Building a Strasser Regulator Clock

Discussion in 'Clock Construction' started by Allan Wolff, Jan 28, 2013.

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  1. jhe.1973

    jhe.1973 Registered User
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    #51 jhe.1973, Apr 22, 2013
    Last edited: Apr 22, 2013
    Hi Allan,

    Here in post #26 is the method I use for polishing pinions. I actually built this setup for use in a lathe w/a lever operated crosslide & this is just rigged up with what I had on hand.

    https://mb.nawcc.org/showthread.php?79402-Making-a-new-cut-pinion/page2

    This has the advantage that because the thread on the O.D. of the wood lap rotates the pinion, the polishing retains concentricity of the teeth.

    There are a few tips about constructing this on the above page, but I can go into more detail if you are interested.

    It seems to me that using any kind of abrasive to polish brass wheel teeth would charge the brass surface w/abrasive and the wheel would accelerate pinion wear.
     
  2. tok-tokkie

    tok-tokkie Registered User

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    I realised during the night that my calculation was wrong. It is the torque in the arbors that varies trough the train.
    Torque in escape arbor = 12.7 x 10 / 2 = 63.5 gmm (radius is 12.7/2) (using non SI units, but convenient for this analysis).
    With 2250:1 ratio the torque in Great Wheel arbor = 63.5 x 2250 = 142 875 gmm
    Diameter of cable drum = 21mm. So force in cable = 142 875 / 10.5 = 13 607 g = 13.6 kg.
    On a 2 fall cable system that would be a 27 kg drive weight.

    Your great wheel will turn 20.48 revs in 32 days (60 x 24 x 32 / 2250 = 20.48)
    Each rev of the drum will unwind 65.979 mm so the weight will fall 1351mm in 32 days

    The Sattler Accurata 1958 with Strasser drive uses just 4kg for 30 days. The height of the case is 1.45m so the fall of the weight would be less than 1m. That clock uses ball bearings for the shafts just as you intend. I would expect your clock to run on less weight than theirs because of the increased drop for the weight.

    '------------------
    JHE 1973, many thanks for posting the link to your clock. I recalled that polishing post but had lost track of it.
     
  3. Allan Wolff

    Allan Wolff Moderator
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    Tok,
    Those numbers look correct. 27kg is only 59 pounds! I will definitely need to improve on that or this will turn into an 8 day clock. I am pretty sure the test weight was not accurate and the escapement can run with even less.

    Jim,
    Thanks for the link, that is the polishing system I remember. I may make several smaller wood wheels, one for each grit, and try some of the diamond compound left over from the pallet polishing.
     
  4. jhe.1973

    jhe.1973 Registered User
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    #54 jhe.1973, Apr 23, 2013
    Last edited: Apr 23, 2013
    Hi Everyone,

    You guys are welcome for the link. It was in the repair thread & I was showing the process for a chime clock I have.

    As soon as I can get to it, I think I should start a new thread here in the construction forum with the same info so it will be easier to find for those interested.

    Concerning your concerns about your calculations, I strongly agree with Johnny in his above statement.

    I wouldn't be too concerned with calculations at this stage. They are a great asset no doubt, but to expand on his quote, I feel that each arbor you add brings another flywheel effect into the mix. This stablizes the train by smoothing out the 'shock' of each start & stop of the escapement.

    So, in other words, there is more going on than just force & friction.

    That's my guess & I'm sticking to it.

    :whistle:
     
  5. Allan Wolff

    Allan Wolff Moderator
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    With the weather warming up, yard work has taken up most of my shop time. Fortunately this weekend was cool and rainy so I was able to make some progress on the pinions. Here is my version of Jim's lapping setup.
    DSC_8435.jpg



    I tried to make the lap out of wood but it kept chipping away, so I ended up using a plastic pipe coupling threaded for the 2nd pinion. Thanks to Jim for the tip on using a thread gauge to determine the correct pitch to fit the pinion spacing. The .5 module 2nd pinion used 16 threads per inch and the .4 module 3rd and escape pinions used 20 threads per inch. Here is a closer view of the lapping in progress.
    DSC_8437.jpg




    I used Clover fine valve lapping compound on the first pass. This is a little course but I needed to removed some pretty deep grooves left by the drawing process used to make the pinion wire. The second pass was completed by flipping the pipe coupling over (I threaded both ends) and using 1800 grit diamond lapping compound. This worked pretty well, although I had trouble gripping the plastic coupling with the lathe chuck. Notice that I added a washer on the end of the coupling with a draw rod going through the headstock to help hold it in place. I probably got in a hurry and used too much speed which heated up the plastic coupling enough to soften the threads a bit; it didn't seem to hurt anything, although I used a piece of aluminum to lap the smaller pinions. Here is a view through a jeweler's loop of the pinion after lapping. the lapped section is on the left. I added a red arrow to point to out one of the grooves that needed to be removed.
    DSC_8438.jpg




    Next the pinion was cut to length and drilled to fit over the arbor. It sure was nice that the pinion fit in a collet without requiring a bushing! It seemed like the drill bit wandered slightly on the pilot hole, so I used a small boring bit to bring it back to concentric before reaming the hole to its final dimension of 1/8".
    DSC_8440.jpg


    The pinion is soft and needs to be hardened to improve wear. I used the same method as on the pinwheel clock to harden the pinions. A wire cage is made by wrapping wire around a piece of rod slightly bigger than the pinion and 8 inches of extra wire serves as a handle. A washer is fitted into the bottom of the cage to close it off. The pinion is inserted and another washer is fitted on the top to serve as a lid. The assembly is dipped in a thick mixture of boric acid (roach powder) and denatured alcohol. This mixture keeps scale from building up on the pinion. Here is the assembly being heated. The boric acid mixture makes a nice green flame until the alcohol burns off.
    DSC_8444.jpg


    When the assembly begins to glow red/orange, I start to test it with a magnet. After the pinion and wire are no longer attracted to the magnet, I heat for a few seconds longer and then plunge the assembly into a cup of brine water. I have read that the brine keeps bubbles from forming when the water boils at the surface of the steel, causing the pinion to cool unequally and possibly resulting in uneven hardening or cracks. It seems to work. Here is a shot of the pinion as it came out of the wire cage. There is just a bit of salt-like crust that easily flakes off.
    DSC_8442.jpg




    The pinion then goes into the kitchen oven at 400 degrees F for an hour to temper it. Here are the three pinions fresh out of the oven. The lighting is not very good, but they are a dark straw color.
    DSC_8449.jpg


    All that is left is to polish and attach them to the arbors.
     
  6. Allan Wolff

    Allan Wolff Moderator
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    Spent some time over the last few weeks working on the Center and 3rd wheels. These wheels are each approximately 2.5 inches in diameter with a high tooth count so the clock will run for 30 days. The center wheel has 162 teeth and the 3rd wheel has 160. An alternative would have been to add a 4th wheel. The number of spokes is somewhat arbitrary. I used six to provide good support for the large wheel diameter.
    Wheels.jpg




    For large wheels, I like to mount a wood block on the lathe faceplate and turn the diameter and face so they both run true. A brass disk is cut oversize and fastened to the face of the block with screws. The screws are positioned so the holes will be removed when the wheel is crossed out. This configuration holds the disk securely and provides backup support while the teeth are cut. The brass disk is turned to size and the center hole is drilled and bored to final diameter. Turning the mounting hole and outer diameter at the same time ensures the wheel will run true. The diameter of the disk is colored with layout die or a Sharpie marker so the tooth depth can be set later.


    On previous projects, I cut the teeth on the lathe using an index plate. Since my index plates only go up to 96, I either had to drill a new plate or come up with an alternative way to index. Over the winter, I build a dividing attachment for the Taig headstock using a stepper motor and harmonic drive gear reduction. You can find more information about that project in the tools section HERE.


    The headstock is removed from the lathe and bolted down to the milling machine table using an adapter available from Taig. The bolt holes only line up with the plate mounted front to back on the mill, so the feed direction will be done using the Y-axis. It does not really matter as it is the same number of turns of the handwheel either way. A single-tooth .4 module cutter is mounted in the mill and the table is raised so the cutter is EXACTLY centered on the wheel blank. If it is not centered, the teeth will lean. I run the cutter at 2000 RPM and no oil is used because the brass contains lead. (If I am desperate for material and make a wheel out of 260 brass, cutting oil is needed.) The X-axis is used to adjust the depth of cut. I start out a little shallow and advance the depth of cut a few thousandths, indexing the wheel each time. The depth is correct when just a sliver of layout die is visible on the top of the tooth. This tooth is marked as the starting point. As the wheel is indexed, we need to go all the way around to this spot again to cut the first teeth (where the depth was being adjusted) to the correct depth.
    DSC_8472.jpg DSC_8475.jpg


    After the wheel is cut, the headstock is mounted back on the lathe and a pointed bit is used to mark the position of the six spokes, making sure that none are lined up with the mounting screws. Actually, I could have done this when the blank was turned, but I forgot.
    DSC_8476.jpg
     
  7. tok-tokkie

    tok-tokkie Registered User

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    Lovely high tooth count wheels. Doing that as against using an extra wheel is sure to reduce the required drive weight.
    You say you used a single point cutter yet the picture seems to show a regular multi tooth gear cutter.
    How do you set the tool height to be on the center height of the job?
     
