Tekippe Precision Regulator

[Phil Burman]

I have been aware of the Simple Regulator by Bernard Tekippe for some time and have searched extensively on the internet but can find very little detail regarding the remarkable performance of this clock. I’ve found the two NAWCC articles by Bernard Tekippe, one thread on this board, a YouTube video and of course Bernard Tekippe web site. For such a remarkable performance I expected to find masses of third party discussion and possibly a couple of detailed peer reviews, but there’s nothing. What have I missed?

Phil

 

[Tom McIntyre]

Bernie has been working on the regulator for a very long time. I believe he started back when the group of Atlanta NAWCC members got together to build a set of Willard Lighthouse Clocks.

He gave a presentation on the theory at the Ward Francillon Time Symposium in Portland OR and there was surprisingly little discussion there.

My personal view is that the concept is brilliant. I am sure you have studied it enough to know that the idea is to use a very large arc of the pendulum to minimize or eliminate the secondary errors from environmental disturbances, barometric pressure, etc. and to correct the implicit circular error by manipulating what we always have called "escapement error."

My guess is that the idea just does not appeal to traditional clock makers. Here is the paper that Tom Van Baak presented in Greenwich on the general subject with special reference to Harrison and Burgess, but no mention of Tekippe. http://leapsecond.com/pend/clockb/2015-tvb-Greenwich-ClockB-ppt.pdf. Here is another article on Martin Burgess Clock B, Burgess Clock B, The World's Most Precise Pendulum Clock, Is Made To A 250-Year-Old Design By John Harrison, Longitude Prize Winner And Inventor Of The Marine Chronometer | Quill & Pad.

Maybe someone at a prestigious lab somewhere needs to do a formal study on Bernie's clocks. I have been tempted to buy one, but have not done so.

 

[tok-tokkie]

On the contrary. Tekippe uses a vary modest pendulum arc. Quote from http://docs.nawcc.org/Bulletins/2010/articles/2010/385/385_131.pdf

The arrangement that gave the best results uses a three-pound pendulum with an amplitude of one degree each side of center.

The sentences before that describe how he came to that arc:

The escapement for the Simple Regulator was designed to have an escapement error that speeds up the pendulum by the same amount as the circular error slows down the pendulum, when the amplitude is increased. In this way these changes in the escapement error and the circular error cancel each other, even as the amplitude varies.

 

[Phil Burman]

Thank you both for the feedback.

Phil

 

[jkgarner]

On the contrary. Tekippe uses a vary modest pendulum arc. Quote from http://docs.nawcc.org/Bulletins/2010/articles/2010/385/385_131.pdf

The sentences before that describe how he came to that arc:

The paper is brilliant and shows a disciplined approach to improvement. What was accomplished is nothing short of phenomenal, without the use of barometric pressure control, or temperature control, or a vacuum, Tekippe achieved with his regulator comparable accuracy to what the best time keepers of the early 20th century were able to do with the compensations... time controls suitable for laboratories! The discussion not only details exactly how the result was achieved, but proves beyond any doubt using the latest testing tools that it functions as designed and is highly accurate.

If the industry had not moved away from mechanical clocks due to the advent of quartz crystal technology, or the use of atomic vibration to measure time, we all would have heard about Tekippe's work and lauded him as a great thinker.

Anyone who relishes the mechanical clocks and wish to keep these marvels of engineering working, should take a moment to read the article and appreciate what he accomplished.

 

[Tom McIntyre]

I agree that Bernie's work is brilliant. However, Harrison accomplished the same results in the mid 18th century with similar analysis and approach. The common theme is to identify errors with counter effects and manipulate them to minimize the system error.

Clockmaker John Harrison vindicated 250 years after ‘absurd’ claims

Martin Burgess' paper at the Longitude Symposium in November 1993 describes in depth Harrison's approach to precision timekeeping and why his technology was lost for 200 years. It is published in The Quest for Longitude, which is the proceedings of the symposium. Martin also mentions the display clock he created for Gurney's Bank which is briefly discussed in the Clock & Watch Bulletin. http://docs.nawcc.org/Bulletins/1980/articles/1989/260/260_236.pdf

 

[Phil Burman]

without the use of barometric pressure control, or temperature control, or a vacuum.

His clock does include temperature compensation.

Phil

PS: Also Philip Woodwards work showed that the need for barometric compensation was partly a function of where you lived on the planet.

 

[greenm01]

Now that Mr. Tekippe has passed, has anyone attempted to independently replicate his pendulum design and document the results?

