Owner built precision regulator

[jhe.1973]

Hi Everyone,

Thank you Allan for your invitation to post & discuss my clock on this forum.



I have a brief description of the prototype clock on my web site at:

http://www.jim-haubert.com/id7.html

But here are a few better photos:





This clock is a prototype that I built for the purpose of trying ideas that I had been kicking around. I was/am hoping to market some type of precision clocks and I needed to learn where my time would be most productive.

There was plenty of opinion, but I was unable to find precise evaluations of many of the accepted practices. I.E statements were common that hard pivots had less friction than soft ones, but just HOW much less were the type of details I was looking for.

The lessons I have been learning have resulted in my designing the movement pictured below - still awaiting completion.



As I developed the prototype, an idea occurred to me to fix the great wheel firmly on it's arbor (rather than have it float) and wind the drum w/teeth cut into one of the flanges. I rigged up the prototype this way, but I don't have a photo handy. This method of winding shows up in the photo above.

The winding arbor is spring loaded to keep it from adding friction to the train. To wind, you just push the key/crank in to engage the gear w/the drum teeth and wind the weight up. Release the key/crank & the arbor pops back out of engagement.

I've never seen this method before or since but it allows the great wheel to be as concentric as possible to the arbor rather than 'kicked' off to the side by the action of a ratchet pawl on one side.

There are a number of other breaks I made w/tradition (that I feel are improvements) but I will just have to keep posting additions to this thread as I get time.

If there is enough interest, I promise to post more details w/photos explaining the entire process I have been going through.

But for now this is my start.

Best wishes to ya'll.

Sincerely,

Jim

 

[bkerr]

Very interesting, keep the information comming. Someday I too would like to build one from scratch. How did you go about making the gears. I have a couple of lathes and a Bridgeport but I am not fully tooled up with a dividing head ect. At least not yet!

Great stuff

 

[John MacArthur]

Jim -- I'm curious about what appear to be bi-metal wheels. Are they, in fact, made of two materials? If so, what are the inner rim, spoke, and hub assemblies made of, and is there a reason for this, other than aesthetics?

Thanks for posting these pics.

Johnny

http://laplaza.org/~jmac/

 

[jhe.1973]

Hi Everyone,

Thanks for your interest & kind words!

Johnny:

The gears are some type of bronze w/aluminum centers. How’s that for being specific?

When I did this clock I was waiting for a job to arrive so I scrounged around the shop to use whatever I could in a hurry while I had the down time.

The bronze was from some tube ends my brother-in-law gave me & was rather tough cutting.

I did thin the wheels down a few times to see what effect each thinning had on the power loss within the movement. That’s when I had to pin the hour hand wheel rim to prevent slipping.

bkerr:

If you already have a B-port & lathes you are miles ahead of some of craftsmen of a couple of centuries ago that still built fantastic clocks.

Not having a dividing head only changes how you cut gears, it doesn’t mean you can’t. All you really need is an index fixture and a flycutter. Fly cutter bits can be ground by hand.

Here is an index fixture that my Dad made years ago & it works just fine. All simple lathe & mill work to make it.



As far as the index plate on the end, you should be design it to substitute a gear that has enough teeth for your wheels & if you design the train for it, the pinions can be an even number taken from the same gear.

I did use a dividing head & B-port for the prototype pictured here. But for the second movement above I made a different setup for a bench model horizontal mill & indexed the same way as my Dad’s fixture.

Have you read, "The Modern Clock" by Goodrich? Written in the early 1900s it has a lot of good suggestions about building your own regulator. Some so/so opinions too, but overall inspiring.

For all of you that are viewing this thread:

The dial started out as the lid to a 55 gal. drum, the pendulum tubes were kitchen sink drain tubes, the pendulum shaft was a curtain rod & the wood came from maple door trim I salvaged from a house torn down across the street from where I was living.

Oh yeah, I just remembered, the plates for the movement aren’t brass. I used aluminum there too. I polished it, installed Bergeon bronze bushings & painted them w/tinted lacquer to look like brass. Has fooled everyone so far!

I’m saying all of this to help shake up anyone who wants to build their own clock into realizing that you don’t have to wait for the right equipment, or even the right material. This isn't meant to be critical, just helpful prodding.

Get creative & see where it leads.

Best wishes to ya'll.

Sincerely,

Jim
　

 

[jhe.1973]

Hi Everyone,

I need to apologize for not posting for awhile. Besides being rather busy, I didn't see new posts here & never thought to check the views this thread received.

DUH!:bang:

I just came across a rough draft of an article I was going to send to the NAWCC Bulletin about the winding method I came up with and as I was trying to adapt it for this thread I decided to start at the beginning:

In 1979 I owned an R&D machine shop and was doing clock repair as a sideline. Precision clocks have always interested me but were beyond my reach financially so I was considering building my own.

As I studied more literature, it became apparent that I would have to build my own prototype movement to answer questions I had concerning traditional methods and designs. Most of my questions had to do with reducing friction and loads that contribute to friction.

So in January I started with a concept and developed it into the completed prototype the following March. I have been making and evaluating numerous changes periodically ever since.

I took a flying guess as to how wide to make the 120 teeth on all of the wheels. Starting with a cutter for woodruff keys I ground the tooth form I had come up and used the same cutter to make the pinions which have 15 and 16 teeth.



First mistake/surprise, but also a lesson.

Not only are the pinions supposed to have quite a bit of backlash i.e. thinner teeth, wider spaces, but the thin shank of the cutter right behind the head allowed it to flex as it entered and left the wheel blank. The result was a very slight curve to each tooth.

In order to get the movement to even run, I ended up filing all 360 teeth of the wheels to get them to mesh smoothly. It wasn’t a lot of material because I was only taking the high spots off the curve, but it was still time consuming.

The lesson was quite valuable though in that it taught me the importance of rigidity in the milling operation of precision teeth.

At first I wasn’t going to build a case, just run the movement on a test stand. It quickly became apparent that I would need a cabinet to keep the air movement in the room from disturbing the pendulum.

This was my second surprise because I had been running movements I repaired on my stand for years. However, I was now trying to accurately track a precision clock’s performance and it was a whole new ball game.

Once the case was finished I was in for another surprise.

Comparing my clock to a 110 volt AC electric clock with a sweep second hand I was quite taken back at how much my clock varied during the day. That was until I bought a Timekube from Radio Shack that picked up the WWV time signals.

SURPRISE! My clock was within a few seconds per day right off the bat but the 110 volt clock varied as much as 20 or 30 seconds in a few hours.

New lesson for me, the electrical grid’s voltage varies a lot during the day although it averages out more or less it sure isn’t a regulator.