  8. Allan Wolff

    Allan Wolff Moderator
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    I am using a cutter similar to the one in the lower right in this photo of homemade cutters. I purchased a .4 and .5 module wheel cutter in this format. Having read both good and bad, I thought I would give them a try. At 25% the cost of a Thornton, my cheap side took over again. The .4 module works great and makes a nicely shaped tooth. The .5 cutter has some grooves that transfer to the tooth, but I think I can grind or polish these out. Life is too short to work with cheap tools, but I keep doing it :whistle:. The cutters in the photo are all homemade, but these take me a long time to make and the process is rather hit-n-miss with my equipment; interrupted cuts in steel on the little Taig are difficult to do without chatter.
    DSC_1053.jpg


    To center the cutter, I remove the faceplate and install a pointed arbor on the headstock. This is a photo from a couple of years ago showing a multi-tooth cutter being aligned on the lathe.
    Centering Cutter.jpg

    Another way this could be done on the mill (although I have not tried it) would be to align the center of the cutter with the edge of the wheel and then raise the bed half the diameter of the wheel. Should work as long as the Z-axis is accurate.
     
  9. Allan Wolff

    Allan Wolff Moderator
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    Crossing out wheels is a tedious job and I can understand why some people look for ways to use power equipment or event CNC machines to make the wheel spokes. I still use the traditional method of cutting out the spokes with a jeweler's saw and filing to the final shape. I actually like doing it this way and at the same time am always glad when the job is done. I struggled with this process on the first wheels that I crossed out, so I am going to go into detail on the method I use for those that have never done this before, or maybe encountered the same problems.


    I drill and cut out the sections between the spokes in the shop. It is just basic hand sawing that I will not cover here unless requested.


    DSC_8688.jpg


    Each wheel takes several hours to cross out, so I try to get as comfortable as possible. The photo shows the work area, which is the desk in my office. Let's take a tour. Front and center is a 3" cast iron vise that clamps to the desk. Scraps of wood protect the desk from the clamp. Aluminum jaw liners with rubber working surfaces protect the wheel from dents and scratches. (These liners are for a larger vise and I need to cut them off.) A paper towel is placed below the vise on the keyboard drawer to catch the file shavings.
    To the left of the vise are the 5 files I am using on these wheels. From right to left are a #6 crossing needle file, #4 crossing file, #2 crossing file, #2 barrette file, and a triangle needle file. The triangle needle file is from the set shown at the far left; cheap imports that are so soft they will bend. Luckily, they are wearing out and I am going to replace them with real files. The other files are made by Grobet. They are sharp, hard and a pleasure to use. I only use them for brass and they should last a lifetime.
    At the top of the photo is the head of a 50W halogen task light. There are also several bright overhead spot lights to provide good lighting for working under magnification to see the details. Magnification is provided by a pair of 3.0 reading glasses, an Optivisor with a #5 lens and an 8X handheld magnifying glass. I will use these individually or in combination depending on the level of detail I need to see. I prefer to use the handheld magnifier over the flip down magnifier on the Optivisor. I also prefer the reading glasses over the Optivisor, but each has its purpose.
    A 4-inch caliper is shown to the right of the magnifiers. This is typically used to verify that each spoke is the same thickness. Your eye can tell if one spoke is wider or thinner than the others. Important when building skeleton clocks, probably not so much on an enclosed movement. This case will have glass sides and the wheels will be visible, so I want to make it look nice.
    Above the caliper is a Sharpie marker that is used to mark where I started or high spots that need to be filed off.
    A scale drawing is shown on the right of the photo. It is used as a guide to verify the wheel is completely symetrical. Even with the most careful methods of transferring the spoke pattern to the wheel, it is easy to get a spoke skewed slightly; curved surfaces are the worst. It is amazing how well the human eye can detect variations in symetry. I probably transfer the wheel from the vise 100 times or more to compare it to the drawing.
    In the background you can see a computer monitor and keyboard. I may pull up a drawing of the wheel to get impromptu measurements. Mostly I use it to play music from the internet or CDs I have transferred to the hard drive. It makes the time go faster.
    I will go over the steps to cross out the wheels in the next post.
     
  10. Allan Wolff

    Allan Wolff Moderator
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    Crossing out the wheels

    The wheel is first laid on the scale drawing to verify that the lines of the spokes and rim are covered by the wheel. This indicates that the saw work was accurate and we will be able to file the wheel to its final shape. If any lines are showing, see if the wheel can be moved slightly. This is the only opportunity we have to adjust the positioning in order to remove any excess saw cuts. If the wheel cannot be positioned to cover all of the lines, we may just have to live with the over cut.


    A few tips about filing.
    If the files are sharp, brass will be removed rather quickly with the #2 files. Make just a few strokes and then check your progress until you have developed a good feel for how fast the file cuts. Once it is gone, you cannot put it back.
    Keep the file level so the edges of the wheel are crisp and sharp.
    Position the area to be cut close to the vise. This reduces vibration and flexing of the wheel. The top of the vise can also be used as a gauge to verify that the file is perpendicular to the work.
    Hold the file by the handle AND the point, supporting both ends. Rest one of your hands on the vise to steady the file. Take short strokes; .25 to .5 inches. These steps help control the file to keep it straight and make smooth cuts. I find it impossible to keep the file level when taking long strokes. the only time I use long strokes is when there is a lot of material to remove. The final strokes should be short.
    Be aware of what the edge of the file is doing. We do not want to cut an unintended groove in a neighboring perpendicular surface. Some files have smooth edges to prevent this.


    I start filing on the straight part of the spokes near the rim using the #2 barrette file. Mark the first spoke with a Sharpie. Don't worry about getting the corners perfect, we will address that later. Both sides of the spoke are filed, keeping the spoke centered as close as possible to the original layout mark made with the indexing setup. On the first spoke, it is more important to make sure that when the drawing line on both sides of the spoke become visible, the lines on the other spokes are completely covered. This is the only opportunity to adjust the spoke position if needed. When complete, the width of the spoke near the rim is measured with the caliper. All of the remaining spokes should be the same thickness within .001 or so. This is a secondary check rather than relying only on the drawing lines. When filing the remaining spokes, line up the center of the wheel and the first spoke on the drawing. This will determine if material should be removed from one or both sides of the spoke.
    DSC_8720.jpg



    When filing the curved part of the spoke, I begin filing at the center of the wheel with a half-round file until the line begins to show, then use the crossing files to complete the section between the center and straight areas. Use the #2 crossing file to rapidly remove material and switch to the #4 file for the final cuts. The #4 crossing file also works well for draw filing to blend the curved and straight sections.
    DSC_8723.jpg




    Filing the rims requires a different method to hold the wheel since the rim is too thin to provide enough area to clamp it in the vise. Instead, I open up the vise and lay the wheel across the jaw liners. In the photo below, I have one finger resting on the jaw liner for stability while the file is moved up and down with the thumb and index finger. Again, do not worry about getting the corners perfect at this time. The wheel should also be tested on the drawing while filing the rim. It is easy to inadvertently change thickness when moving from one side of a spoke to the other.
    DSC_8728.jpg




    Now let's worry about the corners. I use the small triangle needle file while holding the wheel in my hand. Do not hold the wheel too tightly as it can be bent. Work your way towards the corner from both the spoke and rim until you get a nice sharp corner (as sharp as the file will allow.) It may be helpful to flip the wheel over to view it from the other side to verify the corner looks good from multiple angles. Take your time and be picky. Your eye will be able to tell if one corner is sharp and another is round.
    DSC_8731.jpg




    Now it is time for final clean up. With the wheel mounted as shown in the photo below, I draw file all of the interior edges with the #6 crossing needle file. Draw filing is sliding the file sideways while supporting both end rather than stroking the file from tip to handle. The file can be rolled slightly to get into the corners or prevent the file from digging in as the curve sharpens near the center. I usually move the file back and forth rather quickly with light to moderate pressure. I file the tops of both spokes and half way around the rim on each side, so when the wheel makes half a turn, all surfaces have been draw filed. Draw filing leaves a nice finish and is a good way to smooth out any irregularities. The finish surface can be very smooth as noted by the reflection near the hub. I have never had success draw filing with anything but a Swiss pattern file; other patterns leave grooves in the metal. If your files are not Swiss pattern, you may want to skip the draw filing and finish the wheels with sandpaper.
    DSC_8732.jpg




    I am going to leave the wheels with this finish until final assembly since they will be handled many times during construction. At that time, I will probably sand all surfaces to a 600 grit finish.
     
  11. tok-tokkie

    tok-tokkie Registered User

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    Re: Crossing out the wheels

    Workshop therapy is how I have heard these tasks described.

    I am interested in the 600 grit finish you expect to use. I am nearing the stage where I will have to polish the clock I am building = first I have made. Are you going the polish the framework & wheels to the same grit or have some contrast? You are not going all the way to a high polish or will there then be additional polishing steps? But really what I am interested in is your advice on how shiny (or not so shiny) the clock is going to be and why you prefer it like that.
     
  12. Allan Wolff

    Allan Wolff Moderator
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    Re: Crossing out the wheels

    I have not completely decided on how much will be polished, if any. When I built the Pinwheel clock, I polished everything. It took months (working part-time of course) and it really got tedious. But it is a skeleton clock where every piece is on display, so it needed to be done. The movement on this clock will only be visible from the sides and the main focal point will be the case, dial and pendulum. Still, I want it to look professional. I like your idea of having some contrast. Perhaps I will polish the plates, arbors and a few select parts. Some parts are difficult to polish because of their shape, like wheels, so they will be finished with sand paper. While crossing out the wheels, I experimented with sliding a smooth section of the file over the brass to see how it would burnish. It created a mirror finish in just a few strokes, but had some waviness to it. Perhaps I will burnish the inside edges and sand the outsides to see how the contrast looks. Polished brass looks great, but besides the additional work, it shows every little scratch, imperfection and dust and it needs to be protected in some way (lacquered or preservative wax) or it will tarnish and dull the mirror effect.

