per day as I sneak up on the correct setting.

    I am not going to cover how the case was built. Most people will want to have a case that suits their own tastes and quite frankly, a case or dome can be purchased much cheaper than it can be built! My case uses 1/2" square brass rod on the corners with brass strips on the top and bottom to form a cage which holds the beveled glass in place. The front glass is hinged to provide access to the clock for winding.

    All of the wood work for the base and top was done by my uncle, Edward Wolff, who is a master craftsman even if he won't admit it. We had a great time collaborating on the design which uses a combination of walnut and fiddle-back maple. The base has leveling screws built into each corner and a small drawer to hold the key and pendulum lock. 48 high-brightness LEDs are mounted in the recessed area of the top to light up the clock.

    Some closing thoughts.
    What you have read in these posts over several months has taken me 2.5 years to complete; working a few hours here and there and usually a full day on the weekend. Although I did not keep accurate notes, I estimate each plate required 80 hours of work from beginning to end. There is easily 1000 hours of design and construction work involved with the entire project. It is a good thing this is only a hobby and the labor is free.

    Although I do not plan to build another clock like this one, I would change a few things based on what I learned along the way. The escape wheel is heavy and this causes the clock to tick rather loudly. I may building a new escape wheel with lighter materials to see if this helps. More likely, I will experiment with the spring pallet escapement that the original builder used. Whether or not I actually install it remains to be seen.
    I would also change the strategy of saving all of the polishing until the end. This may have saved me from some refinishing to remove scratches from test fitting and other construction activities, but doing nothing but polishing for the last 2 months became very tedious. I actually lost the feeling on a few fingertips for several weeks! On the next project, I will polish the parts in stages along the way and see how that goes.

    I hope you have enjoyed watching this project develop and I have appreciated all of the positive comments and encouragement other members here have provided. Some photos of the finished clock are attached.
    Allan 106519.jpg 106520.jpg 106522.jpg 106523.jpg 106525.jpg
     
  47. Allan, you've done an absolutely beautiful job. It's stunning! Thanks so much for sharing your hard work.

    Dean
     
  48. burt

    burt Registered User
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    Sep 5, 2008
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    Re: Dial and Hands for the Pinwheel Skeleton Clock

    Please allow me to include my comment of most impressive workmanship! Outstanding in every respect.
     
  49. Allan Wolff

    Allan Wolff Moderator
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    Mar 17, 2005
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    Re: Dial and Hands for the Pinwheel Skeleton Clock

    I have created a new thread called "Escapement Angles" and move the related posts to that thread. Please continue the discussion there.
    Allan
     
  50. Allan Wolff

    Allan Wolff Moderator
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    Mar 17, 2005
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    Re: Dial and Hands for the Pinwheel Skeleton Clock

    It has been 6 years since finishing this clock and with the 2017 NAWCC National Convention only 4 hours away in Arlington, I decided to enter it in the Crafts Competition. The judges awarded the clock 2nd place in Class #1 Single Train Movement, Metal category. Considering the exceptional quality of the other entries, I was happy to get second. So, you can imagine my surprise when I arrived the following day to see the People's Choice award sitting next to the pinwheel clock. What an honor! I still cannot believe it.

    The highlight of the convention was getting to talk to the other craftsmen about their projects. I found every single person was passionate about their work and were willing to share their knowledge. If they only lived closer, I would be hanging out at their shops every day learning something new. If you have never attended a National Craft Competition, I highly recommend it. It is worth the trip just to meet the people.
    Allan 309528.jpg
     

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