Next, I’ll discuss the details of my winding method and the surprises that led to.

 

[Lourival]

This is agreat post.I am very interested in this work. Congratulations!

 

[kdf]

Very interesting, very nice!

Btw., electric clock depends on frequency rather then the voltage.

 

[jhe.1973]

Hi Everyone,

kdf: Thanks for pointing out the frequency issue. I should have remembered that, especially with VFDs being all the rage these days.

I should have mentioned a detail that led to another mistake in my last post.

I had still had to make the escapement when I took the movement to the person I learned clock repair from. He let me borrow “The Modern Clock” by Ward Goodrich until I could purchase my own copy. I hadn’t seen the book before.

This allowed me to accurately design the escapement, rather than take another flying guess as I did with the gear teeth.

Once the clock was running in the cabinet, I made a beat plate to track the amplitude of the pendulum. This led to the discovery of the next mistake.

I had laid out the escapement just as Goodrich suggested, starting with 4 degrees pendulum swing and dividing it by 2 to give 2 degrees lift to each pallet. But I was only getting a little over 2 degrees total swing.

I recalculated my divisions on the beat plate using both the length of the pendulum as the radius of a circle then dividing the circumference by 360 and using trigonometry to figure the distance of the angular displacement. Both methods came out the same.

Couldn’t figure out where I had gone wrong until I watched the escapement while I slowly moved the pendulum by hand.

While one pin is wiping across the 2 degree lifting surface of the first pallet, the second pallet is moving into engagement to catch the next pin. Therefore each pallet only reverses the same 2 degrees of travel – they are not added as Goodrich suggested.

Bingo! It wasn’t my mistake, it was his!

I have run into this repeatedly during my R&D career. People state opinions as though they are facts and often don’t even realize it.

Now why do you suppose I felt I had to build my own movement?

Let me make something clear here. I still highly recommend ‘The Modern Clock” for it’s wealth of information. It just shows that we all make mistakes and advice should be considered a guide, not the last word.

Including mine.

Now for the promised details of the winding method I developed. I had never seen this method before or since so I think it is unique. If so, this is an opportunity to be recognized as its creator.

I was/am concerned with the smooth, accurate transfer of force at each step in the gear train but particularly at the early stages.

With conventional winding arbors, the winding drum is firmly fixed to the arbor requiring the great wheel to be a slip fit on the arbor. The small clearance at the shaft will allow the wheel to move slightly sideways when the click locks the drum from unwinding. This clearance at the arbor will be magnified out at the wheel teeth creating an eccentricity.

In my prototype, the great wheel turns once in 8 hours giving a long opportunity for any eccentricity to affect the force transmitted into the train.

It struck me as odd that so much attention has been paid to gearing in precision clocks, but so often a method is used that can introduce an error right at the start.

To avoid the possibility of this error, I mounted the great wheel firmly on the arbor but then had to come up with a way of winding the drum. That’s when the idea hit me of cutting teeth in one of the flanges and use a gear mounted on another arbor to turn the drum.

The next idea, to spring load the winding arbor so that it would have no drag on the train, quickly followed the first.

The following photos show this setup in the prototype:



You can see that it was an afterthought as the bronze bearing blocks are cut through the sides of the plates that had already been made. But that’s what prototype is for.

I am reminded of the following:

"If we knew what it was we were doing, it would not be called research, would it?"
- Albert Einstein

Once I completed this winding method three more advantages became apparent.

First: The great wheel pivot holes in the plates will have half the wear. In 8 days this great wheel turns 24 times. If wound conventionally, the arbor would be turned backwards the same 24 turns. Instead, only the drum is turned 24 times, not the entire arbor.

Second: Partly due to less wear, but largely due to no winding square, both pivots can be the same size and only large enough to supply an adequate bearing. By being the same size they have the same frictional drag. This eliminates a slight twisting moment or force as the arbor winds down due to unequal friction at the ends.

Third: It is now possible to fit endstones to both ends of the winding arbor. This led to a big surprise for me. When I fit glass endplates to the winding arbor, I picked up over ½ inch of travel in the seconds pendulum weighing over 30 lbs. and already traveling over 2 ½ inches.

No other refinement before or since yielded as much. In the second clock movement I am using sapphire endstones because of their increased hardness.

Still more to come along with more surprises.

 

[neighmond]

Where do you get your jewels?

 

[Rob P.]

Wonderful project. I too would like to someday build a clock from scratch.

A question regarding dividing heads: On every lathe I've ever seen there is a backplate to the chuck. Why hasn't anyone put worm-drive teeth on the edge of the backplate so that a wormdrive screw/handle can be fitted to the lathe bed? If the chuck also had degrees etched on the outer surface, you could just turn the crank on the worm and (using a pointer) get perfect degree divisions for ANY tooth count. Or am I missing something here?

I don't have a lathe of my own and I use a friend's Southbend Heavy 10 (Yep, even for making teeny tiny bushings, arbors, and other stuff) whenever I need to machine something so I can't experiment with hobbing a backplate. But from what little I know, it should work and would be a ton less expensive than a dividing head. And, since the teeth are cut into the center of the backplate rim, there isn't anything sticking out to catch/bite you.

So, like I said, what am I missing here?

 

[jhe.1973]

Hi Everyone,

Thanks for the interest in this thread.

neighmond:

Regarding my purchase of the jewels, I bought them from Bird Precision back in 1983. They had a minimum purchase price back then IIRC was $150.00. An engineer I talked with was interested in my project and he agreed to send just a small sample of the 7 different sizes/styles I needed for the purchase minimum. Otherwise I would have had to spend the minimum price for each size/style.

If you do an internet search you will find several different suppliers and perhaps someone will be more willing to deal with selling just a few that an individual might need.

Rob P:

I don't think you are missing anything. I am sure that your idea would work just fine. Are you aware of the dividing attachments that individuals & companies have made that fit the opposite end of the lathe spindle from the chuck?

My basic workhorse lathe is a 16in Southbend & I used that to turn a balance staff for a French clock I was repairing. I did however use a watchmakers lathe to finish the .005 dia. pivots. THE SB is just too slow for that small a diameter.

Check out Jay Fortner's posts #s 11, 13 &15 on this page. He very cleverly 'indexed' the lathe spindle and used the carriage assembly as a shaper to cut gears.

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

 

[tok-tokkie]

Congratulations on a fine looking clock. The precision required in the gears to get low power and consistent running is something that really distinguishes regulators from ordinary clocks. The less the required drive weight the better the clock. To get one to run 30 days with not much weight falling not very far is the mark of exceptional work. Vienna regulators really impress me.

I like the look of your wide composite gears.