    In summary I would say, polish parts meant to be on display and leave parts that only need to be functional with a good satin sanded finish. In the end, it all comes down to your personal preference.
    Allan
     
  13. Allan Wolff

    Allan Wolff Moderator
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    #63 Allan Wolff, Jul 7, 2013
    Last edited: Jul 7, 2013
    Wheel Collets

    Progress has been very slow on the clock for several reasons. Summertime projects continue to consume a lot of time, but the main reason for my lack of progress is that a friend from our local NAWCC chapter has asked me to help him build the same clock. For the past month, we have been working several nights each week on his clock until he catches up. His clock is proceeding much faster since we are building the same parts that I figured out how to build earlier. We have finished the pallets, verge, suspension spring, escape wheel and a few other parts of the escapement. It will likely be another month until we are able to work on the same parts at the same time.
    This should be a good partnership. He is a cabinet maker and is much better equipped for woodworking than me. We will probably build different style cases.




    Meanwhile, I thought I would post some information on the 2nd and 3rd wheel collets. They are identical except the second wheel has a .125" arbor while the 3rd wheel uses .106".
    Collet Drawing.jpg


    As with the escape collet, the part is completely machined without removing it from the lathe chuck. In the following photo, the general outline has been cut out using a parting tool. The face of the collet that mounts against the wheel is being undercut with a curved tool. This removes any radius from the corner and removes a small amount of material from the inner area of the face so that only the outer edge makes contact with the wheel. This keeps the wheel from rocking on the collet. Because of the large contact area, the lathe is turned by hand with light feed pressure to prevent chatter. a few turns is all it takes.
    DSC_9001.jpg


    The center hole is drilled approximately .02" under size and then bored to about .01" undersize. The hole is bored since drill bits tend to wander and this makes sure that the center hole runs true. The boring bar needs to be pretty small as shown in this photo, so only very light cuts can be taken to avoid chatter. The hole is then brought to its final size with a reamer.
    DSC_9008.jpg


    The back side of the collet is rounded with a file and the wheel is attached to the collet with super glue. An index plate and milling spindle are used to drill the 3 mounting holes to the tap size. The wheel is then heated to break the glue bond so the wheel can be removed. A 0-80 tap is then mounted in the milling spindle and the holes are tapped in the collet. The collet is then sanded and parted off and the wheel screw holes are drilled larger to clear the screw.


    This photo shows the completed collets.
    DSC_8998.jpg

    The screws are trimmed to length by screwing them into a scrap piece of steel plate that has been threaded 0-80. The excess is cut off with a Dremel tool. The threads are restored when the screw is backed out of the plate. I am unhappy with the quality of these screws. They are pan head and the screw slot is too shallow, making it difficult to keep the screwdriver seated in the slot. New fillister head screws have been ordered and the screws shown here will be pitched in the trash.
     
  14. tok-tokkie

    tok-tokkie Registered User

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    Re: Wheel Collets

    Two things I learned from this post:
    1. The collet has a recessed flange so only line contact on the outer edge with the wheel.
    2. Glue the wheel to the collet & then drill the screw holes as perfectly registered pairs.
     
  15. Allan Wolff

    Allan Wolff Moderator
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    #65 Allan Wolff, Aug 17, 2013
    Last edited: Aug 17, 2013
    Jewel Settings

    Although we are still catching up on my friends clock, I did find some time to work on the settings for the verge arbor jewel bearings. The jewel bearings I chose were obtained from Swiss Jewel, model R127.0; cost was about $5 each. This is a synthetic ruby ring jewel with straight sides and an olive hole. Outside diameter=.120", hole diameter=.050", thickness=.035". The jewel is too small to mount directly in the plate and some fairly precise machining is required to hold the jewel, so a setting is used. The setting is machined in the lathe and then installed in the plate with a step-drilled hole and small machine screws. Here is a drawing of the jewel setting.
    Jewel Setting.jpg

    A .080 hole is drilled through the setting. The hole is then bored to a diameter of .121" or until the jewel is a nice slip fit into the hole. The jewel is held in place with a bezel. This is basically a flap of thin metal that is folded over the jewel. The bezel is made by plunging a very thin cutter into the edge of the setting to cut a groove about .010" larger that the jewel hole. The cutter is a length of music wire ground to a chisel shape and held in a tool holder with a lathe bit underneath for support. I found that cutting the groove to a depth of .015" works about right.
    DSC_9728.jpg


    The bezel may deflect towards the jewel hole and make it too small for the jewel. If this happens, I put some oil on a piece of smooth rod and burnished the hole until the jewel fits again.
    A step is then cut in the diameter to mount the setting in the plate. The setting is then parted off. Here is a photo (not the best) of the machine work performed on the back of the bezel.
    DSC_9731.jpg


    The setting is now reversed so the front can be machined. Since the jewel is recessed quite a ways from the front of the setting, a taper or cone shape is cut into the front with a counter sink to make oiling easier. This photo shows the setting held in a smaller collet with the countersink held in the tailstock.
    DSC_9729.jpg


    The setting is then cleaned and re-installed in the lathe with the back facing out and the jewel installed. The bezel is now folded over the jewel to hold it in place. To do this, I used a hand-held round graver on a tool rest. With the lathe turning very slowly, the point of the graver is inserted into the groove with the sloped side towards the jewel as shown in the photo below. A small amount of oil on the graver helps to prevent the bezel from tearing.
    DSC_9732.jpg


    When the graver point hits the bottom of the groove, the handle of the graver is pivoted to the right, rolling the bezel over the edge of the jewel. This maneuver takes some practice. I got lucky on the first one and then messed up on the next two attempts. Once I got the hang of it, the results were pretty good. Here are the finished jewel settings. It took me about an hour to make each one, including time to fix mistakes.
    DSC_9736.jpg
     
  16. Allan Wolff

    Allan Wolff Moderator
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    Locating the Arbors

    With the wheels, pinions and plates made, it is time to plant the arbors. I am always a bit tentative about this task because misplacing an arbor by a few thousandth's of an inch will result in poor meshing of the teeth. Mistakes can be fixed, but it is a lot of work and therefore best to get it right the first time.


    The distance between the arbors can be easily calculated but this distance assumes all of the actual component dimensions exactly match the theoretical design. In practice, the teeth may have a slightly different profile depending on how well the cutter was made, the purchased pinion wire could be off-size and so on. Because of these variables, it is best to determine the actual arbor spacing with a depthing tool.


    In clock repair, where the wheels and pinions are already mounted to their arbors, a depthing tool like this is often used. For clock construction where the wheel and pinion are not mounted, the tool shown below works better. Several adapters and spacers are used to obtain a good fit between the wheels and the tool mounts.
    Depthing Tool.jpg DSC_9858.jpg



    The mount for the pinion on the left is tightened securely while the wheel mount is snug but still able to slide on the frame. The screw on the right is used to push the wheel mount towards the pinion in a controlled manner. I suppose a fancier device could also pull the mount back, but this one only pushes. The wheel and pinion are brought together while turning them until they mesh smoothly. Too close and they will bind; too loose and they will run on the tooth tips which requires more power and provides uneven torque to the escape wheel. When the proper distance is found, the points on the bottom of the mounts are used to transfer the dimension to the plates.


    I found that the calculated and measured distances were within about .002"; whether this was luck or skill, I cannot say; but I'll take it. The actual dimensions are used to draw the wheel layout in CAD. The escape arbor is already planted in the centerline of the plates. The only remaining restriction is that I want the winding arbor to also be on the centerline and that there is room for the motion works to be added on the front of the plate. Once the arbors were placed, I let CAD measure the X & Y dimensions between the arbors.
    Wheel Spacing.jpg

    To transfer the arbor location to the plate, one point of the depthing tool is placed in the existing escape arbor hole of the front plate. The other point is used to scribe a small arc in the general location of the third arbor. The location of the escape arbor is carefully measured from the top and left edge of the plate with a dial caliper. The location of the third arbor is then calculated from these edges using the X & Y dimensions from the CAD drawing and their intersection with the arc scribed with the depthing tool. The same process is used from the third to the second abor and from the second to winding arbor. If all went well, the winding arbor will be on the centerline of the plate. As a second check, the measured distance from the escape arbor to the winding arbor should match the sum of the Y dimensions (.756 + 1.367 + 1.220)
    I will explain how the plates are drilled in the next post.
     
  17. Allan Wolff

    Allan Wolff Moderator
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    Bearing Installation

    Now that the arbor locations have been marked on the front plate, the plates are fastened together with alignment bushings and clamped in the mill. The plates are squared with the table and sit on 1-2-3 blocks so I can drill through both plates without hitting the milling table. In the photo below, the pointed end of an edge finder is used to locate the hole for the escape arbor. The mill handwheels are then turned in the X & Y directions by the amounts indicated in the dimensioned drawing in the previous post. If everything worked out correctly, the pointer will be directly over the mark for the third arbor. This is my way of double checking the layout before drilling the holes.
    DSC_9746.jpg



    The 2nd, 3rd and escape arbors will run in 5 X 2 X 2.3mm ball bearings. The bearings are slightly thinner, (.09") than the .125" plates. I will drill a recess part way through so the bearings are flush on the inside of the plate and held in place with a lip on the outside of the plate and the shoulder of the arbor on the inside.
    I have had problems in the past with drill bits wandering, so I decided to drill the initial holes with a 1/8" center-cut end mill. This may upset some people, but the end mill cuts the brass so easily that no vibration or chip loading occurs. The end mill is short and rigid and will drill a nice straight hole. After this hole is drilled through both plates, I remove the end mill holder and install a drill check and enlarge the hole with a 9/64" drill bit. This size was chosen so the lip will not hit the bearing shield or inner race.