 

[Steve7750]

Now that Mr. Tekippe has passed, has anyone attempted to independently replicate his pendulum design and document the results?

Funny you should ask ..... A friend of mine drew my attention to Bernie's clock a month or so ago and we have been trying to find out more. For this to fade into horological obscurity seems beyond understanding. The obvious first place to start was his son Byron but we have had no success in reaching him. The NAWCC museum folks sent some pictures but seem a little reluctant to furnish more. I have studied the article and there is a wealth of information there, and from it I have (just last week) actually built the pendulum from scaling pictures therein. In his own words, Bernie presented the information "so it could be further developed" but for now I'd be happy to simply duplicate his achievement. As you can see it's missing the pallets of course, but one has to start somewhere, and I can match his Q value. I'm happy to share my findings and collaborate with others who have interest, although I'd be happier if I had Byron's blessing.

 

[greenm01]

Hi Steve,

Excellent news. Glad to know someone is actively building Tekippe's Simple Regulator clock.

I recently discovered Bernie Tekippe's work while researching regulator clocks to build as a first clock project. I haven't yet read the April 2010 issue of C&WB #385, but found a used copy on eBay and look forward to studying the details. The relatively simple and elegant design, along with the claimed accuracy, make it a prime candidate.

The September 2017 issue of Horological Science Newsletter (HSN 2017-4) has a very interesting article by Mr. Tekippe titled "A Question for David Harrison" in response to an article in HSN 2017-3 titled:

"An analysis of the improved timekeeping performance provided by John Harrison's pendulum clocks" by David Harrison (no relation).

This article describes the principles outlined in John Harrison's final work: "A description concerning such mechanism as will afford a nice, or True mensuration of time" written in 1775. This work served as the design basis for the Burgess Clock-B that currently holds the Guinness timekeeping record for most accurate pendulum clock operating in free air over 100 days.

Bernie gives a description of his clock in HSN 2017-4 and claims (under figure 2) that his Simple Regulator outperformed Clock-B over an 84 day period. To my knowledge David Harrison never responded in the HSN and Mr. Tekippe's claimed achievement has lived in horological obscurity to date.

This performance almost sounds too good to be true.......!? In any regard it deserves to be independently verified. Is there still a Tekippe clock situated at the NAWCC Atlanta HQ?

From what I've gleaned, Bernie extensively used Microset timer to finely tune his clock design. Hard to know if the performance is repeatable, but worthy of study none the less.

Here are several YouTube videos I managed to find featuring Bernie, including a NAWCC Atlanta chapter Zoom memorial filmed during covid:







Long story short, I'm interested in potentially building this clock.

--Mason

 

[John MacArthur]

Steve and Greenm - I for one will be following with interest. Be sure to take and post plenty of pictures, as well as descriptions of your processes.

Johnny

 

[Steve7750]

Hi Steve,

Excellent news. Glad to know someone is actively building Tekippe's Simple Regulator clock.

I recently discovered Bernie Tekippe's work while researching regulator clocks to build as a first clock project. I haven't yet read the April 2010 issue of C&WB #385, but found a used copy on eBay and look forward to studying the details. The relatively simple and elegant design, along with the claimed accuracy, make it a prime candidate.

The September 2017 issue of Horological Science Newsletter (HSN 2017-4) has a very interesting article by Mr. Tekippe titled "A Question for David Harrison" in response to an article in HSN 2017-3 titled:

"An analysis of the improved timekeeping performance provided by John Harrison's pendulum clocks" by David Harrison (no relation).

This article describes the principles outlined in John Harrison's final work: "A description concerning such mechanism as will afford a nice, or True mensuration of time" written in 1775. This work served as the design basis for the Burgess Clock-B that currently holds the Guinness timekeeping record for most accurate pendulum clock operating in free air over 100 days.

Bernie gives a description of his clock in HSN 2017-4 and claims (under figure 2) that his Simple Regulator outperformed Clock-B over an 84 day period. To my knowledge David Harrison never responded in the HSN and Mr. Tekippe's claimed achievement has lived in horological obscurity to date.

This performance almost sounds too good to be true.......!? In any regard it deserves to be independently verified. Is there still a Tekippe clock situated at the NAWCC Atlanta HQ?

From what I've gleaned, Bernie extensively used Microset timer to finely tune his clock design. Hard to know if the performance is repeatable, but worthy of study none the less.

Here are several YouTube videos I managed to find featuring Bernie, including a NAWCC Atlanta chapter Zoom memorial filmed during covid:







Long story short, I'm interested in potentially building this clock.