The endstones are on the Great Wheel arbor are they not. The winding arbor is spring loaded so it can slide out of mesh when the clock is not being wound.

I look forward to the next episode. I too am making a clock but with Hygens endless loop drive as i wanted to sidestep the maintaining power complications but it has not worked well & I am busy with something else so have not progressed it for a while. Hence my particular interest in what you are doing.

 

[jhe.1973]

Hi Everyone,

tok-tokkie:

Thanks for your kind words.

The endstones age indeed on the great wheel arbor & the winding arbor does slide out of mesh once the winging crank is released.

It is great to hear that other builders are following/interested in my experiences.

I've had some setbacks over the years (one serious), which I will be describing as I can find the time to post more of this story. So, I can understand when you mention that something might not have worked as well as anticipated, but I hope that you don't let that affect your enthusiasm.

 

[jhe.1973]

Re: Owner built precision regulator - the beat goes on - pun intended!

Hi Everyone,

I spent a few hours cleaning my prototype movement so that I could run a test of the Nano oil I bought recently. This gave me the opportunity to get a few photos of details that I want to discuss.

Before I get to that though, I want to mention my next big surprise that I found back in the early days of my project.

I had planned to use brass cable for the weight because I have always liked the looks of brass cable in the various clocks that have crossed my bench. Because the movement was apart as often as it was together, I just grabbed some braided nylon chalk line I had handy and used that in the beginning.

After a few weeks, once initial bugs were worked out and the movement was running well, I pulled it apart to put in the brass cable.

I couldn't get it to run again!

Apart & together a few times to try and find the problem and I was coming up empty handed. That was until I tried only one turn of cable on the drum.

What you say? Me too!

I found that as I wound more turns on the drum of the brass cable, the movement would lose power in proportion to the number of turns on the drum.

Pulling it apart once again, I found that the cable had a fairly fine steel (perhaps music wire) core and it was acting the same as winding a spring and robbing the drum of torque.

Perhaps.

I also considered that if it acts as a spring, it could be creating a side thrust on the winding arbor creating more friction that way. This was before I had installed the endstones, by the way.

Whatever the reason, I figured that it was a variable I didn't need and went back the the nylon line.

Tonight, as I took the movement apart, I realized that I have another break from the movements I have seen so far. Rather than use small pins to locate the bridge for the verge, I intentionally made the movement narrow at the top so I could have the same hollow dowels in the top posts, locate the bridge.



Because the verge arbor is a fulcrum for the impulse I felt that this was a more reliable way to, not only locate the bridge, but to more rigidly tie movement together.

I have taken this approach further with my second movement as I will show when I get to discussing that one.

 

[jhe.1973]

Re: Owner built precision regulator -oops! I meant to include this in the last post.

This is a photo of the movement as I was assembling it tonight.



I wanted to show the white timing dots I have at each meshing.

Remember I said I had to file the teeth? This is to show that for all these years I that I have run the clock, I have always had to assemble it in this manner to assure smooth meshing.

This wouldn't have been necessary if I had cut the teeth correctly in the first place!

I'm trying to encourage ya'll to not be afraid of making mistakes. That's why I won't try to hide any of mine.

I also get a laugh from the thought that, someday, someone will take this movement apart and cuss me out until they figure out how to get it running!

 

[kdf]

Re: Owner built precision regulator - the beat goes on - pun intended!

Pulling it apart once again, I found that the cable had a fairly fine steel (perhaps music wire) core and it was acting the same as winding a spring and robbing the drum of torque.

Perhaps.

I also considered that if it acts as a spring, it could be creating a side thrust on the winding arbor creating more friction that way. This was before I had installed the endstones, by the way.

I doubt this is the reason. I used steel cable (0.7mm) on few clocks which is very elastic, and didn't noticed anything unusual. Clocks always run the same, regardless of number of cable turns on drum. Elastic force is too small (compare to weight) to make any disturbances, at least in my case.

 

[jhe.1973]

Re: Owner built precision regulator - the beat goes on - pun intended!

I doubt this is the reason. I used steel cable (0.7mm) on few clocks which is very elastic, and didn't noticed anything unusual. Clocks always run the same, regardless of number of cable turns on drum. Elastic force is too small (compare to weight) to make any disturbances, at least in my case.

Hi Everyone,

kdf:

You may be right to doubt my suggestions for the reason I could not keep the clock running w/brass cable.

My prior experience is the same as yours, where the weight cables in the various clocks I have worked on through the years wasn't an issue.

However, once I was trying to keep a heavy (30+) pound seconds pendulum swinging with as small a weight as possible, there were many cases that my past experience didn't seem to apply.

After four tries to get the movement running with the brass (each time between it would run with the nylon) I accepted the results and moved on.

I will probably never know the exact reason for the brass not working out. It remains one of life's great mysteries. o

 

[kdf]

Re: Owner built precision regulator - the beat goes on - pun intended!

How heavy is weight? (Sorry, my English is not very good.)

 

[jhe.1973]

Re: Owner built precision regulator - the beat goes on - pun intended!

How heavy is weight? (Sorry, my English is not very good.)

When I first got the movement to run it required 10 pounds w/pulley & double line. It is now down to 7.9 on the double line and it looks like I will be reducing it some more to bring the pendulum travel back down to where I prefer it to run.

Your English is fine for me. I don't feel you need to apologize.

 

[kdf]

Re: Owner built precision regulator - the beat goes on - pun intended!

Strange. On clocks where I used steel cables, weights are 1,5 kg (cca. 3.3 pounds) and I did noticed anything unusual. What was diametar of these brass cables?

 

[Tinker Dwight]

Re: Owner built precision regulator - the beat goes on - pun intended!

Hi
I can't think of anything that would act like that. I'd
more likely suspect the cable getting caught in the
grooves of the drum. Nothing that had to do with
the number of turns on the drum.
Maybe internal friction of the inner cable sliding
inside the external housing might change as
it wound and unwound.
Tinker Dwight

 

[jhe.1973]

Re: Owner built precision regulator - the beat goes on - pun intended!

Hi Everyone,

kdf:

I thought I might still have the cable I used but haven't been able to find it. I remember using some brass cable to raise & lower the electrode of an EDM machine I built over 12 years ago. I had to replace it for a rack & pinion & that might be when I lost track of it.

It seems to me that it was in the .040 - .060 inch range.

Tinker:

Just to supply a detail, this prototype has a smooth drum. This could mean that the coils were binding sideways of course.

I did remember something else though.

Whenever I would lift the weight on a clock with brass cable, the cable would unwind slightly from the drum showing that it at at least some tendency to act as a spring. Perhaps that is where I got the idea that this was an explanation.