    This method of locating and drilling the holes is repeated for the 2nd and great wheel arbors. The great wheel arbor is drilled with a 3/8" end mill to fit the larger bearings. I then went back and drilled out the escape arbor hole for 5X2 bearings. This required several tooling changes for each hole, but I felt it was better to drill all the holes at one setting rather than try to relocate them each time.
    The plates are now separated because the bearing recesses are machined on the inside of the plates. A 5mm end mill would probably have worked great to mill the recess for the 5mm bearing, but I did not have one. Instead, I made a cutter from 1/4" drill rod. The outside was turned to 5 mm and the end was then split with a jeweler's saw and each tooth was ground back for clearance. This cutter is held in the mill in a collet. The brass ring was installed just to make sure the cutter did not slide up into the collet and throw off the measurements. I drilled a test hole in a piece of scrap brass just to make sure the bearing would fit easily with no slop into the recess.
    DSC_9748.JPG DSC_9749.jpg




    Each plate was clamped to the mill table and the cutter was carefully centered over each hole. I originally used the pointed end of the edge finder, but the later holes were just centered by eye. The table was then raised until the recess was .09" deep. Here is a bearing fitted in the recess.
    DSC_9753.jpg


    The bearings for the great wheel are a different configuration. The bearings are 1/8" thick, so there is no room to leave a lip on the outside of the plate to hold the bearing. Instead, flanged bearings were used. These bearings require an shallow 7/16" recess for the flange. Here the recess is being cut with an end mill.
    DSC_9786.jpg



    A front view with the bearings and arbors installed. I will show the arbors being made next.
    DSC_9851.jpg
     
  18. Allan Wolff

    Allan Wolff Moderator
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    Re: Arbors

    #36 (.106") music wire is used for all of the arbors except the winding arbor. #36 is a rather odd size, so why use it? A larger size, say 1/8" would be less likely to flex and is easier to find. However, the pinions that mount on the arbors are rather small and drilling a 1/8" hole through the center would leave the wall thickness extremely thin and suseptible to cracking. Besides, I had plenty of #36 music wire on hand from a previous project. Music wire is used because it is hard and does not bend easily and pivots made from it wear better. Wear is not an issue when using ball bearings and drill rod would probably serve just as well.


    I previously machined the pivots by supporting the music wire in a steady rest to ensure the pivot was concentric with the diameter of the arbor. I got tired of fiddling with the steady rest and decided to make a collet to fit the #36 music wire. I drilled a blank Taig collet to about 10 thousandths under size and then bored it to ensure concentricity before reamed it to its final size. The last step in preparing the collet was to slit the sides with a jewelers saw so it would squeeze around the wire when tightened. This made the machining operations so much quicker and easier.


    Another advantage of using ball bearings is the pivots do not need to be polished or burnished. They are simply machined until a nice slip fit is obtained. I like to machine the pivot so the bearing does not quite slip on, and then sand the pivot to size with 600 grit paper wrapped around a piece of wood. The wood helps keep the pivot surface flat. I then clean up the inside corner with a graver so the bearing will slide up close to the shoulder. A little corner is actually OK since it will keep the arbor from contacting the shield or outer bearing race.


    A few special practices are needed When turning small diameter material. The cutter needs to be exactly on center. If it is too high it will not cut at all and if it is too low the material will want to climb over the cutter, bending or breaking the work. Light cuts and a sharp cutter will also help previent this. Machining should be done as close to the collet as possible. If too much material is sticking out, it will deflect away from the cutter. The deflection will be more pronounced at the end farthest from the collet. The photo below shows this problem. The top arbor is for the escape wheel and will extend through the front plate about 7/16" to mount a second hand. I cut the entire 7/16" length at one time, taking multiple light passes. As the arbor became thinner, it began to deflect more with each pass. The diameter at the end of the pivot is .008" larger than the diameter next to the bearing. I will grind this taper out later, actualy tapering it the other way so the second hand can be pressed on. The bottom arbor is for the second wheel and will protrude through the front plate 3/8" and drive the motion works. It extended 3/16" from the collet with a 1/8" length of cut taken as shown in the second photo. When it was the correct diameter, the material was extended another 1/8" and turned to size. This was repeated until the 3/8" length was machined. The entire pivot was then finished with 600 grit sand paper. It has no taper.
    DSC_2012.jpg DSC_2000.jpg
     
  19. Allan Wolff

    Allan Wolff Moderator
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    Winding Arbor, Drum and Ratchet

    The winding arbor is made from 5/16" mild steel rod in a similar way as the other arbors. Each end is reduced to 1/4" for a nice slip fit into the bearings. A groove is cut with a parting tool that will catch a slip washer used to hold the great wheel assembly in place. The end is cut square in the mill using an index plate as shown in the second photo. I have found this much quicker and more accurate than attempting to file the square end in the lathe with a file rest. This drawing shows the winding arbor along with the great and maintaining wheels which will be made in the next post.
    Great Wheel Drawing.jpg DSC_0960.jpg DSC_2383.jpg


    The winding drum and ratchet was designed to be cut from a single piece of 1.25" brass rod. I did not have any material in this diameter so a disc was cut from 1/8" brass and fastened to the end of a 1" rod with three countersunk screws. This worked out OK but buying the larger diameter material would have saved an hour or so of fiddling with making and fastening the disk. The entire winding drum and ratchet were cut and the hole drilled and bored as one unit so everything will run true. Leaving the drum as one solid piece adds a little weight, but that will not affect the performance of the clock since this assembly makes less than 1 revolution each day.
    Cutting the ratchet teeth used the same techniques as cutting the escape wheel so I will not go over those details again.
    The rounded edge of the drum is shaped with a file. A groove is made with a a parting tool as if the drum is being cut off. This groove provides enough space to round the outside edge with a file. After the drum is sanded to a 600 grit finish, the parting tool is inserted back into the groove to finish the cut separating the drum from the stock.
    DSC_2382.jpg DSC_2387.jpg
     
  20. Allan Wolff

    Allan Wolff Moderator
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    Great Wheel and Maintaining Wheel

    This clock will use the same configuration for maintaining power as my pinwheel clock with a few modifications. Construction details can be found HERE so I will point out some of the differences in this post.


    The great wheel is almost the same diameter as the pinwheel but this one has 150 .5 module teeth instead of the pinwheel's 96 .8 module teeth. We need more teeth to get a 30-day run. See the previous post for dimensions. I have to say that the .5 module single-tooth cutter I purchased has been a disappointment. While the .4 module cutter of the same design cuts beautiful teeth, this one has some problems. The addendum radius (curved part of the tooth) is not symetrical. One side is more flat than the other. As long as the side contacting the pinion has the correct radius, I should be OK since the other side is just for clearance. If it is the other way around, this could cause some power loss. Another problem with this cutter is it somehow makes the teeth lean or slant to one side. Leaning teeth is typically a sign the cutter is not on center with the wheel. However, I have cut several wheels and verified that the cutter was on center. In fact, when we cut a second great wheel for my friend's clock, the teeth leaned even more. I was able to borrow a Thornton cutter from another member of our local NAWCC chapter and after seeing the perfect teeth it cut, we threw away his wheel and made a new one. The old single-tooth cutter also went in the trash! (Didn't I say something earlier about buying cheap tools! Somebody kick me.) Since my great wheel is done, I am going to use it and see how it performs. If my friend's clock takes less power to run than mine, the great wheel will be the first thing I replace.
    DSC_2388.jpg


    The maintaining wheel has a few more modifications from the pinwheel design. This is primarily because this clock is weight driven and has no fusee. A larger click can be used since it does not need to fit inside a fusee and the click spring will be moved to the rim of the wheel which seems to be a more traditional design. Here is the finished maintaining wheel.
    DSC_2393.jpg


    You can see part of the click spring peeking out from the bottom side and the threaded hole is where the click will mount. I will cover the click, spring and slip washer in the next post.
     
  21. Allan Wolff

    Allan Wolff Moderator
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    Re: Great Wheel and Maintaining Wheel

    Here is a drawing of the click, click spring and shoulder screw.
    Click-Spring Drawing.jpg


    The click is made from 1/8" thick steel. The only dimension of concern is the distance from the center of the mounting hole to the tip where it contacts the ratchet. This distance is needed to determine the correct mounting position of the click. The second drawing shows the click and ratchet. A red line is drawn from the center of the mounting hole to the tip. A second line is drawn perpendicular from the tip towards the center of the ratchet wheel. If the perpendicular line falls between the click and the center of the ratchet wheel as shown, the counterclockwise rotational force from the ratchet will tend to pull the click down into the ratchet, keeping it seated. If the click were mounted closer to the center of the wheel, the perpendicular line would fall on the other side of the ratchet wheel center and the rotational force of the ratchet would tend to push the click up away from the rachet causing it to release.
    Barrel Click Geometry.jpg


    The shoulder screw is made so that the click will rotate smoothly on the shoulder without any unnecessary slop. The shoulder is a little taller that the thickness of the click so the screw can be tightened down without clamping the click. I like to cut the threaded end of the screw first and then finish the head by screwing it into a scrap rod with matching threads. This photo shows the screw after the head just before the slot is cut with a slitting saw. I cut the slot last so the head can be polished without rounding the edges of the slot. The next photo shows the finished click and shoulder screw.
    Screws Polishing.jpg Barrel Click&Screw.jpg


    The click spring is made from 1/16" thick tool steel. Tool steel is more springy that mild steel. The spring is cut straight as shown in this photo and then bent by hand around a bar to get the desired shape. The spring is fastened to the maintaining wheel with a single screw. A pin made from music wire is added to the tail of the spring to keep it from rotating. Note in the final photo that the spring rides on the click near the mounting screw. This reduces the amount of flexing the spring goes through, thus reducing stress so it will retain its shape better.
    DSC_2366.jpg DSC_2396.jpg

    The slip washer is made from brass rod. A center hole is drilled to 1/4" diameter and the edge is beveled before the washer is parted off. The washer is then mounted in the mill and centered. The holes for the mounting screw and large offset opening are measured from the center and drilled with center cutting end mills. The washer is then re-centered and the slot is cut with a 1/4" end mill.
    DSC_2398.jpg DSC_2400.jpg
     
  22. Allan Wolff

    Allan Wolff Moderator
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    A Heavy Decision

    Enough of the components of the time train are complete so the clock can be run to determine the amount of weight required. I cleaned up the pinions, collets and arbors and assembled them with Loctite 609. I like to use Loctite as it is easier to locate the parts and less stressful on small clock parts than a press fit. Loctite 609 is a retaining compound with a minimum shear strength of 2300 psi. The bond is pretty much permanent unless the parts are heated above 150 C which is convenient if disassembly is required, but not hot enough to pull the temper from the metal.