--Mason

Thanks Mason,
Yes, that's the goal here too. Glad to connect with someone who shares our interest. It's my first as well, I'm certainly no expert clockmaker but I'd say a passable machinist. I am visiting the Sherline factory tomorrow to see their CNC mill, which can be used to make the wheels. To me that seems the hardest part.
This will be an interesting journey. Looks like we have someone else interested too, the more the merrier !
Cheers,

 

[Steve7750]

Steve and Greenm - I for one will be following with interest. Be sure to take and post plenty of pictures, as well as descriptions of your processes.

Johnny

Hi John,
I'll be sure to post some more pictures, but I have a long drive tomorrow so I am shutting shop for now.
Cheers,

 

[John MacArthur]

No hurry - I completely get how time changes in the shop, as opposed to "the real world". I saw an early version of Bernie's clock, I think at the Atlanta National nearly 40 years ago, and was impressed then. I'm a dedicated student of the Graham escapement, of which his is a variation.

 

[greenm01]

I managed to read C&WB #385 last night:

Tekippe's method makes sense: my takeaway is that he cleverly employed escapement friction to cancel out the circular error, in combination with a simple and efficient gear and power train, along with a temperature compensated pendulum.

Unfortunately, his article is light on specific details on how he actually adjusts the escapement pallet friction. I suppose this method is not limited to the deadbeat escapement itself. More than one way to achieve the same results by tweaking the pendulum impulse?

HSN 17-4 does shed some additional light by "adjusting the incline on the pallets"

I'm assuming this is a manual process specific to each clock.

Ultimately, he leaves it to the reader to develop their own impulse compensation using his timing methodology.

Anything I have overlooked? Very much in the learning stage.

 

[greenm01]

For what it's worth, a search on Google led me to this NAWCC bulletin by Dr. George Feinstein titled "Impulsing the Pendulum: Escapement Error" which was published in 2006:

untitled (nawcc.org)

From section IX on page 6:

"We can theoretically eliminate the combined change in circular error plus the impulse error. To do this we would need an escapement with two attributes: (1) The impulse must be toward the position of equilibrium and (2) The relative impulse location must be adjustable."

This statement closely aligns with the design principles found in Tekippe's Simple Regulator. Feinstein's paper is not referenced in C&WB #385.

A happy coincidence?

 

[Steven Thornberry]

User burt has suggested that the following thread might be of interest to this topic.

Tekippe Precision Regulator | NAWCC Forums

 

[Steve7750]

Thanks for your further replies, John and Mason. My visit to Sherline was interesting and productive (My thanks to Karl Rohlin over there) and I placed my order for the mill. Four weeks delivery.

Re. the comment on adjustable pallet inclines, I had been thinking to make mine adjustable anyway as I knew there would be some fine tuning required. Keeping the faces flat and polished through each iteration would be challenging. By using round agate stones (off the shelf) we get the benefit of the materials properties and infinite adjustment. This stone is only 1.85mm diameter though, so ours needs to be larger to duplicate the length of Bernie's pallet face to get the same impulse Worst case I guess if we have to stay with steel, we still get the same adjustability.

Can you both message me directly so we can connect? While I fully intend to continue sharing our progress with the forum, there will be many back and forth discussions that will clog the system and consume admin's time unnecessarily.

 

[John MacArthur]

Steve - I don't think Bernie's pallets were Brocot type. There's nothing wrong with Brocot escapements, but they introduce a different cycle of impulse, and probably a different escapement error. That said, they can induce a tiny bit of recoil which is what Bernie was using to offset the error. Several knowledgeable horologists have believed that these might well surpass standard Graham escapements, and as such might approach Bernie's. However, unless they are tiny, they will have a larger impulse arc and thus a larger arc of escape than either Bernie or Graham. They are usually found on smaller clocks with larger pendulum arcs. I'm intrigued enough to CAD the geometry.
Johnny

 

[Steve7750]

Thanks John,
Agreed, Bernie's escapement was not the Brocot type (which I had not heard of until now), but to my laymen's eye the pallets circular form seemed to give us the preferred adjustability. This is why we need guys like you in the group who know more fundamentals

I watched some videos and see that the flat isn't actually the impulse face in these jewels, it just gives clearance to fall between the teeth of the escape wheel. Could the flat be employed in our application though if one could be found that was long enough? Said flat face would provide the impulse in the classic way, however the locking face is of course curved which might be an issue?