I was never able to come up w/anything that completely satisfied me for an explanation & didn't have the time to deeply investigate it. It always seemed that if the cable was acting as a spring, it would supply more force as it was wound not less. However w/a wound spring, the anchor stays a fixed distance from the arbor (as in a barrel) and in this case the anchor (pulley) is always moving down.

Thanks guys for helping to brainstorm this detail and to everyone for your interest.

 

[jhe.1973]

Re: Owner built precision regulator - the beat goes on - pun intended!

I mentioned a few posts back that I had the chance to get some photos of details I want discuss.

This is a general view of how the movement & pendulum is secured to the case and wall:



The backplate and arms are 1/2 inch thick aluminum jig plate that I had on hand. The 5 flathead screws (1 is hidden by the pendulum) secure the mount to the case. The 2 nuts on studs at the top go through to an adapter that is fastened to 2 wall studs.

Originally, these studs were 3/8 lag screws that went right into one stud and the lath & plaster right next to it.

It may sound strange that I picked up the lath for one of these mounting points, but when I built this clock we were living in a rather large Victorian house that was rather sturdy. All outside walls & interior load walls were 2X6s when they still used full size lumber. Every load wall rested on 8 inch square wood beams, on top of 2 foot thick fieldstone foundation walls. The lath I mentioned was a full 1/2 inch thick and the plaster was at least that. Being in Wisconsin the stone walls went at least 4 feet into the earth which was dense clay at that depth.

When the clock case was bolted to one of these walls, in the evening I could start the pendulum swinging w/o the movement and the next morning it would still have a very slight but noticeable swing.

Besides the backplate being bolted through the wall close to the pendulum anchor, there is another detail shown here that I feel helped achieve this kind of rigidity:



The suspension spring is mounted in a piece of 1 inch thick steel cut from a piece of hex bar I also had laying around. The two round disks on each side at the top of the suspension spring are captive in the slot for about 60 to 70% of their side surface. There is also no side shake at all at the top or bottom of the suspension spring. The spring will not fall into place by itself, it has to be pushed into place.

You can also see the safety hook assembly I made in case of spring failure. Because there is not much more than two degrees distance for the pendulum to swing, I have to reduce the weight each time I gain more pendulum travel due to successful experiments.

This house had a brick veneer and it heated and cooled slowly. I never built temperature compensation into the pendulum but during one particularly consistent temperature period in early fall, using the WWV signal as my reference, this clock kept time to 1 1/2 seconds over a three week period. I hadn't expected this because of the trouble I mentioned with the gear meshing. It taught me how much more important the pendulum mounting is and if rigid enough, a heavy pendulum can hide gearing sins.

One other thing. In the first photo above, to the left of the pulley mount there are two holes. These are earlier anchor trial points when the pulley simply hung from a hook. It is now on a ball & socket swivel joint.

I found that the mounting location for this pulley to be a contributor to end thrust of the great wheel arbor so it's location is somewhat critical.

 

[Tinker Dwight]

Re: Owner built precision regulator - the beat goes on - pun intended!

---snip---
I found that the mounting location for this pulley to be a contributor to end thrust of the great wheel arbor so it's location is somewhat critical.

Hi
This is more likely an explanation for the change with the hard wire. The friction between
turns on the drum would increase as it wound more.
With the softer line, the line can easily twist to kind of unroll from the adjacent turn.
Tinker Dwight

 

[jhe.1973]

Re: Owner built precision regulator - the beat goes on - pun intended!

Hi Everyone,

Tinker: Sounds good! You might be right. I just wish there were more hours in the day to investigate all the possibilities.

Years ago when we moved from the Victorian house I mentioned earlier, I made an adapter to pick up wall studs and bolt the clock between them.

We recently brought a new (to us) piece of furniture & I needed to move this clock up about 6 inches. The rust pattern on the wall from an old roof leak shows where it was. I also had a couple of shims at the top corners of the case to prevent sway.



Because the clock was partially covering a small exhaust fan & now would be right over the top of it, I welded a length of 3/4 inch square tube to stiffen the assembly and figured the shims would provide enough rigidity.

New surprise! It wasn't good enough, the clock wouldn't run.

Even with the top shims, there was too much flex along the bottom where the aluminum spacer is. So I made a new spacer that is about 1/2 inch taller & goes all the way across the steel sheet. There are two holes in the new spacer that line up with the lowest flat head screws in the above photo. These holes are now opened up for lag screws that go through the case and into the studs.

This spacer & lag screws also eliminates the need for shims at the case top.

See what fun swinging a thirty pound seconds pendulum can be?

 

[doc_fields]

Re: Owner built precision regulator - the beat goes on - pun intended!

Have you thought about using small stainless steel ball bearings rather than jewels? I know that jewels are fine and traditional, but I have noticed many European clockmakers using ball bearings now instead of jewels for the advantage of less friction. I did some experiments on one clock movement wherein I substituted these bearings for the usual bronze bushings, and believe me, there was quit a difference! Mark Butterworth sells them. I tried for a few years to locate some affordably, but he did a better job of it than I. I'm currently designing a movement now utilizing these all the way up the train. Here is a link for some idea of what they do with these:

http://erwinsattler.de/en/products/precisionpendulumclocks/metallica1735/index.php

Really appreciate your clock and what you have done with it........................doc

 

[jhe.1973]

Re: Owner built precision regulator - the beat goes on - pun intended!

Hello Doc,

Thanks for the kind words about this clock and for thoughtfully including a link to the Sattler web site. I’m glad you appreciate my efforts.

I find it interesting that you mention the ball bearings now because I recently added three, but I don’t think they are stainless steel.

When I first built the clock I just grabbed a repo #2 ST weight pulley that was lying around for the one at the top of the case:



FINALLY this last spring I got tired of looking at the X shaped yoke I had started 29 years ago for a clock that I have long since sold. I finished it for this one and put a ball bearing in the hub of the pulley:



While I was at it I made another pulley w/ball bearing for the top of the case and used the original yoke from the weight up at the top. That’s when I made the ball swivel anchor I mentioned earlier.

I had a noticeable improvement in power but didn’t measure it because right after that I mounted a ball bearing on the second arbor (which is the minute hand). I thought I had a better photo of the rear plate showing the aluminum bearing holder (red arrows) but this will have to do for now:



All told, these three bearings and a lubricant change allowed me to shorten the weight by 1.375 inches for a 1.75 pound reduction.

Before the ball bearings, I tested Valvoline Moly grease instead of oil. This was VERY promising on it’s own. But after about 6 weeks, there was a sudden reduction. It was then, as I was searching for a reason, that I found out that Molybdenum isn’t recommended for lubricating brass because it attacks it.

