A design for a belt-driven Jacot Tool ...... ?

[Dell]

I only restore torsion clocks and I only burnish the pivots on my Pultra because the pivots don’t wear on torsion clocks using an home made Jacot drum held in the tailstock and I was always told to use speed to burnish is it different for watch pivots?

Dell

[Neverenoughwatches]

1 hour ago, Endeavor said:

Of course, I can not talk about "long time experience" (I've just started), but from what I've observed is that if you don't keep the file flat on the runners-bed, the pivot has room to "escape; it rolls itself "out of bed" ( ) This hasn't anything to do with how hard you press down, the pivot has no mass, friction or power enough to push the file upwards.

Because my tool is belt-driven, next to having my both hands free, I can fully concentrate on the file and the pivot, which coincidentally are the two most important parts in this exercise.  If needed, I can support the hand holding the file with the other hand, or, with the other hand hold (additionally) the tip of the file for better control of the files angle. Also, IMHO, one doesn't need huge strokes with the file. In reality and under the microscope, a 1 cm stroke is already huge compared to the size of the pivot.

Also, having belt-driven, I can position the microscope right above the Jacot tool and have a good view of "what's happening". I've experienced too that the pivot nearly rolled "out of bed" (due to the "incorrect" position of the file), but since I had only one thing to concentrate & to focus on, I could stop immediately to prevent worse. I guess my brain doesn't like multi-tasking, hence having the Jacot tool belt-driven is for me the solution.

Of course, if the bow driving works for other people, perfect !

Two personal remarks I like to make, or better; "food for thought";

1) It seems to me that when trying the bow, the hand holding the file mimics the movement of the hand holding the bow, but obviously in the opposite direction. My file strokes were way too long, causing the file to "wobble", tilting off the beds horizontal plane and thereby giving the pivot room to "escape". Nickelsilver's video showed how he controls the stoke-length and the position of the file, a method initially unknown to me. Since I now can fully concentrate on the file and the pivot (the rest is taken care of), that problem is solved.

2) When I was into old Land Rovers, I took an off-roading coarse in the Belgium Ardennes, conducted by a man who participated multiple times in the Paris-Dakar rally. He made a remark which always stayed with me: "When you go too fast, unwanted things start you to overcome".

Using nickelsilver's fixed file hand position part resting on the jacot will stabilise the file and regulate the stroke lengths. 

4 minutes ago, Dell said:

I only restore torsion clocks and I only burnish the pivots on my Pultra because the pivots don’t wear on torsion clocks using an home made Jacot drum held in the tailstock and I was always told to use speed to burnish is it different for watch pivots?

Dell

Nice tool making dell. I guess if speed can be used safely, at the end of the day the fragility of a watch pivot dictates how the process is carried out. 

[Razz]

Just a newbie question here. How do you reverse the direction on the motor driven pulley? Or do you lift the burnisher at the end of the stroke because you only burnish in one direction and reposition it then stroke again in the same direction and rotation of the pivot? With a bow you push and pull bidirectionally, with a motor it spins in one direction. If you lift and replace the burnisher the action could cause an introduction of error on the angle and other potential for things to go wrong, it seems to me.

[Dell]

12 minutes ago, Razz said:

Just a newbie question here. How do you reverse the direction on the motor driven pulley? Or do you lift the burnisher at the end of the stroke because you only burnish in one direction and reposition it then stroke again in the same direction and rotation of the pivot? With a bow you push and pull bidirectionally, with a motor it spins in one direction. If you lift and replace the burnisher the action could cause an introduction of error on the angle and other potential for things to go wrong, it seems to me.

Move the burnisher backwards and forwards keeping the same pressure on , just like you would with a file, if you lift then there is a chance of it coming out of the drum.

Thats how I do it anyway and it’s just my opinion.

Dell

[JohnR725]

4 hours ago, Razz said:

How do you reverse the direction on the motor driven pulley?

it brings up an interesting question of how does the next quote work.

On 2/18/2024 at 2:58 AM, Dell said:

I only restore torsion clocks and I only burnish the pivots on my Pultra because the pivots don’t wear on torsion clocks using an home made Jacot drum held in the tailstock and I was always told to use speed to burnish is it different for watch pivots?

to be honest I'm not sure what a Pultra is but the rest of it indicates he's burnishing pivots in a lathe. So in a lathe typically the motor spins in one direction so how does he reverse the direction? 

here's an example of a picture I found of burnishing in the watchmaker's lathe and that looks like the standard belt so how does the motor go backwards and forwards? 