 

[Steve7750]

Thanks John,
Agreed, Bernie's escapement was not the Brocot type (which I had not heard of until now), but to my laymen's eye the pallets circular form seemed to give us the preferred adjustability. This is why we need guys like you in the group who know more fundamentals

I watched some videos and see that the flat isn't actually the impulse face in these jewels, it just gives clearance to fall between the teeth of the escape wheel. Could the flat be employed in our application though if one could be found that was long enough? Said flat face would provide the impulse in the classic way, however the locking face is of course curved which might be an issue?

Thanks John,
Agreed, Bernie's escapement was not the Brocot type (which I had not heard of until now), but to my laymen's eye the pallets circular form seemed to give us the preferred adjustability. This is why we need guys like you in the group who know more fundamentals

I watched some videos and see that the flat isn't actually the impulse face in these jewels, it just gives clearance to fall between the teeth of the escape wheel. Could the flat be employed in our application though if one could be found that was long enough? Said flat face would provide the impulse in the classic way, however the locking face is of course curved which might be an issue?

 

[Steve7750]

An update on our project. I got my Sherline Accupro CNC mill ok and made the escape wheel to try it out. I know Bernie used an off the shelf product, but the one I bought looked quite rough so figured making my own would be best. I am also going to make a trip to visit Burt (who contributed through this thread) this month and service his Regulator with him so we can get a ton of dimensional information. Burt is a truly helpful guy and a great example of how horology enthusiasts help each other along.

 

[Tom McIntyre]

I knew Bernie and attended his presentation at The NAWCC Annual Symposium in Portland where he presented it. At that event the BHI showed the multiple pendulum clocks they were building to eliminate suspension error.
They got more attention than Bernie but I thought his was more interesting.
Bernie made a number of his clocks for sale and I came close to buying one.
I saw the word friction above and want to point out that escapement error is not friction but more like recoil. The fundamental idea Bernie had was to use that error and circular error to compensate in a clock with a large arc to minimize the environmental effects.
It would be a worthwhile project to try to catalog Bernie’s clock sales and see how they are holding up. I regret not buying one.

 

[Steve7750]

I knew Bernie and attended his presentation at The NAWCC Annual Symposium in Portland where he presented it. At that event the BHI showed the multiple pendulum clocks they were building to eliminate suspension error.
They got more attention than Bernie but I thought his was more interesting.
Bernie made a number of his clocks for sale and I came close to buying one.
I saw the word friction above and want to point out that escapement error is not friction but more like recoil. The fundamental idea Bernie had was to use that error and circular error to compensate in a clock with a large arc to minimize the environmental effects.
It would be a worthwhile project to try to catalog Bernie’s clock sales and see how they are holding up. I regret not buying one.

Well, I made a trip this week from California to visit Burt and help him service his Tekippe #7. As well as getting a thorough look into every aspect of the design and take dimensions, I was treated to the very best of Pennsylvanian hospitality from him and his lovely bride. Based on the information already gleaned from Bernie's own article, and this fresh hands on experience, I am confident that I will build one. I include a picture of one of my own wheels after the cnc machining. Stay tuned, this will be a long but interesting journey.

 

[burt]

Well, I made a trip this week from California to visit Burt and help him service his Tekippe #7. As well as getting a thorough look into every aspect of the design and take dimensions, I was treated to the very best of Pennsylvanian hospitality from him and his lovely bride. Based on the information already gleaned from Bernie's own article, and this fresh hands on experience, I am confident that I will build one. I include a picture of one of my own wheels after the cnc machining. Stay tuned, this will be a long but interesting journey.

View attachment 763677 View attachment 763678 View attachment 763680

Well after only a two day period for settling in, following a complete disassembly, cleaning, lubrication and change out of the suspension spring, I thought I test the clock's accuracy on the "MicroSet" timer set at the maximum of 240 beats. Using only the "fine adjustment" on the pendulum, here are the maximum deviations after about a half dozen tests. (+/- 3 millionth of a second) I think quite remarkable and tribute to Bernie's invention of escapement and his clock. I believe everything Bernie wrote about the results he achieved, with his clock, were true and accurate.

I can't thank Steve enough for all his help in the complete service of the clock and feel confident of his success, with his project to duplicate Bernie's clock. I intend to follow along with the rest of you but will say I'm already smiling.