Oh well, it was great while it lasted.

I will probably try ball bearings on the great wheel arbor fairly soon, but am running a test w/Nano oil at the moment. W/Nano it is showing a similar power increase to the grease so I finally made a different weight shell for testing purposes. It is open on top so I can easily change the amount of lead shot and calculate the actual percentage of improvement.

 

[doc_fields]

Re: Owner built precision regulator - the beat goes on - pun intended!

You know, I may be mistaken about those bearings being stainless steel. I'll have to check with Mark on that. Will try to let everyone know on Monday or so...........................doc

 

[jhe.1973]

Re: Owner built precision regulator - the beat goes on - pun intended!

Hi Everyone,

Last month when I brought this thread back from the dead, I mentioned the article I had started. There is one more point I want to mention so I can clear my old notes from my desk (at least I still hope there's a desk under all this junk).

The only technical clock book I had when I started was Donald de Carle's, "Practical Clock Repairing". I focused on the chapters dealing with gearing, the pendulum & a few pages where he mentions the regulator and it's movement. I read these pages over and over dreaming about my own clock. This where I first encountered the mention of engaging & disengaging friction. He also diagrams why the 120 tooth wheels & 12 tooth pinions is the smallest combination to reduce or eliminate engaging friction.

So, the wheels in my prototype are all 120 teeth. Two of the pinions are 15 teeth and the pinion on the escape arbor is 16 teeth.

When discussing the regulator, de Carle mentions that they generally had 25 - 30 pound pendulums and driving weights of 2 - 4 pounds on a double line. This is why my pendulum weighs 30 pounds.

I was disappointed at first that it took 10 pounds to get my movement running and I attributed that to my gearing not being good enough.

Oh well, I thought, maybe it will still be good enough for a lot of the tests/ideas I wanted to play with anyhow. So once I was able to monitor the WWV time signals, I was thrilled that my clock was as accurate as it was.

What I feel I learned here was that even though my gearing wasn't up to the lowest possible friction standards, it was uniform enough that with enough driving weight the clock will keep very good time.

What I had read up to this point talked about low friction at the same time it talked about precision timekeeping. But what I found seemed to show that these two things don't necessarily go hand in hand.

When I started to design my next movement (pictured at the end of my first post) I purchased' "Gears for Small Mechanisms" by W.O. Davis, M.B. E. which is a pretty exhaustive study of gearing. I was pleased to find this statement:

"The longer term variations, arising from the teeth of the primary gears will produce detectable cyclic errors in timing. It is a good plan for this reason to ensure a smooth output at the first stage, by using a driven pinion having more teeth than one employs on the later stages. If any of the gears in the train run eccentrically there will be a further worsening of the output curve."

Although he is specifically talking about the value of a large pinion meshed with the great wheel, he is emphasizing the importance of a smooth transition of force from the great wheel to the train. By my mounting the great wheel as I have it ensures concentricity at this critical stage and perhaps has helped with the results I have found with my clock's rate.

Through the years I have come across some fine regulators that have some pretty large weights and have learned that I don't have anything to be ashamed of for what I have done with my first effort.

I wanted to go into all this detail to show how I didn't think I got the results I was shooting for, but instead picked up valuable lessons anyway. By offering as much background as I can it will be easier to show why I incorporated the changes I have in my next attempt at clock building.

 

[doc_fields]

Re: Owner built precision regulator - the beat goes on - pun intended!

The bearings I've mentioned are not stainless, but very good quality steel.....................doc

 

[jhe.1973]

Re: Owner built precision regulator - the beat goes on - pun intended!

Hi doc,

Thanks for the update.

I've been to the Sattler web site a few times. Always good for a drool!

 

[doc_fields]

Re: Owner built precision regulator - the beat goes on - pun intended!

That's the standard I hope to excel to soon. Their movements ARE cause for drooling if you appreciate well-finished, well-thought out movement design. I've ordered some of their material, poring over the pages that detail the movements and their construction, even tooth counts for the pinions and wheels........................doc

 

[jhe.1973]

Re: Owner built precision regulator - the beat goes on - pun intended!

Hi Everyone,

Sorry that it sometimes takes so long for me to get large enough blocks of time to get back here with updates.

Life seems to get in the way.

I’m going to start discussing the 2nd generation movement I am developing in spurts although I am hoping to be working on it steadily later this year.

Because of the lessons I learned from my prototype, and because I read that E. Howard made the entire back of his last astronomical wall clocks out of cast iron, I designed a new movement mount and case hanger machined from a 23.4 pound casting:



I said ‘case hanger’ because the 3 bosses on the rear are designed to go all the way through the cabinet back and protrude about 1/8 inch. The cabinet will be screwed to the cast iron mount from behind and allowed to float as the temperature & humidity fluctuates.

I have come to believe that for the utmost precision in timekeeping, wood is too unstable to be any part of the pendulum mounting system, but I don’t think that the entire back has to be iron either.

Wood has a natural warmth and beauty that I appreciate so I think that for a wall clock, this is my best solution.

The red arrows in the following views of the machined mount and movement point to the spring loaded plunger that contacts the winding arbor for the disengaging feature I mentioned earlier in this thread:



In this next view, the assembled movement is compared to the original design on the right. As I reduced the driving weight necessary through the years, I found I could shorten the distance between the plates by 3/8 inch just by using lighter line for the weight:



Note that the original plates on the right have a more or less conventional bridge for the verge.

When I was boring the clearance in the iron mount for the cap screws that held this bridge, the idea occurred to me to have the posts for the plates go all the way through the bridge and into the iron mount. This solves the problem of precisely locating the movement in relation to the pendulum suspension and also allows the entire train to be closer to the pendulum, especially the verge:



You probably already noticed that this movement does not stand on arms from below. I abandoned this time-honored way of mounting the movement to obtain as much stiffness as possible between the verge arbor and pendulum. However, with the original bridge design, the movement was still to be held away from the iron mount by a tiny amount. Now I feel that I have the maximum stiffness possible by clamping the entire movement to the iron close to the suspension point of the pendulum:



My next post will deal with the verge/crutch assembly and detail the reasons behind its unusual shape.

 

[DianneB]

My clock was within a few seconds per day right off the bat but the 110 volt clock varied as much as 20 or 30 seconds in a few hours.

New lesson for me, the electrical grid’s voltage varies a lot during the day although it averages out more or less it sure isn’t a regulator.

Just as an aside from this marvelous clock and as a techie for a power utility I have to address the above statement.

