How do you work a pivot lathe?

Kingleo49

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Sep 12, 2018
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E6AEC893-5EE7-4002-A675-56FB29A63ABA.png C482BB6B-40F7-4584-85CE-7BF89EB97173.png How do you work this pivot lathe? And does this look like it is worth the $50 they’re asking for it? I believe I can see how you would chuck up the balance staff in it but I don’t understand how you would make any adjustments to where is the Graver is or how you would get the thing to turn. Can anyone help me? I will try to include a couple pictures
 

karlmansson

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Apr 20, 2013
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Not a pivot lathe but a Jacot tool. It’s not used with a graver but with a burnisher. The pivot is placed in one of the hardened beds in one of the runners and rotated with a flat burnisher moved against the rotation. If done correctly it produces a very hard, very smooth surface. If done ever so incorrectly it produces broken pivots.

It’s driven with a bow. The one in the picture also requires the addition of a threaded ferrule by the looks of it. The most modern and still in production of this type of tool is the Steiner jacot.

You’re not really supposed to ask about values in this forum, and not link to active auctions, but it’s hard to tell if it’s worth that money. Depends on what you already have and what you want to use it for. A case for it would be nice though.

Best regards
Karl
 

watchwldr940

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Nov 26, 2008
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Hello there
It appears that you are looking at a very incomplete Jacot tool. I would step back and search youtube, etc for examples of this tool and how to use it. Don't necessarily assume that the person doing the video is using proper technique, I am just suggesting this so you get an idea of what to look for.
There used to be a video on AWCI's website on their use.
There are many posts here covering these tools, and I believe Archie Perkins also gives a good explanation of their use in one of his books. I'll have to look at them to say which book and chapter.
The best advice I can give you is to educate yourself before buying any specialized tool such as this. You'll save yourself time, money, and aggravation in the long run. George
 

gmorse

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Jan 7, 2011
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Hi Kingleo,

and I believe Archie Perkins also gives a good explanation of their use in one of his books.
So does Daniels in "Watchmaking", but George's advice is very sound. The Jacot tool, and indeed all dead-centre lathes such as the turns, need to be properly understood and then practised with for some time to become proficient. The one you show is, as has been explained, not only incomplete but a smaller, less common variant requiring a split pulley to work.

This is a fully complete Jacot tool, with an integral pulley.

Jacot Tool.JPG

It's used like this for burnishing the pivot and then rounding up the tip. The burnisher is hard steel with a grained surface, used with oil.

Balance in Jacot (beds).JPG Balance in Jacot (rounding-up).JPG

If you want to acquire a tool for re-pivoting arbors rather than burnishing them, this is the sort of thing to look for. Like the Jacot and the turns, it's also classed as a dead-centre lathe and does require a bow to work it.

Cased Pivoting Tool.JPG

Regards,

Graham
 

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