 

[burt]

Well after only a two day period for settling in, following a complete disassembly, cleaning, lubrication and change out of the suspension spring, I thought I test the clock's accuracy on the "MicroSet" timer set at the maximum of 240 beats. Using only the "fine adjustment" on the pendulum, here are the maximum deviations after about a half dozen tests. (+/- 3 millionth of a second) I think quite remarkable and tribute to Bernie's invention of escapement and his clock. I believe everything Bernie wrote about the results he achieved, with his clock, were true and accurate.

I can't thank Steve enough for all his help in the complete service of the clock and feel confident of his success, with his project to duplicate Bernie's clock. I intend to follow along with the rest of you but will say I'm already smiling.

View attachment 763717 View attachment 763718

Thought I'd test the clock again today. The clock has been keeping time to the second. I thought when someone questions a post, writing "claimed" I take no offense and I don't think Bernie would either. What is there to gain by reporting something not true on a forum like ours? Anyway 4 consecutive tests and a spread of 2 millionths of a second maximum error. (1 reading .999999 and 3 of 1.000001) I remember talking with Bernie one day, discussing the various escapement names associated with clocks and I asked "what do you call yours"? He answered with one word, Tekippe.

 

[Steve7750]

Thought I'd test the clock again today. The clock has been keeping time to the second. I thought when someone questions a post, writing "claimed" I take no offense and I don't think Bernie would either. What is there to gain by reporting something not true on a forum like ours? Anyway 4 consecutive tests and a spread of 2 millionths of a second maximum error. (1 reading .999999 and 3 of 1.000001) I remember talking with Bernie one day, discussing the various escapement names associated with clocks and I asked "what do you call yours"? He answered with one word, Tekippe.

View attachment 764531 View attachment 764532

Glad to see your Regulator is doing fine after our collective efforts, Burt. I've been drawing up some movement parts in SolidWorks in addition to the Pendulum I had already completed. Also refining the Gcode to cut more wheels with the CNC mill.

 

[Steve7750]

Glad to see your Regulator is doing fine after our collective efforts, Burt. I've been drawing up some movement parts in SolidWorks in addition to the Pendulum I had already completed. Also refining the Gcode to cut more wheels with the CNC mill.

Ok, I have one pallet done so getting closer to being able to run some basic tests. I know it's a far cry from the full clock, but we've got to start someplace.

 

[Steve7750]

Ok, I have one pallet done so getting closer to being able to run some basic tests. I know it's a far cry from the full clock, but we've got to start someplace.

View attachment 764902

And the second pallet. I have the test rig running now.

 

[Tom McIntyre]

The first time I read this, I overlooked the reference to the ClassicClocks website. I just visited it and noted that the Custom Clock was still nominally offered for sale. I suppose I should just contact them, but does anyone know if any of the originals are still available (presumably not yet assembled material).

Here is the picture of the Bulletin cover that featured the clock.

 

[Tom McIntyre]

I thought Bernie's great insight into the regulator problem was that one need not calculate a lot of stuff if you made a clock with both circular error (large arc) and adjustable impulse error, the two could be adjusted to make the sum of the errors zero.

I just ran across this article from Horological Science Chapter from 2005 that provides all the math anyone might want to understand the problem analytically rather than intuitively. https://theindex.nawcc.org/Articles/Feinstein-ImpulsingThePendulum.pdf

Oops! I see the above was referenced earlier in this discussion.

 

[Steve7750]

I thought Bernie's great insight into the regulator problem was that one need not calculate a lot of stuff if you made a clock with both circular error (large arc) and adjustable impulse error, the two could be adjusted to make the sum of the errors zero.

I just ran across this article from Horological Science Chapter from 2005 that provides all the math anyone might want to understand the problem analytically rather than intuitively. https://theindex.nawcc.org/Articles/Feinstein-ImpulsingThePendulum.pdf

Oops! I see the above was referenced earlier in this discussion.

Hi Tom,
Bernie's website was one of the first places we tried a few months ago and you're right it appears to be still functional. However there has been no response to emails or phone calls. Even those with his son Byron's direct number were not responded to.

 

[Steve7750]

Hi Tom,
Bernie's website was one of the first places we tried a few months ago and you're right it appears to be still functional. However there has been no response to emails or phone calls. Even those with his son Byron's direct number were not responded to.

Work on the drawings continues.

 

[burt]

While we are waiting to hear how Steve is doing with his project I wanted to post these results, of the Tekippe clock, from this morning. We were away for 9 days so I wanted to see what the MicroSet results would be, as the clock didn't seem to deviate in any manor, since the cleaning. All I can say is Bernie's design is remarkable. I don't think he reported any results, of timekeeping, that were not obtained. This post isn't about me but of his clock. I set the timer to 240 beats for 4 consecutive tests and here they are. Is there a better clock, that runs in air, than his?