    I suspended a basket from the winding drum with 85 lb. fishing line and rigged up a temporary pendulum. Weight was added until the escape wheel was able to just drive the impulse pallets until the escape wheel tooth hit the lock pallet. Occassionally a tooth could not reach full lock, but the movement ran for 5 minutes without loss of pendulum amplitude. This gives me confidence that the minimum drive weight had been found at 8 lb. 15 oz. Call it 9 lbs. This weight will need to be doubled when a pulley is added. Since the escape wheel was barely driving the impulse pallet, 10% will be added to ensure reliable operation. This gives a grand total of 19.8 pounds for the drive weight. That is a lot less than the 59 lbs. calculated in post #53, but still a seriously heavy weight. I hope that less weight will be required as the movement "runs in". If I applied tok-tokkie's equation correctly, the power required to drive the clock is 21.5 uW. That seems reasonable and an equivalent weight for an 8 day runner would be 5 lbs.


    So now a decision is required and I would really like to hear what others have to say regarding the drive weight.
    The current drum diameter is .827" which gives a drop of 26.6 inches in 32 days with a drive weight of almost 20 lbs. Increasing the drum diameter lowers the weight required but also increases the drop. The increased drop can be accommodated by using a shorter, fatter weight, making the case longer or a combination of both. Here are some samples from my spreadsheet.

    Drum Diameter (in.)Drop (in.)Weight (lbs.)
    .83 (current)26.6019.80
    .8527.3419.26
    .9028.9518.19
    .9530.5617.24
    1.0032.1716.37
    1.0533.7815.59
    1.1035.3914.89
    1.1537.0014.24



















    With about 2" clearance below the pendulum rating nut and allowing 9" for the length of the weight and pulley, I have about 31" of drop available. Extending the case is possible but it will have a less traditional look that other Laterndluhr cases. This case also has a narrow waste so there is not enough room to move the weight to the side and raise it above the movement. Also, with this much weight, I better keep it in the center of the clock.
    Right now, I am leaning towards increasing the drum to 1" and shortening the weight about 1" to reduce the weight to 16.37 lbs. The weight would be 2.75" diameter and a little over 7" long using a lead filled brass tube to maximize density.
    What would you do?
    Allan
     
  23. John MacArthur

    John MacArthur Registered User
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    Re: A Heavy Decision

    Allan -- It's looking really good to this point. I'd say your weight decisions are mostly aesthetic, as you have the minimum drive requirements to adhere to. A few year ago, in a regulator with similar dimension constraints, I tried to find enough tungsten carbide from ruined tools to fill a smaller weight tube. Tungsten carbide is denser than lead, but not as dense as pure tungsten, and I couldn't pack enough pieces in to make a smaller weight than one of cast lead. A cylinder of pure tungsten would make for a mighty small weight. Most top regulators try to keep the weight as far as possible from the pendulum bob, to avoid interference, and this usually means running the line over a pulley at the top of the case, and hanging the weight off to the side. If your case design doesn't allow this, then your choices are more limited.

    I'll be great to see how it runs.

    John MacArthur
     
  24. tok-tokkie

    tok-tokkie Registered User

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    Re: A Heavy Decision

    I was unable to post yesterday because the thread was locked so I sent a PM to Allan. He asked me to post it here. This is it slightly edited.
    ‘------------------
    Density of tungsten is 19 compared to 11 for lead. I don't know about where to get a slab of tungsten though I do know David Walter used it for the weight on his (D)W5 version of Woodward's clock. His is a 30 day clock. Over the years I have always collected all the used tungsten carbide tips from my cnc tools. I would pack the weight with those tips, warm them up then fill the void with molten lead. You will end up with a density much better than lead. Without the lead the air gaps between the bits of TC would drop the density way down.

    Another tip. I have cast lead for the bob & drive weights. You get a lot of dross floating on the lead which spoils the casting. I made a pot with 10mm hole in the bottom which I countersunk from the inside. I turned a 45°point on a 12mm piece of steel rod about 300mm long. Welded a tab to the top of the pot with a 13mm hole above the drain hole at the bottom so the rod was held in alignment with the hole. The rod acts as a valve & seals the hole while the lead is melted. I cross drilled the rod slightly above the guide tab & fitted a small bolt. I was then able to raise the rod with a long screwdriver to open the valve to let the molten lead drain out. I had a little bit of stainless steel instrument tubing jammed into the bottom of the 10mm hole with a 45° bend as a spout. The advantage is you drain the clean pure lead and leave the troublesome dross floating on the top. I can send you some pictures if this description is not clear.

    Picture added. The bob is held on 4 legs so it is stable & I can pre-heat the bottom. Solder in background was used as a Temple Stick to check the temp of the bob.


    Lead Melting Pot_1.JPG
     
  25. Jeff Salmon

    Jeff Salmon Registered User
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    Re: A Heavy Decision

    I have a Keinninger regulator, recent, obviously, but it has a double weight for the time, and springs for the chime and strike. The clock is a large Lanterndulhr style clock and the double weight obscures the beautiful regulator style pendulum. I looked into converting the double weight into a carbide weight. For my project, it was way too expensive. For your project, may be not. There are several companies that can supply the carbide in almost any shape desired. The companies can probably make up a cylinder to your specs, with a hole through the center to allow for a rod to connect the top and bottom caps. There is also a lot on E-bay, but it can be hard to find a ready made piece that is precisely what you want. It seems to be sold by the pound, and the price seems pretty consistent as it is a commodity and traded as such. The beauty of carbide would be your weight would look elegantly small. I also had a project that was a really badly worked on 3 weight marriage clock and case. The three weights had been lightened with something to dig out the lead. I bought some carbide powder and mixed it with glue to add some to the weight. Lead buckshot was not enough as I could not pack it densely enough.
     
  26. Allan Wolff

    Allan Wolff Moderator
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    Re: A Heavy Decision

    I want to thank everyone for their suggestions on the clock weight. I have decided to increase the size of the winding drum to 1 inch and use a lead-filled brass tube for the weight. Since this will increase the weight drop by almost 8 inches, I will need to make up that distance by a combination of extending the case, shortening the weight and raising the fully wound position where ever possible. One place I can make up an inch or so is in the pulley. I had planned to make a decorative pulley with a fancy scroll-cut frame, but instead I plan to mount the pulley to the weight with a bracket, something like this.
    Weight.jpg


    The bracket shown in gray on the left weight may be fretted out to make it look less clunky. Another option shown on the right would be to recess the wheel part way into the weight itself so only half of the pulley is visible. I will have to give that some more thought and am interested in you comments on how this might be done and still make the weight removable.


    Now I know how much weight it takes to run the clock, but I still need to determine how much weight to put in the pendulum bob. On most clocks, the power available to impulse the pendulum is heavily influenced by the drive power. More power gives a harder impulse and thus should drive a heavier pendulum. The additional power also creates more drag needed to unlock the escapement, so lots of factors are at work. The Strasser escapement is different. The power available to impulse the pendulum is almost entirely determined by the outer suspension spring. See post #1. Another test is needed to determine how much weight the clock can drive. I would like to use enough weight to obtain a high Q but don't want to place too much stress on the suspension spring by supporting too much weight. The bob I have in mind will hold about 7 pounds of lead if filled completely full, but I am going to use 4-5 pounds as a starting point.


    I will get to the bob test soon, but this brings up a point that has been nagging me since I built the suspension spring back in post #30. The springs are very thin around the screw holes and I fear that they will break easily. I made a new inner spring to correct this. The old springs are shown on the left and the new one is on the right. (I have cleaned up the rough edges since this photo was taken.)
    Suspension Spring Revised.jpg


    The new spring provides additional material around the screw holes and also wraps around the holes for the bracket and pendulum supports. This should be much stronger while maintaining the same amount of area at the point of inflection.
     
  27. Allan Wolff

    Allan Wolff Moderator
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    Bob Weight Test

    I want to know if the clock can drive a pendulum with a bob weighing 4-5 pounds before the bob is actually built. To make that determination, I performed the "Dr. Pepper Test". The Pepsi challenge would have been a better name and provided the same result, but I did not have the proper supplies on hand. Here is the setup for the test. The movement is bolted to the leg of a metal shelf.
    DSC_3528.jpg


    Now you understand where the name comes from. The large white soda can is the drive weight and holds just under 8 pounds of lead. An eye loop bolt was placed in the molten lead to serve as a hook. This proved trickier than it sounds since the steel bolt FLOATS in lead and it kept wanting to raise up out of the lead. I had to hold it in place with pliers until the lead solidified. The small red can holds 5 pounds of lead and serves as a temporary bob. I drilled a hole through the lead for the pendulum rod which was threaded at the end for a nut.


    The movement ran for 3 days without stopping so the Dr. Pepper Test was a success. This gives me confidence to proceed with making the final bob.


    A few additional notes regarding lead.
    Drilling lead can be tricky. I drilled the small can of lead in the Atlas 10-inch lathe and it went very well until about halfway through when the drill bit generated enough heat to make the lead sticky. It then became necessary to back out the bit often because the chips would get gummed up in the hole.