Power utilities in North America are all interconnected and operate at 60 Hz. Because of the interconnects, frequency is regulated very closely and variations of "20 to 30 seconds in a few hours" is simply not possible. If you are seeing that kind of variation in a clock on the main grid, suspect the clock. The power system has an over-all tolerence +/- 1 Second per day but because everybody is interconnected, the variation is far less than that.

Beautiful clock!

 

[jhe.1973]

Hi Dianne,

Thanks for your kind words about my clock and for clarifying how closely the frequency of the grid is maintained.

Something bothered me a bit as to using the frequency to explain the considerable variation I ran into.

Isn't the A.C. frequency the result of the moving electrical field inducing current in coils of the generator?

If so, then the speed of the generator has to change to alter the frequency, something that just doesn't make sense realistically/mechanically.

For a bit of trivia, here is A.C. clock I used. Still using it in my shop, just not for precision timing. One of these days I should check it again against the WWV time signal just for the heck of it.

 

[kdf]

It will be great clock, I like it very much!

Btw., to maintain constant frequency, speed of generators must be kept constant. However, load in network is not constant, so it affects on speed of generators. Generators are powered by different sources of mechanical power (steam turbines, water turbines etc.) and constant speed is kept by regulating these power sources. Some power sources are easier to regulate than others. Voltage output of generator is dependant on speed and load. At consumer side, voltage is dependant on load (Ohm law), so in spite generators speed is constant, voltage may vary at consumers side.


Electric clocks are not always with synchronous motors. Some of them have asynchronous motor, for example those which can start automaticaly. If train makes some load (there are some bindings for example), speed of motor can be lower than normal and clock will slow down. On the other hand, synchronuos motor will stop if synchronism with current is lost, so it can't be slower than normal. Voltage may affects on speed of asynchronous motor, but not on synchronous - it is always nominal and can be changed only with frequency.

 

[DianneB]

Not quite kdf. A synchronous motor can "slip poles" and run slow but could never run fast. Almost all plug-in-the-wall electric clocks are synchronous and will stay within the 1/2 cycle a day (1/120th of a Second) of the power system and they are not very sensitive to voltage - they simply follow the power system's sine wave.

When a generator in the power system is connected to the grid, is MUST run at the same speed as the grid. If it tries to run faster than the grid, it will simply deliver much more power than it is supposed to, in effect trying to "push the grid" but the grid is MASSIVE and no one generator (or even group of generators!) is powerful enough to change the grid frequency by itself. The power utilities know that the vast majority of timekeeping devices rely on the 60 Hz sine wave as their time base and keep within that 1/2 cycle on a continuous basis

 

[jhe.1973]

Hi Everyone,

In my post #33 I mentioned that I have the verge close to the suspension point of the pendulum.

I was thinking that the shorter the arbor from the verge to the crutch, the less possibility of twist in the arbor w/each impulse.

But that thought led me to consider the typical crutch configuration w/a pin, or yoke, at the end of a slender arm.

It seems to me that the typical crutch designs are susceptible to flexing as a spring in torsion.

Kicking all this around I came up with this design, still to be finished:



The crutch incorporates the beat adjustment with the two locking screws in the top:



These screws also lock the entire assembly to the arbor when tightened so the arbor can be a slip fit in the crutch & verge. There is no need for any other fastening.

Most important, at least to me, is that the verger arbor transmits no torque from the verge to the crutch. It only acts as the fulcrum for the impulse.

Next in importance is that the crutch is not a slender arm that can twist.

With the bulk that this design requires, I chose aluminum because it is approximately 325% lighter than brass and 300% lighter than steel. As it is right now the entire assembly weighs 39 grams or 1.3 ounces. I still plan to remove more weight however.

The verge is made in two halves that clamp the pallets. The assembly fits snugly in the slot of the crutch. The mating seam is visible in the hole in this photo:



The pallets will later be ruby. For now, they are ground from a scrap ball bearing race (I don’t throw anything away).



Another unique feature of the crutch is the addition of two-.050 inch HSS drill blanks to assure a point contact of the crutch to the centerline of the pendulum shaft:



In the last view the angled window for the crutch is visible. Here the bridge is removed to show the clearance cut in the rear plate and bridge:



For the last 1-½ years I have been aggressively been adding the machines & tooling I need to streamline my finishing of these clocks/movements. I hope to be working on them steadily by the end of this year.

Until I am at that stage, I don’t have more to offer, but I will keep checking this thread to see if any questions or comments come in.

P.S. I would like to REALLY thank all of you that have been watching this thread 'cuz it makes the time it takes to photo/edit/post replies worthwhile.

So, my thanks to each of you for your interest!

 

[harold bain]

Quite interesting, Jim. Always like to see someone working on "the better mousetrap".
One thing I don't see is how the pendulum connects to the crutch.

 

[jhe.1973]

Hi Harold,

Always great to 'see' you in any forum.

The crutch straddles the round pendulum shaft quite high up. Because it meets at an angle & not 90 degrees, I used the drill blanks to assure it would meet the shaft on the centerline. Here is a scan from the blueprint when I was playing with the idea. Its a cross section, but I am too lazy to put in the standard cross hatch marks:



I went with the 13 degree angle so I could take less off the plate and slightly notch the bridge.

I just noticed that I had the centerline of contact on the print. The 15 degree angle would be 3.045 in. & the 13 degree angle is 3.093 in., making it slightly longer.

 

[jhe.1973]

I hope to be working on them steadily by the end of this year.

Until I am at that stage, I don’t have more to offer, but I will keep checking this thread to see if any questions or comments come in.

Hi Everyone,

I realized that I should clarify that my, "I don't have more to offer" above is about this second generation movement that I was last discussing.

Just yesterday morning, the prototype clock had stopped at 1:38 AM. Turned out that the weight cord left the top pulley and jammed in the yoke.

Don't know why just yet, but suspect that the ball socket swivel for the top pulley might be sticky. I intend to play around w/other anchor points anyway so that might happen soon.

I also will be installing ball bearings on the great wheel arbor in the near future, so there is plenty to come.

 

[harold bain]

Jim, great design. Always good to see someone who doesn't just follow the trail, but makes his own path.

 

[jhe.1973]

Thanks for your compliment Harold.

One of the things I hope to accomplish here is to show that ideas almost always have to be developed, meaning tweaked, as errors are discovered.

Having been involved mostly w/one offs and custom stuff throughout my career, I have noticed that many people seem to be afraid of mistakes as if they have to be feared. Often we become our own worst enemy by being afraid to take a plunge.

This is why I try to make a point of showing how one step, even if it is a goof, has often brought out another way of doing something.

I have learned that, at least for me, once I get off the stick and take the first step, the next idea(s) come more quickly.