 

[John MacArthur]

Burt, those are darn good results. Do you have the software that was an accessory for the MicroSet? A longer period of testing, such as 24 hr or 1 week period logging will show up any tiny cyclical variations, which can then be analyzed. I like all those 0s and 9s.
Johnny

 

[burt]

Burt, those are darn good results. Do you have the software that was an accessory for the MicroSet? A longer period of testing, such as 24 hr or 1 week period logging will show up any tiny cyclical variations, which can then be analyzed. I like all those 0s and 9s.
Johnny

Johnny,

Thank you and as I said "a tribute to Bernie's design and skill".

Bernie wanted me, to do just that but I never did, as the clock kept such good timing results, I was satisfied as is. He did though and shared his findings, honestly I believe. He was proud of his clock and said to me, he thought it ran better than that "other" clock, mentioned in this thread.

Full disclosure: does the clock sometimes run outside of these remarkable results, yes, but not that often or that much.

I'm a big fan of you and your work and say that without any reservation!

 

[Tom McIntyre]

If you keep long term rate information, does it show tidal variation? I do not recall if Bernie mentioned that.

 

[burt]

No two clocks can be built "exactly" alike. No two clocks can be cased, mounted or be kept in the relatively "same" environment. So I think it very difficult to compare results. I made a sturdy case, chose the location in my home, which would afford the clock the best opportunity for performance but it's just a room in my home.. Hardly, the environment where observatory clocks would be housed, years ago. No, vacuum tank, special isolated room with temperature control, no thousands of pounds of concrete for a base etc. Yet the Tekippe, hanging on an exterior wall in my home, continues to preform to remarkable levels of accuracy.

I am not a clock builder or even mechanic but I am a pretty good observer. I think though, when a clock is tested in a long term trial, are we testing the clock or testing the way a clock runs in a ever changing environment? Just about EVERYTHING effects a mechanical clock. ( I try even not to stare at mine too much ) Temperature, barometric pressure, gravity and vibration as well as a dozen other factors directly or indirectly affect timekeeping. We can compensate for most but not all of them. Vibration is one that most comes to mind. My house sits 45 feet from the street that is used by busses and trucks all day long.

So how did Bernie pull it off with a clock that has limited parts, no jeweled or ball bearings and only temperature compensation ? Just for the heck of it I tested the clock this morning for one revelation (240 beats) of the escape wheel. I felt there was no need to go further. Never did I think, when Bernie and I fist talked, I would own a clock that performed like this.

 

[Tom McIntyre]

I have forgotten a lot of the discussion of long term error on HSN161. What I do recall is that there was an averaged error value that allowed one to detect the tidal variation in gravity on a sufficiently accurate pendulum clock,

i.e. you would expect a change in rate if the value of the gravitational force fluctuates. The reason is that the center of mass for the earth shifts with the tidal effect.

I recall charts of this value shown in the HSN newsletters, but I do not have time right now to dig that back up, Here is a link to HSN HSN Entry but the contact information may or may not be accurate.

 

[Steve7750]

I have forgotten a lot of the discussion of long term error on HSN161. What I do recall is that there was an averaged error value that allowed one to detect the tidal variation in gravity on a sufficiently accurate pendulum clock,

i.e. you would expect a change in rate if the value of the gravitational force fluctuates. The reason is that the center of mass for the earth shifts with the tidal effect.

I recall charts of this value shown in the HSN newsletters, but I do not have time right now to dig that back up, Here is a link to HSN HSN Entry but the contact information may or may not be accurate.

I'm delighted to see that Burt's clock is still performing well.
I have been making progress with the CNC machining of the wheels. Some trial and error of course, my collection of broken bits is getting larger. I thought I was feeding the 0.025" cutter appropriately slow at 0.040"/min, but I have since slowed to 0.010"/minute which has worked much better. The great wheel pictured took about 100 hours to cut. 80 of them were the teeth and holes, the rest was the crossing out. The latter can be done with a much larger bit, in this case a hefty 2mm In the last photo, the one on the right is the half hour wheel

 

[John MacArthur]

Nice looking wheels Steve. To point out the obvious, if you can find an air spindle, running much higher rpm, you can feed that bit a lot faster. My engraving with .020" bit at ~60k rpm I feed at 2 ipm, and possibly could go higher. What rpm are you using? How did you determine the tooth form? They look like pretty good epicycloids; are they true form?