    The large can is just the right size for a mold of the final weight. I should be able cut off the aluminum can to take a skim cut across the lead to have it slide inside the brass tube. Smaller cans with the same diameter will be used to make smaller weights so the final weight can be adjusted as necessary.


    I had about 20 pounds of wheel weights that I melted to make these weights. A stainless steel can and propane torch were used since that is all I had. A setup like tok-tokkie used would be much better. Although melting the weights was not difficult, wheel weights are dirty and the fumes were terrible. The clips and other dross needed to be separated and it was not an enjoyable task. Since we needed more lead for my friend's clock, we decided to buy lead ingots rather than melt more wheel weights. These are easy to find on Ebay for $1 to $2 per pound delivered. It is worth every penny to work with clean lead and avoid the mess and fumes.
     
  28. GregS

    GregS Registered User

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    Re: Bob Weight Test

    Hey Allen,
    Make those weights from your favorite beer and you'll have yourself a new market!
    Love this thread!
    Thanks for sharing!
    Greg
     
  29. Jim DuBois

    Jim DuBois Registered User
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    Re: A Heavy Decision

    Allan, how thick is the material you are using to make the suspension spring?
     
  30. Allan Wolff

    Allan Wolff Moderator
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    Re: A Heavy Decision

    The suspension spring is made from .005 inch thick blue spring steel.
     
  31. Jim DuBois

    Jim DuBois Registered User
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    Re: A Heavy Decision

    Thanks Allan. Greatly appreciated.
     
  32. Allan Wolff

    Allan Wolff Moderator
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    Making the Bob

    The bob will be made by spinning two shells from brass sheet and soldering them together. I had tried spinning metal several years ago with limited success. The Taig lathe is just too small to handle the forces involved. Now that I have a 10-inch Atlas lathe, I am eager to try metal spinning again.


    A form is made from scrap pieces of oak flooring mounted to a faceplate. The form is 6 inches in diameter with a radius of curvature of 7.4 inches. This gives a bob that is about 1.26 inches thick. Two disks of .020" thick brass sheet are cut to a diameter of 6.25 inches. We used .025" thick brass for my friend's bob and it worked just fine. The 6.25" diameter gives enough material to cover the curve with a little left over to be trimmed later. Each disk is annealed by heating to a dull red color. When annealing brass, it can be allowed to air cool or quenched in water. This is unlike steel which gets harder when quenched. We tried spinning one disk without annealing it, but the brass was too springy and did not want to take the shape of the form. The disk is held against the form with a live center mounted in the tailstock. A section of brass rod was drilled to cover the point of the live center and act as a pad against the disk. Friction is all that holds the disk in place so I always stand to the side when the lathe is first turned on. Haven't had one fly out yet, but it sure looks like it could. An old Armstrong tool holder is used for the tool rest.
    DSC_3118.jpg


    A forming tool is placed at the corner of the tool post and tool rest. The forming tool is a 12" long piece of .5" diameter drill rod with the end shaped like a bullet. It has been hardened and polished to prevent snagging or scratching the brass. The tool is shown below along with the secret spinning lube. On my previous spinning experience I followed a clockmakers advice and used oil and Ivory soap shavings. It worked but also made a huge mess as the mixture was flung off of the disk as it spun. This time I used a mixture of 50% wax from a (new) toilet gasket and 50% way oil. The mixture is heated and stirred until it is thoroughly blended. It is the consistency of grease when cool. The lube was applied with a rag, did not fly off during spinning, and worked great. Here is a shot of the spinning in progress taken with a cellphone camera so lighting is not the best. You can see the disk is about half formed.
    DSC_3131.jpg Spinning Bob.jpg


    We were able to spin the entire disk without needing to re-anneal. Here is the finished shell still on the form. The tool left grooves in the shell but they are shallow and will be sanded out later. Going over the shell with a broad-tipped tool probably would have helped to smooth out some of the grooves. The lip is turned off in the lathe to a diameter of 6 inches. Light cuts must be taken since the shell is only held in place by friction and can easily slip. The shell is then rubbed on a piece of sand paper to clean up the edge and make sure it is flat. The edge needs to be flat so the shells contact each other around the entire edge for soldering.
    DSC_3120.jpg DSC_3125.jpg
     
  33. Allan Wolff

    Allan Wolff Moderator
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    Re: Making the Bob

    After the edges of the shells are flat, holes are filed so the penulum rod will pass through the bob. The rod is .313" at the top and .164" at the bottom for a #8 thread.


    We know that the clock has enough energy to keep a 5 pound bob swinging, so this much weight can safely be added to the shells. The trick is getting the lead into the shells. Soldering the shells together and then filling with lead presents several problems. Getting the molten lead through the small hole for the pendulum rod fast enough before it starts to harden will be difficult. Drilling a long hole through the hardened lead for the rod will not be easy either. I would also need to use high temperature solder to join the shells to prevent the hot lead from melting it and allowing the shells to come apart.


    Instead, each shell will be filled with lead and then soldered together. The inside of the shell was first fluxed and tinned with silver solder. The solder melts at 430 F, so it will be remelted by the molten lead which will be over 622 F. I was not sure how well the lead would adhere to the shells, but a lot of banging around during the remaining bob work confirmed that the bond was very solid. 2 pounds of lead was added to each shell for a total bob weight of 4 pounds, plus a little bit for the brass shells. This did not completely fill the shells, but that is OK since the mass is still centered at the center of the bob.
    DSC_3521.jpg


    A groove was then scraped/cut down the center for clearance of the pendulum rod. In hindsight, this step could have been saved if a rod had been placed in position while the lead was still molten.
    The photo above also shows that the edges have been fluxed and tinned with solder. The shells are now aligned and the edge heated with a propane torch to melt the solder and bond the shells together. The weight of the upper shell was sufficient to hold the two halves together, but there were a few places where a gap appeared. These were closed by heating the area with a smaller butane torch and then squeezing the edges together with a pliers. Here is the assembled bob.
    DSC_3525.jpg


    The excess solder is removed with a file and the grooves are smoothed out by sanding. The grooves proved to be deeper than I anticipated and quite a bit of sanding was needed. To speed up this operation, I removed the platen from the 1" belt sander so the belt could deflect and conform to the shape of the bob. This worked out pretty well although I did have one side with a few blemishes that were too deep to remove. This will obviously be the back side.
    DSC_3640.jpg


    The bob was sanded down to a 320 grit finish. the photo above is staged to show the technique. I wore gloves while sanding since the edge became very sharp and the sanding created a lot of heat. Final wet sanding will be done by hand prior to buffing during final assembly.


    I discovered that there appears to be different materials used in the sanding belts. Sanding with the course 80-grit belt was pretty uneventful. However, the 150 and 320 grit belts created a static charge on me and the bob that was powerful enough to jump a 1/4" gap. After a few powerful jolts I learned to hold the bob close to the sander table so the static would discharge through it instead of me!
     
  34. Tinker Dwight

    Tinker Dwight Registered User

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    Re: Making the Bob

    An alternate way to deal with static is to discharge it
    while it is forming, instead of wait for it to build up.
    A wire from you to the case of the sander would keep it
    from building up and making you flinch.
    Tinker Dwight
     
  35. Allan Wolff

    Allan Wolff Moderator
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    Re: Pendulum Rod

    The bob is complete except for final sanding and polishing, so I can use it to determine the final length of the rod. The rod was intentionally left long for the test run because I did not want to take the chance of cutting it too short. Invar is expensive! I made the top end of the rod when I did the Dr. Pepper test run, but did not show it then. It is a simple slot that is a tight slip fit over the suspension spring. It needs to fit without any slop or impulse power will be lost at the joint. The top of the slot is rounded with a file and drilled through for a #2-56 screw. The screw was made from a steel rod and a knurled head was attached with Loctite.
    DSC_3939.jpg




    I want the rod to be about an inch longer than necessary to allow for adjustment. To determine the length, the bob was attached to the rod with a spacer made from tubing. The spacer raised the bob up to its approximate position. Normally I would run the clock over several hours to determine the beat rate. Fortunately, my friend had a Microset timer which made it very easy to adjust the bob to 3600 beats per hour. Once this position was determined, I added a half inch for the rating nut and one inch for adjustment and cut the rod to its final length of 44 inches. Now I need to machine the end of the rod down to .164" for a #8 thread. Turning a 44" rod in a lathe made for 12" of travel requires a bit of ingenuity to support the free end of the rod. Last year, I purchased a new bed and cross slide for the Taig lathe. Luckily I still had the old one and attached the steady rest to it. This did a great job of holding the free end of the rod while the other end was machined. In this photo, the free end is on the left.
    DSC_3515.jpg


    Standard thread pitch for a #8 screw is typically 32 or 36 threads per inch. I wanted something that would give a finer adjustment. After some searching, I found the local Wholesale Tool stocked a #8-56 die, but no matching tap. I finally found the tap on eBay for $12. I thought that was a bit high, but it was a quality brand name. I was pleasantly surprised to receive an entire box of 12 taps. Apparently I mis-read the ad and I now have a lifetime supply of 8-56 taps at the bargan price of $1 each! Playing around with a calculator showed that 56 threads per inch equates to about 1 second per hour for one turn of the rating nut.
     
  36. John MacArthur

    John MacArthur Registered User
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    Re: Pendulum Rod

    Looks good Alan. If memory serves me right, (now that it's too late!) 40 TPI gives you a pitch that, if you make a nut with 30 divisions around it, will give pretty close to 1 sec of rate change/day/division .

    You've inspired me to start another regulator, but I'm still cutting pinions and gears.