One of my favorite quotes is from a book written by the guy that took over Avis rental cars & turned it around:

"Babies learn to walk by falling down. If you beat a baby every time it falls down, it won't care much for walking."

 

[jhe.1973]

I intend to play around w/other anchor points anyway so that might happen soon.

Hi Everyone,

Robbed some time away from other things last night, so, as I threatened above, here is what I came up with for different anchor points. The former system is on the left:



I have wanted to try this latest position for awhile and having the cord come off the pulley was a good excuse to do it now.
As you can see, the weight is now farther away from the pendulum, closer to the left side. It is also closer to the front/door so it should be a bit better when it is down at the level of the bob.

Originally I had the pulleys in the same plane, so the top of the case was the stop for the weight pulley. I needed the entire case for the 10-pound weight I started with. Through the years I have reduced the friction in the movement and have shortened the weight so I have more flexibility inside the case.

This is as high as I can wind the weight now, but I think it will still run for 8 days. I am too lazy to measure it ‘cuz I wind it once a week anyway.



By having the upper pulley farther from the drum, the angular variation in the cord will be less as it winds down throughout the week. This will mean less change in the end thrust on the great wheel arbor.

I recall seeing a French regulator that had a second grooved drum (like the winding drum) instead of a pulley at the top of the case. That setup eliminates the end thrust on the great wheel arbor, as the cord will always be perpendicular to the arbor. I like that idea so I might try that someday.

You may have noticed that the angle of the upper pulley’s yoke is greater than before. I had to do a little re-work of the ball socket I had made to allow for the change.

What I had done originally was to turn a radius on the bottom of a 10-23 socket head cap screw and just have it seat in a socket cut with a ball endmill. Now I had to chamfer the top of the screw so it would stay buried in the socket that I also had to elongate.

That’s what these photos show:




Seems to be working just fine.

 

[jhe.1973]

Re: Owner built precision regulator - the beat goes on - pun intended!

Through the years I have come across some fine regulators that have some pretty large weights and have learned that I don't have anything to be ashamed of for what I have done with my first effort.

Hi Everyone,

Last week I was at the NAWCC National and saw this clock:



It's over 6 feet tall and is an example of what I said back in post #29.

The weight is larger in both diameter and length than the mercury jar as you can see here:



This really caught my eye and I took some approximate measurements right through the glass.

The weight is about 2" dia. X 10 " long and the mercury jar is about 1.70" dia. X 7 inches tall. The mercury stain is about 5.75" tall.

This works out to roughly a 12.9 pound weight to drive a pendulum with about 8.3 pounds of mercury.

Plus, the movement requires a hole in the case to get enough fall for the weight.

E. Howard used this trick in some of his big fancy regulators that had a tiny driving weight.

With a tall enough case, and enough room, you can make up for the lack of mass in the weight and impress people who only consider the size of the weight, not realizing that the distance traveled is a very important part of the equation.

I'm not trying to knock this clock because I find it very attractive and I know nothing about the quality of the movement.

It is just a great example of the statement that I made last February.

 

[jhe.1973]

Re: Owner built precision regulator - the beat goes on - pun intended!

Hi Everyone,

As some of you know, I'm using this clock as one of two for testing Nano oil and I am reporting the results in the clock repair thread here:

https://mb.nawcc.org/showthread.php?94121-Nano-oil-test-results-update

I recently made a camera mount from odds & ends gathered over the years:



This is so I can easily & quickly mount the camera in the same place & use the flash instead of setting up external lighting. With the flash, the light will always be in the same place so the shadows should be the same. Plus, I can now change the camera back to my tripod in a flash (pun intended).

While playing around with this setup & getting it to this stage, I noticed something that I hadn't found before.

I previously mentioned that the pendulum swing will vary slightly during the day, but I never was watching it closely enough because I was more concerned with comparing the second hand to the WWV signals. I only knew that it was a cyclic error.

What surprised me was that during the times of the day that it will gain swing, it does so within about a 20 minute window from maximum & back to normal. This shot is at the maximum. The minimum/normal swing is one line less.



Considering the 30 pound weight of the pendulum, this strikes me as a rather fast acceleration and deceleration. I still have to find just how many cycles like this it has during a 24 hour period. I think, only about 4 to 6.

For now, I'm only mentioning this because I just found it out myself but my curiosity is WAY up to go looking for the cause.

Now to find the time to dive into it!

Please don't anyone tell me that I just have to look at the dial to find the time!

 

[tok-tokkie]

Re: Owner built precision regulator - the beat goes on - pun intended!

I am surprised by the variation in swing of your clock as the gearing and arbors etc are all of such excellent execution. You estimate the period to be about 20 minutes. With a 1 second pendulum & 120:16 gear ratio of the third wheel to escape pinion so wheel 3 rotates in 7.5 minutes and wheel 2 in 60 minutes so they don't seem to be the culprits.

The Trinity Clock website shows how they measure disturbaces to their pendulum. They use an infra red beam to measure the swing time and derive the amplitude from that data.
http://www.trin.cam.ac.uk/clock/ >Instrumentation>Instrumentation & Data Processing for how they measure and >1 Day Summary shows the graphs. Measuring amplitude indirectly like they do interests me. How else could it be done without disturbing the pendulum?

 

[jhe.1973]

Re: Owner built precision regulator - the beat goes on - pun intended!

Hi Everyone,

I don't think that I ever totally explained the gearing problems that I encountered when I built this first clock.

My experience with gearing came from the power transmission end of gearing which is almost always step down gearing.

When I was learning clock repair the craftsman I was seeing knew a retired gear cutter that was doing gear hobbing as a hobby. (there's got to be a joke there but I can't find it)

Anyhow, when he had this person cut wheels or barrels, the teeth had the standard curved surface of an involute tooth. Teeth like these appeared stronger to me because they had a wider root than tip. BUT they are designed to mesh with same style tooth on both gears. This curve on each tooth allows the teeth to slide together smoothly.

Because step up gearing has different requirements (usually the lowest possible friction & most consistent transfer of motion) the wheel & pinion don't have the same shape tooth.

I made my first cutter for the wheels and when they were finished I cut my pinions with the same width teeth because I was used to shooting for minimum backlash. I still needed to learn that backlash is not a consideration on horology because the load is always in the same direction.

So, now I had a problem trying to get the wheels & pinions to mesh w/o binding. This was made worse because of the slight curve to the wheel teeth I mentioned earlier in this thread.

As I learned more about horological gearing I realized that to make this movement right I would have to make new arbors & pinions w/thinner teeth. Then I would have to re-locate the great wheel and the arbor that drives the escape wheel pinion. I decided to give what I had a a shot and see how it would work out.

