Jacot ring

[arron]

Hello,

I bought a Jacot tool (yea!).  It came with this ring thing.  Does anyone know where it goes and what it does?  Many thanks.  Arron.

[jdrichard]

1 hour ago, arron said:

Hello,

I bought a Jacot tool (yea!).  It came with this ring thing.  Does anyone know where it goes and what it does?  Many thanks.  Arron.

Don’t think this is from the Jacot??

[arron]

What? . . .  Well if I keep buying watch repair tools I'll eventually buy the tool this was meant to fit.  Mystery over.  Thanks JD.

[nickelsilver]

That's a safety guard for Jacot tool. It helps especially when burnishing conical pivots with long conical portions; it can be set so that the burnisher makes minimal contact with the conical section. If too much pressure is applied to this area the risk of breakage goes up. It can be useful too for straight pivots where the difference in size between pivot and and the next diameter is very small (dial side of many center wheels comes to mind). It helps avoid accidentally riding up onto the next diameter.

 

Whether it fits a given tool or not is another issue. All of my Jacot tools are Steiner, and they use 8.8mm diameter runners. There were numerous makers though, and certainly different sizes. It doesn't have to be a perfect fit, but does need to stay in place without shifting.

Edited March 4, 2022 by nickelsilver

[oldhippy]

That's a new one on me. Mine never had that part there was no indentation in the box for such a thing. Mine was handed over to me from my master. 

[nickelsilver]

11 minutes ago, oldhippy said:

That's a new one on me. Mine never had that part there was no indentation in the box for such a thing. Mine was handed over to me from my master. 

I've never owned one, but seem to remember there was one at school, and it's in Daniels' book. I've owned probably 15 Jacots over the years, and none had one. So pretty rare.

[KarlvonKoln]

13 hours ago, arron said:

Hello,

I bought a Jacot tool (yea!).  It came with this ring thing.  Does anyone know where it goes and what it does?  Many thanks.  Arron.

Actually yes, I know that one. It is a pivot stop/rest.  It is intended to go on the end of the runner that has the grooved shelves (no need for it on the lantern end).  I don't use it often; only on much larger staffs.  It acts as a rest to keep the pinion from jumping off the groove when you're burnishing on the draw stroke and bowing away from you.  As Nickelsilver also pointed out, it reduces risk of breakage too.  I have not yet had to burnish conical pivots, but I could see using it for situations like that.
I prefer to rely on technique.  But the larger diameter staves (think 18s) are harder to keep in the grooves, I admit, so I have used it a few times.

Edited March 4, 2022 by KarlvonKoln

[arron]

I hope everyone is having a good weekend.  I appreciate the additional information you've provided.  I have two questions.  1) Did i put the ring on correctly? (see yellow arrow).  It seems like a person couldn't work on the pivot with the metal flag in the way; or maybe if the staff very long the flag could go further to the left opening up a space for doing the pivot work.  2) The jacot is a complete set but most wheel pivots in a couple of pocket watches i tried will not fit into the right-side spindle indicated by the red arrow.  The escapement pivots and balance wheel pivots did fit.  What does a guy do with the other pivots?  Can you buy those spindles with larger openings separately?  What is that part called?  Or do you guys just use a lathe for the larger pivots?  Thank you.

[praezis]

On 3/6/2022 at 6:54 AM, arron said:

The jacot is a complete set but most wheel pivots in a couple of pocket watches i tried will not fit into the right-side spindle indicated by the red arrow. 

Did you try to reverse the spindle? Most have two usable ends.

Frank

[arron]

Thanks for the reply Frank.  I did try both ends of that spindle.  To my magnified eye they seem almost the same size; neither of which is big enough for any wheels other than the balance and escapements I've tried.