    John MacArthur
     
  37. Allan Wolff

    Allan Wolff Moderator
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    Re: Pendulum Rod

    I had not thought of putting any marks on the rating nut for calibration, but you have piqued my interest. It appears that I can use 24 divisions to get the same 1 second/day/division.
    Thank you for that idea John!
     
  38. Allan Wolff

    Allan Wolff Moderator
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    #88 Allan Wolff, Jun 14, 2014
    Last edited: Jun 14, 2014
    Rating Assembly

    I have made some progress but have not had time to posting the results.


    Since the pendulum rod is round, we need a way to keep the bob from rotating and hitting the case or weight. Several ideas were drawn up, but this is what I ended up with. A flat will be milled on the pendulum rod threads that will serve as a type of key to hold a special "bob seat" from rotating. Not sure if bob seat is the correct term, but I had to call it something.


    Milling the flat in the threads required a way to hold the rod without destroying the threads. To do this, a brass nut was made and screwed onto the end of the rod. A clamp could then be placed at each end of the threaded area like the photo below. I later moved the right clamp closer to the threads, but the thin area still wanted to flex a bit, so light cuts were required. The brass nut was then screwed farther up the threads so the flat could be milled all the way to the end of the threads.
    DSC_3642.jpg

    The bob seat was made from a solid piece of brass with a milled tapered slot that was eye-balled to fit the bob. The hole in the center was drilled under size and then filed for a slip fit over the pendulum rod threads with a coresponding flat spot. The flat spots keep the bob seat from rotating which in turn keeps the bob from rotating. Here are a couple of photos of the parts and assembly.
    DSC_4577.jpg DSC_4587.jpg


    The rating nut is nothing fancy, but it did offer an opportunity to experiment with rope knurling. Rope knurling is the correct look for old clocks but these knurls are nearly impossible to find and very expensive when you do. Diamond and straight knurls just do not look right so I was encouraged when I found this thread on the Practical Machinist forum where Larry Vanice makes a rope knurl with a single diamond knurling wheel. Before making a hand-held knurler like the one shown on PM, I improvised by removing one wheel from the QCTP knurling tool and clamping a 1/2" square bar in it for a handle.
    DSC_3092.jpg


    This was done on the big Atlas 10" lathe as I had to push very hard to form the knurl. The end of a brass rod was machined down and the end was rounded with a file. I put a piece of pipe in the tool holder for a tool rest. The knurl was then pushed straight in with the lathe running very slowly; about 30 RPM with cutting oil for lubrication. The first try did not turn out very well, nor did the second. The third time I decided to mount the knurl holder on the tool post and turn the lathe by hand until the knurl tracked correctly. The diameter of the work needs to be a multiple of the knurl size for proper tracking. The lathe was then turned on and the knurler, still on the tool post, was fed straight in until the pattern was fully formed in the brass. I then went back to hand held mode and slowly worked the knurling tool around the curved surface on each side to complete the rope. The import knurling wheels are not very sharp or smooth, so perhaps a better knurling wheel will produce better results. It's not perfect, but I did not need to buy a special knurling wheel and it looks better than a diamond or straight knurl.
     
  39. caddwg

    caddwg Registered User

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    Re: Rating Assembly

    Alan: Thanks so much for your continued postings along with the great photos and explanations. I've been building a regulator myself, so I'm always referring to your postings. Thanks again and continue the good work. Best Regards: Larry
     
  40. Allan Wolff

    Allan Wolff Moderator
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    The Weight

    With the pendulum finished we will move back to the weight.
    To maximize the drop, I will be using the design with the pulley inset into the top of the weight, this is the weight on the right hand side in post #76.


    This design makes the pulley extremely simple, but leave it to me to find a way to make it complicated. It is made from a 1.25" diameter brass bar. A round-bottom groove for the cable was cut with a profile tool and a center hole was drilled and reamed to provide a press fit for the ball bearing. 5 spokes were marked out with the index plate and the pulley was sliced off with a parting tool. I thought it would look nice if the spokes were inset from the hub and outer ring. This little detail made it very difficult to file and sand the spokes after they were sawn out. It does look better though. The center pin is simply a short length of 1/8" rod with the ends rounded. A dab of Locktite holds the axle in the bearing. Here is the finished pulley.
    DSC_4590.jpg




    There must be a law that says if something is simple, something else must be complex. In this case, the simple pulley requires a complex weight assembly. The end caps are cut from 3/16" thick brass plate and will have a finished diameter of 2.75" The caps were rough cut and stacked on a make-shift arbor and turned to size all at the same time one time.
    Weight Caps-Rough.jpg


    The caps were then separated and a groove was cut in each edge so the caps would fit halfway into the tube. The center hole in the bottom caps were tapped with a 1/4"-20 thread. The top caps require quite a bit more work to accept the pulley.
    A slot was milled a little wider than the pulley and longer on one side so the pulley can be installed. A cross slot was milled for the pulley axle to pass through. A similar indention was milled to hold the axle centered in place after it is installed.
    DSC_4592.jpg


    Installation of the pulley is easy. The pulley is held by the top edge and the axle is passed through the slot, moved to the center and lifted up into the indention. Now I need to find a way to tie the caps, lead weight and tube together. One method would be to thread the edges of the caps and a corresponding thread inside the tube. However, I do not trust my abilities to cut threads like this that will support the weight and am also concerned about the finished appearance. I'll cover my solution in the next post.
     
  41. Allan Wolff

    Allan Wolff Moderator
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    Re: The Weight

    Typical weights have a rod running through the center connecting the end caps. The pulley in the top cap makes this impossible. Instead, I added an internal disk. This creates a separate chamber for the pulley and provides a means of connecting a centered rod from the lower cap through the lead weight to the internal cap. The internal cap is connected to the top cap with 2 flush-mounted screws; one on each side of the pulley. Here is the general assembly. The center rod is simply 1/4-20 all-thread.
    DSC_4597.jpg


    The pulley chamber uses a lot of space that I would like to put to use. A slug of alumunum is shaped to represent a smaller cavity for the pulley. the slug is mounted to the internal disk and wrapped in alumunum foil. Aluminum from a soda can is wrapped around the internal disk and held in place with a hose clamp. Here is a photo of the makeshift mold. Behind the mold is the lead weight from the first pour and a slug of raw lead that will be used to make the second pour.
    DSC_3577.jpg


    Lead is then poured into the mold. The slug was wrapped with foil so it could be removed from the lead. Holes were then drilled through the lead and internal disk to fasten them to the top cap. All this extra work allowed about a pound of lead to be added to the otherwise wasted space around the pulley.


    Lead slugs will fill the remainder of the tube. The inside diameter of the tube is 2.5" A 12 and 16oz soda (or beer) can has a diameter of 2.6" so they make excellent molds for the weight inserts. (I seem to be drinking a lot of soda, or beer, on this project!) After the cans are filled to the desired level with lead, the aluminum can is peeled off and the lead is turned to size in the lathe. I made one large insert and several smaller ones so the weight can be adjusted.
    DSC_3597.jpg


    Lead machines about like it drills. A sharp tool with lots of rake works best, similar to a tool for aluminum. A heavy cut at slow speed seemed to produce a pretty good finish. Light cuts and high speed create too much heat which makes the lead gummy and sticky. Here is a photo of the various parts of the weight, less the pulley and center rod.
    DSC_3599.jpg
     
  42. tom427cid

    tom427cid Registered User
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    Re: Bob Weight Test

    Hi ALan
    Just a quickie-I have been following your progress-standards to live up to. Anyway,when drilling or filing lead I use the anti-spatter spray for mig welding on my cutting tools.file clean-up is easy.Even with a vixen file.
    HTH
    tom
     
  43. Allan Wolff

    Allan Wolff Moderator
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    Re: The Weight and a Question

    Thanks for the tip on the anti-splatter spray Tom. I will check into that.


    I would like to pause a moment and thank everyone for your suggestions and comments on this project. I am making some of this up as I go and appreciate any guidance I can get. It is also nice to know that someone is actually reading these posts. Thank you!!!


    Before moving on to the next part, here is a photo of the completed weight (still need to polish) with the pulley and cord installed.
    DSC_5753.jpg


    I have a question regarding the cord I am using. Originally, I planned to use 85 pound test fishing line for the cord. With the compound pulley, the line will only see half of the total weight, or about 8 pounds. However, the fishing line is very thin and twangs like a guitar string when the weight is hung. I did not have much confidence that it would hold up over years of usage, so I replaced the fishing line with this Kevlar Braided Cord


    This cord is really great! As you can see in the photo, it is a dark gray or black color and should look good with the clock. It is very flexible and does not have any appreciable memory. For example, when it is wound around the drum, it stays wound even without any tension. We all know how fishing line and metal cable will "bird's nest" around the drum and get tangled on itself. It also appears to have little or no stretch. I have not tested its 200 pound rating, but have little doubt it can hold a lot of weight.


    So here is my question: Is anyone aware of any problems with Kevlar supporting a continuous load? Granted that a cord rated at 200 pounds should not have any problems supporting 8 pounds, but what will happen after 5, 10 or 20 years. I am curious about how it will hold up over time. I am very interested to learn more.
    Thanks,
    Allan
     
  44. harold bain

    harold bain Registered User
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    Allan, I suspect many of these modern cords just haven't been around long enough to have passed the test of time. I still use gut line in tall clocks, as traditionally used. I do use braided fishing line in other weight applications such as Vienna regulators, without any problems yet. If it loses half its rating in 30 years, down to 100 pound test, there is still plenty of strength left for this application.
     