Keep up the good work, and keep us posted,
Johnny

 

[Steve7750]

Nice looking wheels Steve. To point out the obvious, if you can find an air spindle, running much higher rpm, you can feed that bit a lot faster. My engraving with .020" bit at ~60k rpm I feed at 2 ipm, and possibly could go higher. What rpm are you using? How did you determine the tooth form? They look like pretty good epicycloids; are they true form?

Keep up the good work, and keep us posted,
Johnny

Thanks Johnny.
I guess the dental drill style turbo spindle would certainly speed things up, but it would mean a hefty rework of the Sherline head. I'm running at 2100 rpm as 2500 was getting the motor quite toasty.
As for the form, I figure you mean the smoothness of the profile compared to theoretical perfection. Well as you can imagine, any x/y fed curve must be made up of straight lines however small they may be. I can choose more or less target points on the G Code, but currently each tooth is made up of 32 individual point to point moves (with the stepper motor resolution superimposed on them). I'll dig out the microscope tonight and see what they look like.

 

[Jim DuBois]

Does anybody know how Bernie cut his wheels and pinions? I have only ever cut a couple of club tooth escape wheels using a milling cutter to mill out the profile. I have cut a few thousand using Thornton/Burgeon multi tooth cutters and have more recently been using more fly cutters for special sizes and forms. A 4th axis rotary works oh so very well on my CNC and I can cut and cross out a wheel much like this one seen here in an hour or less.

By the way, your work on this Steve is more than a bit interesting. I commend you for your tenacity in making the wheels. Do they check out as truly round? I notice the Accu-Pro specifications says .002" over 12" so you might be a half thou out of round on a wheel. I think that would not matter, just checking it out.

How thick is the wheel blank and are you cutting it in one pass or multiple passes? What sort of cutter are you using and how long do they last? Carbide or steel?

 

[Steve7750]

Does anybody know how Bernie cut his wheels and pinions? I have only ever cut a couple of club tooth escape wheels using a milling cutter to mill out the profile. I have cut a few thousand using Thornton/Burgeon multi tooth cutters and have more recently been using more fly cutters for special sizes and forms. A 4th axis rotary works oh so very well on my CNC and I can cut and cross out a wheel much like this one seen here in an hour or less.

By the way, your work on this Steve is more than a bit interesting. I commend you for your tenacity in making the wheels. Do they check out as truly round? I notice the Accu-Pro specifications says .002" over 12" so you might be a half thou out of round on a wheel. I think that would not matter, just checking it out.

How thick is the wheel blank and are you cutting it in one pass or multiple passes? What sort of cutter are you using and how long do they last? Carbide or steel?

Thanks Jim,
I imagine Bernie, being an old school horologist, he would have cut his wheels in the classic fashion but that's of course speculation. Others may know definitively. I chose the CNC method myself as I had access to the Gearwheel Designer software, and from discussions with existing users was told it was a more accurate way to go as everything could be done in one setup. Time will tell if that's the case for our build. I'd hope that 0.001" runout wouldn't cause issues. I haven't measured anything yet as I'm still working on hubs.

The blanks I'm using so far are 1/16" thick. After a spate of broken bits, I did try multiple passes but ended up with a step that I can only attribute to workpiece creep. I went back to full depth (0.070") but throttled way back on feed. I'm using 2 flute carbide bits TiCN coated. (McMaster-Carr). I don't have a feel for the lifetime yet, but I just started running the second layer of the Great wheel so we'll see if it makes it through another 80 hour cruise.

Glad you're finding this interesting, there will be plenty more milestones ahead.

 

[John MacArthur]

Steve, you said:
"As for the form, I figure you mean the smoothness of the profile compared to theoretical perfection."

The microfacets aren't what I was talking about, at those numbers they won't matter. What I was asking about is: are the teeth acting surfaces sections of circular arcs, or are they true epicycloids? Again, at this scale it is only a minute difference. I imagine Gear Designer is true to form which for clocks is epicycloidal.

You're doing great - you may ignore my focus on minutiae.
Johnny

 

[Jim DuBois]

Steve,

thanks for the information. You are doing something I didn't believe possible. And it looks like it is going well, be it very slowly? I have broken more than a few mills myself over the years.

 

[Steve7750]

Steve,

thanks for the information. You are doing something I didn't believe possible. And it looks like it is going well, be it very slowly? I have broken more than a few mills myself over the years.