Because the wheels are not meshing as deeply as they should, the last time I had the movement apart, I noticed a small shine where the radial flank of the pinion teeth meets the top radius. This shine/wear is more of a point rather than the wheel tooth 'rolling' across the tooth flank.

My guess at this point is that small variations in this point contact are changing the leverage applied, translating to the increase in power I am seeing at different time during the day.

So tok-tokkie, thanks for your comment about the excellent execution of the gearing.

My execution though is not the problem. My mixing two different gearing styles (tooth shape requirements) is where the problems lie.

Had I done more investigative work before starting I would have done better. But I am something of a risk taker and I know that I can tie myself in knots trying to study every detail and never get to the actual doing stage.

Actually, what has surprised me the most was that even though I knew that I had gear tooth problems I still achieved rather good performance in timekeeping.

By the end of this month I hope to be taking this movement apart to fit ball bearings to the great wheel arbor because my Nano oil test will have had a full year run. I will photo the pinion(s) at that time to fill ya'll in on the shine/wear I am talking about.

 

[Jim DuBois]

Re: Owner built precision regulator - the beat goes on - pun intended!

jhe.1973,
Firstly let me congratulate you on the execution of your work. Nicely done. Also, it seems you have arrived at a basic truth regarding clock movements, that being specifically that involute gearing is not the best solution for reasonably conventional clock mechanisms. There is at least one lengthy monogram that disagrees with this premise, but literally dozens that clearly state involute gearing is not recommended. (for the document that recommends involute clock gearing see 2004 “Cycloidal Gearing is Obsolete-A personal View” by Richard Thoen)

I am commenting on this thread not to disparage your work, or that of others. Your work is commendable, but unfortunately IMO the earlier effort is based on a flawed concept. My comments are intended only to bookmark your findings as another proof point regarding substantial issues when involute gearing is attempted in conventional style timekeeping mechanisms.

I am not a professional engineer, CMC, or for that matter any more than an interested party. However, that said, I have cut many hundreds of clock gears, or wheels and pinions if you prefer. I have serviced a number of precision clocks. I have made a number of movements of my own over a fair number of years. Some were more successful than others. None were precision regulators. I have also seen and been asked to “make well” perhaps 8 or 10 timekeeping mechanisms with involute gearing over the years, some quite similar to yours. So, my observations might have some value.

What has been found in virtually all these involute gear train rescues includes the following;

• Gear train is built to eliminate backlash, a feature you (and most others) have found to be troublesome and power consuming
• Gear train usually lacks sufficient end shake. That is to suggest that engineering rules for involute gearing have been followed, this concept works well for a transmission in one’s car, not so well in a timepiece
• All I have had in shop have required much more power than a comparable cycloidal gear trains, even when ample end shake and a more free fitting from wheel to pinions. This suggests more rolling or more sliding friction exists in involute gearing than in cycloidal gear trains, a premise stated in many places.

To the paper recommending involute gearing Mr. Thoen has a lot of opinions based on his own work, some of which is certainly valid, some, not so much. Some fair amount of his love of involute is based on his need to mass produce gear trains using hob generated profiles. Involute gearing is readily cut by hobbing, cycloidal is not. The cost and time to produce involute trains is substantially less in production environments, that environment is pretty much precluded in our prime area of interest.

There is at least one other attribute of involute gearing that is counter productive in clocks.Specifically, cycloidal gearing is to some degree “self cleaning” meaning that dust and other particulate matter may drop to the root of a gear tooth, where in involute has much tighter clearances and does tend to stop when it becomes a bit “dirty”. Now, we do prefer or mechanisms to remain “dust free” we also may well understand that is not common outside a lab.


The collective works of precision timekeeping from the likes of E. Howard, Seth Thomas, Waltham, Shortt, and a multitude of others suggest that cycloidal profiles can and do offer very efficient and precision timekeeping when well executed. Back in the day E. Howard built a precision regulator that keeps in motion a 30 pound plus pendulum with a sub 6 oz. weight, running on an 8 day train.

Today, a local collector has several precision E. Howard precision regulators, of 30, 60, 90 day durations, and one of 365 day duration. The driving weight on that year clock is 7.3 pounds and the pendulum is mercury filled and about 30 pounds (I didn’t weigh it, but it is pretty much a normal E Howard precision regulator pendulum, hence the 30 pound guess on my part) The owner keeps a WWV controlled electronic timer in the room with his running regulators…his results are truly remarkable for 100 year old plus devices kept in an environment that is subjected to walking vibrations, external traffic, barometric changes, minor temperature changes, normal winding disturbances, and show and tell visits.

In closing I recommend review of Derek Roberts series of 3 books “Precision Pendulum Clocks” to keep from reinventing the wheel….while his books are short on engineering details they do show many many efforts from the last 200 years regarding the area of discussion in this thread.

 

[jhe.1973]

Re: Owner built precision regulator - the beat goes on - pun intended!

Hi Everyone,

Jim DuBois: Thank you for your kind words referencing my work on this clock. I appreciate your comments and don’t feel that you are disparaging it. I completely agree that my initial tooth shape concept was flawed.

I am aware of Richard Thoen’s article & have even saved it in case I wanted to look into it any deeper.

You mention, “This suggests more rolling or more sliding friction exists in involute gearing than in cycloidal gear trains…”

I would like to add something that is only a suspicion of mine at this point.

I have a strong hunch that another problem using involute teeth for low friction devices is that when both engaged teeth have curved faces, they are acting slightly as cams trying to drive the arbors apart & thus increase the loading on the pivots. If true, this would contribute another factor to greater friction.

I just ordered the ‘Precision Pendulum’ series that you suggested. I am curious to see how much ‘reinventing the wheel’ I am doing. Thanks for that recommendation.

I dug up the remains of my first pinion cutting that I showed back in post #5 with a rack cut from my wheel cutter. Here is a portion of that photo:



I realized that I made a mistake in that post when I said that I used the same cutter for the wheels & pinions. In a different box, I found the cutter I made for the pinions. It is a standard woodruff key cutter that I surface ground to the thickness I thought I should have for the tooth space. This is how I cut the pinions:



Because this pinion blank has gotten banged up through the years & my tool & cutter grinder was already setup, I ground the end to clean it up for this show & tell.

On the 16 tooth pinion, with the bottom of the cutter on the center of the blank, I first cut on one side of the blank & then cut the other side before indexing.



This easily gave me radial flanks & a centered tooth w/o having to grind a cutter with slightly tapered sides. The 15 tooth pinions required a step or two more. The teeth still needed to be radius cut on the tips.

More following………………………….