  45. Allan Wolff

    Allan Wolff Moderator
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    I agree Harold. After some additional searching, I found this Technical Guide on the Dupont website (Dupont is the manufacturer of Kevlar.) On page 4 is this very encouraging paragraph (I added the underline):

    Stress Rupture
    Stress rupture is the sudden failure of a material when it is held under a load less than its tensile strength. For practical purposes, stress rupture is measured under a constant load that causes the failure to take place over relatively long periods of time. The greater the load, the more quickly failure occurs. However, even the smallest load could theoretically cause stress rupture if enough time were allowed. Figure 6 is a plot of log time to break versus load, expressed as a percent of the ultimate tensile strength, for KEVLAR ® , nylon, and polyethylene. For KEVLAR ® ,
    loads below 50 percent of the ultimate tensile strength are of no practical importance, since stress rupture failure would only occur after more than a century.

    So, unless some other information about Kevlar comes to light, I will just leave a note in the clock to change the cord every hundred years.
     
  46. Allan Wolff

    Allan Wolff Moderator
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    The Bezel

    The bezel and dial pan are next. The bezel proved to be extremely difficult, frustrating and even physically exhausting. This may be a bit long winded, but hopefully you will enjoy reading about our struggles and learn from our adventures and mistakes.


    If you study Vienna Regulators, one of the things that stands out is the variety of bezel designs used throughout their history. Some appear to be stamped from brass sheet while others appear to be turned on a rose lathe or other equipment to machine decorative patterns into the surface. I would love to know more about how they were made. However, I have none of this equipment so an alternate method is needed. I found an interesting January 2009 BHI article by Rex Swensen about making a bezel from a solid brass square bar.


    I had my doubts about duplicating Rex's method for bending the bar and he does not give a lot of detail on the bending process. I also wanted a wider bezel than the 3/8" design he used. A 60" long 3/8" high x 1/2" wide brass bar was ordered, enough for two bezels. A ring roller is the proper machine to make smooth, round objects from straight stock. There are quite a few industrial shops around Tulsa, so I figured one of them could quickly run my bar through their machine and hand me back a hoop with the exact diameter specified. The manager at the first shop looked at my drawing for about 10 seconds, handed it back to me and said, "My machine won't handle material this thick. Plus you want it rolled the hard way", meaning rolled along the 1/2" dimension rather than the 3/8" side. "You might try the shop down the street", he offered. Unfortunately the shop down the street said almost the exact same thing.


    Not to be discouraged, I decided to make my own ring roller. Here is what I came up with.
    Ring Roller.jpg


    The jaws are removed from the bench vise and this gadget is installed in their place. The rod is pushed through the rollers and the vise is tightened a little more with each pass. In the final design, I replaced the single roller with a large bolt that could be turned with a wrench to drive the bar through the roller. I ordered some needle bearings with 2100 pound static load rating and used 1/2" drill rod for the pins for the bearings. It took a couple of hours to make the roller once the material arrived.

    During our next session, my friend and I start rolling the brass rod. We heated the rod with a Mapp torch to anneal it as much as possible. Here is a photo of the first pass.
    DSC_3601.jpg


    I am pretty proud of myself and my homemade ring roller; this is going to be easy! An hour and a half later, we are at this stage and facing a multitude of problems. (Optimistic people would call them challenges, but we are way beyond being optimistic.)
    DSC_3602.jpg


    The bearings stopped turning on about the 3rd pass. Apparently 2100 pounds was nowhere near robust enough for the pressures we were applying with the vise. In addition to turning the bolt, we are having to push the rod through the non-rolling rollers. Sometimes the bench starts to tip with the force we are using to move the rod. The drive bolt has developed a habit of screwing itself out of the bracket regardless of the direction turned. Why does it always come out rather than hold itself in? Of course I did not see a need to provide a fastener to hold the bolt in, the threads have been cut off, so we stop and hammer it back down every few turns. You will also notice that as the hoop has begun making its second loop, the previous loop must be steered over or under the roller. It's like wrestling a python! We tried annealing the rod again, but this was no help at all. We are both exhausted and need a new plan.


    So its out with enginuity and in with brute force. We first mark the brass rod every inch. Line up a mark with the drive bolt, tighten the vise, loosen the vise, move to the next mark and repeat. After a complete pass, we tighten the vise another half-turn and go around again. This is slow, but actually works quite well. It takes a lot of force to bend the rod and I am surprised the Harbor Freight vise does not break under the strain. However, there is a mysterious pile of cast iron dust under the vise.


    Finally, after 3 hours the bending is complete! Our 5 foot long brass bar is now rolled into a 9-inch circle. Somewhere in that coiled up monster are 2 beautiful bezels waiting to be discovered. They are going to have to wait though, because we are too beat to go any further. Clockmaking is not a hobby for wimps!
    DSC_3604.jpg
     
  47. Allan Wolff

    Allan Wolff Moderator
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    Re: The Bezel

    With the muscle work out of the way, we can focus on converting the coil of brass into rings. The coil is the size we need, 8.25" inside and 9.25" outside diameter, so it can be cut straight through with a hacksaw. The cut is made so the straight end pieces are removed, leaving only the round part. The ends are filed and the coil is bent to remove the spiral so the ends fit flat against each other. There is a little gap, but the brazing specifications actually recommend a few thousands gap so the filler rod will flow. The ends are held in position with soft steel wire.
    DSC_3643.jpg


    The ends will be silver brazed instead of soldered. Silver solder melts at about 350 to 600 degrees F and has a strength of about 3000 psi. Silver brazing is performed at 1200-1600 F and has a strength of about 40,000 psi or higher. The Speedy Metals website lists the tensile strength of 360 brass as 58,000 psi and yield strength as 45,000, so the silver braze should be nearly as strong as the metal itself. Although external forces will not be applied, there will likely be thermally induces stresses that could break a soldered joint.


    I chose to use Harris Safety-Silv 45T silver brazing rod for several reasons. It contains 45% silver and some tin which lowers the melting point to 1195 F so it is below the recommended hot working temperature of 1300-1450 F for 360 brass. The color is stated as silver to bright yellow so it should blend in well with the brass. Stay-Silv white brazing flux was applied to the joint before heating. The ring was placed on ceramic fire bricks and a small piece of brazing rod was put on top of the joint as a temperature indicator. Heat was applied with a mapp torch a few inches on each side of the joint area, with most of the heat focused on the bottom side of the joint. When the small piece of rod melted and flowed into the joint, I applied heat for a few seconds longer, then removed the torch and applied more brazing rod to the joint. Here is the finished job. I used citric acid in water (we use citric acid to clean our dishwasher) with a toothbrush to remove the flux.
    DSC_3645.jpg


    There is a small out-of-round point where the ends meet, but that will be machined out next.
     
  48. Allan Wolff

    Allan Wolff Moderator
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    Re: The Bezel

    Sometimes the tricky part of machining something is figuring out how to hold it. Since the ring needs to be machined on all four sides, multiple setups will be required.


    We start by machining the outside and back of the bezel. A plywood disk is mounted on a faceplate with a smaller plywood disk mounted on the front of the first disk. Both are turned round and then the smaller disk is reduced in size until the ring fits snuggly over it. Snug is important since no glue, fasteners or clamps are used to hold the ring, just friction. Here is an action shot of the setup. The camera flash freezes everything except the mounting screws.
    DSC_3647.jpg


    Here is a view from the other side. Note how close the large wood disk is to the lathe bed. This is a 10" lathe and there is less than an 1/8" of clearance. Also note how the top slide is turned around so it faces away from the center of the lathe instead of in. This is so the tool bit can reach the outside edge of the bezel. Any larger bezel would not have fit on this lathe.
    DSC_3646.jpg


    Only enough material is removed from the outside of the bezel to make it round. The face is then machined, again removing only enough to make it flat. Very light cuts are taken so as not to dislodge the bezel from its friction fit. Next the face is cut with a .04" deep inset for the dial pan, allowing the pan to fit flush and be invisible when viewed from the side.
    DSC_3649.jpg


    The small wood disk is now removed and a groove is cut in the large disk so the bezel will fit snuggly inside and protrude slightly above the face. Again, friction on the outside edge holds the bezel in place. the bezel face is then machined until flat. Machining the inside edge requires some of the wood disk to be removed to make room for the tool as shown in the close-up photo below.
    DSC_3651.jpg DSC_3650.jpg


    A bevel is then cut with the top slide set at an angle to remove excess material before final finishing.
    DSC_3822.jpg


    Now the artsy part begins. I wanted an attractive detail that was within my limited equipment and abilities. I did not take any photos of the work in process, but you should get the idea from the finished photo. Starting at the outside of the ring, I left the flat area 1/8" wide and then cut the bevel about 1/16" deeper. Another flat area a little over 1/16" wide was cut along the inner edge. A half-round profile tool was then used to scrape (turning the lathe by hand) the outer edge to a rounded profile. For the final touch, I brought out my newly-made knurling tool equipped with a BFH (Big Fat Handle) and a good quality knurling wheel to create a rope knurl around the outer edge. Knowing that this would be difficult to polish later, I went ahead and lacquered the bezel while it was still bright.
    Bezel Profile.jpg


    One final note. The brazed joint is not visible. I looked for it under magnification and cannot find any trace of it; probably a combination of the color of the brazing rod and machining of the brass caused metal to be drawn over the joint. I hope it stays invisible as time passes and the finish ages.
     
  49. John MacArthur

    John MacArthur Registered User
    NAWCC Member

    Feb 13, 2007
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    Re: The Bezel

    That all looks terrific, Allan! Do you have the movement running yet?

    John MacArthur
     
  50. Allan Wolff

    Allan Wolff Moderator
    NAWCC Member

    Mar 17, 2005
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    Tulsa, OK
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    Re: The Bezel

    Thanks John.
    I have the motion works built and will document the results here very soon. The movement ran for about 8 days to confirm there were no issues and it is currently torn down for final clean up and finishing. We have also started on the case, so I am hoping to have everything completed in a month or so.
    Allan
     

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