Thanks Jim,
Yes, you certainly need patience with this method. I'm running the cut in the picture below at my office, and this is a remote camera screenshot. It's almost half way around after 40 hours. The sad part comes when you log in and see the dust pile has stopped being formed ... RIP cutter! I just found out that Sherline offer a head pulley mod that lets you go to 10K rpm, so I will look into that.

 

[Jim DuBois]

One thought I have regarding the process you are using. I am under the understanding that it is always better to clear all the swarf away from the milling cutter immediately. The reason being leaving the chips in the path of the cutter results in the chips being small as they are being cut again and again, shortening cutter life. A second side effect is the surface of the cut will be rougher, at least on a microscopic level, than if the chips are cleared while cutting.

I use an entirely different approach from you. I cut this great wheel last week, it is about 3" in dia., .200" thick, and 90 teeth. I cut the teeth on the blank conventionally using a 4 axis CNC and a multitooth epicycloidal cutter. I then glued the wheel with teeth to a Masonite board and screwed it though the center using a screw into an aluminum plate. I then crossed it out, in this case using a steel 1/8" mill, in 4 passes of .050" each pass. You will notice no swarf in the photo. That is because of the micromister I use to supply ever so little lubrication and coolant at about 60 PSI. I used travel of about 6" per minute.

I am not certain any of what I do is useful for your approach, but I would consider blowing the swarf away from the cutter if I were doing the work.

I am not a machinist in the sense of the word but I have been cutting gears for about 50 years. Very sorry I never took a shop or typing class.... self-taught and I have proven many times my instructor was an idiot.

 

[Steve7750]

One thought I have regarding the process you are using. I am under the understanding that it is always better to clear all the swarf away from the milling cutter immediately. The reason being leaving the chips in the path of the cutter results in the chips being small as they are being cut again and again, shortening cutter life. A second side effect is the surface of the cut will be rougher, at least on a microscopic level, than if the chips are cleared while cutting.

I use an entirely different approach from you. I cut this great wheel last week, it is about 3" in dia., .200" thick, and 90 teeth. I cut the teeth on the blank conventionally using a 4 axis CNC and a multitooth epicycloidal cutter. I then glued the wheel with teeth to a Masonite board and screwed it though the center using a screw into an aluminum plate. I then crossed it out, in this case using a steel 1/8" mill, in 4 passes of .050" each pass. You will notice no swarf in the photo. That is because of the micromister I use to supply ever so little lubrication and coolant at about 60 PSI. I used travel of about 6" per minute.

I am not certain any of what I do is useful for your approach, but I would consider blowing the swarf away from the cutter if I were doing the work.

I am not a machinist in the sense of the word but I have been cutting gears for about 50 years. Very sorry I never took a shop or typing class.... self-taught and I have proven many times my instructor was an idiot.

View attachment 768971

Looks good, Jim. What adhesive do you use? I'd thought about blowing away the swarf, but then it has to go somewhere. The particles are very fine, so many would end up airborne. I guess if I use a gentle airstream and similarly gentle extraction I could encourage them into some means of containment. That said, of course if they haven't been recut several times they should be a bit larger so less likely to take flight permanently. Thanks for the tips, I'll see what I can come up with.

 

[Jim DuBois]

I use Gorilla Glue which is a bit thick. I use accelerator spray from the hobby shop if I need it to set up quickly. It can be difficult to separate the parts from the backing but soaking in a can of acetone will loosen it over a bit of time. I started using the glue even on aluminum backing as it does keep the blanks in place better than most other approaches, and I have tried a fair number of different approaches. Never fun when a blank slips just a bit, be it crossing out or cutting teeth. 359 & 1/2 teeth never seem to work as well as 360!

While not necessarily applicable to what you are doing or how you are doing it, I mentioned the Micro-Mister as what I use. I have tried flood, spray, and mist coolant and lubrication. All very messy, but tend to work well. Often galvanic action between steel/iron and aluminum on the mills and fixtures was unacceptable to me. Did I mention messy? And I don't like to take a machine down to large pieces every time I use it for cleaning. In any event, the Micro-Mister uses a vegetable-based oil, and you can see the reservoir on my Mister is about 1/2 full. It was full maybe 15 years ago and I have run the mister on every wheel and pinion cut and every wheel crossed out, except for wood of course. The wheels and pinions done up might be over 1000 or 1500. So, the Micro is well-named and it leaves enough lube as to need to be wiped off when done using a bit of cotton.

I offer this thread drift to others who are reading this and want to follow a more conventional approach.