 

[Razz]

2 hours ago, JohnR725 said:

it brings up an interesting question of how does the next quote work.

to be honest I'm not sure what a Pultra is but the rest of it indicates he's burnishing pivots in a lathe. So in a lathe typically the motor spins in one direction so how does he reverse the direction? 

here's an example of a picture I found of burnishing in the watchmaker's lathe and that looks like the standard belt so how does the motor go backwards and forwards? 

 

Part of my point. You are running the burnisher in 2 directions on the 1 directional spinning pivot in a lathe. I thought you wanted only to run the burnisher across the pivot in 1 direction, hence the back and forth with the bow changing direction of the pivot spin with the pull and push of the burnisher make the burnisher slide across the pivot in only 1 direction for a better polishing action as there is a "pile" of metal on each side of the scratch 'trench" so the reversing would push or pull both piles into the scratch while a unidirectional spin would push only one side of the pile into the trench and the other would have to spread out on top of the unscratched surface and would eventually have to be removed to end up with an even surface. Sorry about the run on sentence.

[Dell]

I only burnish in one direction because as I said I only restore torsion clocks, single direction may not be the correct way but I has always worked for me , for interest this is a Pultra lathe English made 10mm, 

Dell

[Neverenoughwatches]

1 hour ago, Razz said:

Part of my point. You are running the burnisher in 2 directions on the 1 directional spinning pivot in a lathe. I thought you wanted only to run the burnisher across the pivot in 1 direction, hence the back and forth with the bow changing direction of the pivot spin with the pull and push of the burnisher make the burnisher slide across the pivot in only 1 direction for a better polishing action as there is a "pile" of metal on each side of the scratch 'trench" so the reversing would push or pull both piles into the scratch while a unidirectional spin would push only one side of the pile into the trench and the other would have to spread out on top of the unscratched surface and would eventually have to be removed to end up with an even surface. Sorry about the run on sentence.

There was a thread ages ago regarding this one or two direction pivot polishing. I think we came to the conclusion that two way is better than one way. Something to do with levelling the peaks and troughs better, moving material and work hardening more evenly. Its not just fine filing and polishing, the surface is being compressed and case hardened. You could just buy one of these instead

 

 

[Razz]

9 minutes ago, Neverenoughwatches said:

There was a thread ages ago regarding this one or two direction pivot polishing. I think we came to the conclusion that two way is better than one way. Something to do with levelling the peaks and troughs better, moving material and work hardening more evenly. Its not just fine filing and polishing, the surface is being compressed and case hardened. You could just buy one of these instead

 

 

So on a mechanicl lathe it is 2 directions but on a jacot with a bow it is 1 direction? The pivot spins 1 way and the burnisher goes in 2 directions.

[Neverenoughwatches]

11 minutes ago, Razz said:

So on a mechanicl lathe it is 2 directions but on a jacot with a bow it is 1 direction? The pivot spins 1 way and the burnisher goes in 2 directions.

no I'm not with you. With a lathe the pivot is spinning in just one direction the burnisher is moving backwards and forwards. With a jacot and a bow the pivot is moving first in one direction when the bow is pushed forward and then reverses when the bow is pulled back. The burnisher is again moving backwards and forwards in the opposite direction to which the bow is moving.  The burnisher doesn't have teeth as such not directional teeth, so it burnishes in the same way moving forwards as it does moving backwards. 

[Razz]

1 hour ago, Neverenoughwatches said:

no I'm not with you. With a lathe the pivot is spinning in just one direction the burnisher is moving backwards and forwards. With a jacot and a bow the pivot is moving first in one direction when the bow is pushed forward and then reverses when the bow is pulled back. The burnisher is again moving backwards and forwards in the opposite direction to which the bow is moving.  The burnisher doesn't have teeth as such not directional teeth, so it burnishes in the same way moving forwards as it does moving backwards. 

I think I have it now then, the lathe would be polishing in 1 direction and the jacot in 2 because the pivot is reversing with the bow and only going in 1 direction with the lathe.

[Dell]

I am an elected member of the British watch & clockmakers guild and there is a nice article in the latest magazine about pivot burnishing using a lathe & a bit of equipment at right angle to the headstock designed by Jim Arnfield, the article is by J Malcolm wildFBHI.

[Neverenoughwatches]

56 minutes ago, Dell said:

I am an elected member of the British watch & clockmakers guild and there is a nice article in the latest magazine about pivot burnishing using a lathe & a bit of equipment at right angle to the headstock designed by Jim Arnfield, the article is by J Malcolm wildFBHI.

I guess you wouldn't be able to show it here. 

[Dell]

11 hours ago, Neverenoughwatches said:

I guess you wouldn't be able to show it here. 

Not sure about copyright but found the picture and a very good article here, fig 17.

https://bhi.co.uk/wp-content/uploads/2023/02/08-HJAugust22-AOTM.pdf

Dell

Edited February 21 by Dell
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