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Hi Tmac,
Much faster to use a block of hard wood in a vice and a pin chuck
As you have rightly stated, the prices for lathe accessories is just going up and up, I dont think it will be long before someone with enough engineering sense starts producing this stuff again. I seem to remember David was considering making lathe accessories.the easiest and cheapest way I can see it is to have Paul buy me a rollimat for my birthday
…..problem is I am getting so old I cant remember what day it originally was 🙄 , ….ssssooooo, lets just call it today , WilliamWilliam, darn it, I thought you were buying me one for my birthday!
David,
I would be very interested to see how it turns out. I have spent some time on designing a jacot drum for my Wolf Jahn 6mm but decided against making one as I am just so used to polishing pivots by hand in a block of lignum vitae with the arbor held in a pin vice. I would have killed for one at the start, it took me a while to learn how to file a badly worn pivot straight and then to get a satisfactory polished finish with the pivot file/burnisher. If I was as rich as William I would have just gone out and bought myself a machine or the proper lathe attachments
. As I go through repairing clocks I see some awful work that has been done to them previously, I think this could be on the rise again as people just cant afford the proper tools for the job and there isnt enough decent training opportunities in this country any longer to make sure work is done properly. Its ok reading books to get a general idea but having someone tell you how to do it or where you are going wrong is priceless.
Seeing the prices pivoting attachments make on e-bay these days is a good indicator of where to start, along with the jacot drum, the most useful items that almost always seem to be missing from a used watchmakers lathe.
Paul.@Arutha wrote:
Nice find!
as long as they are big enough to clamp in a vice, you can start your groove with a small rat tail file. When you file a pivot in one of these blocks you then need to give the groove a quick brush out with a wire brush as particles can spoil the finish when you then burnish it. If you want to make a bigger block you could inlay the lignum into the edge of a cheaper wood block as its only the edge you need.
Hope that makes sense?
Paul.Paul:
I was thinking of holding the pivot in a collet in the 8mm lathe or a Jacot lathe and using this wood as a burnisher. In your example, does the groove hold the pivot which you then file with a metal burnisher? If so, that ia a much simpler approach. Simpler is usually better (david has taught me that).
Thanks!
TomHi Tmac,
I polish all of my pivots by hand, in a pin vice using the lignum as a bed held in a vice, the pin chuck is twisted back and forth whilst moving the metal burnisher in the opposite direction. It does take a little practice but the beauty of this method is it is very quick, you don’t have to keep changing the collets in your lathe to accommodate the different arbor sizes or the tailstock runners for different pivot sizes. Just use a little clock oil as lubrication. I do however polish the winding arbors in my lathe with buff sticks I have made from flat aluminium bar and then varying grades of wet and dry stuck to the bars with double sided carpet tape( I put a different grade on each side, so I have 3 bars with 6 grades of paper). They last much longer than cheap buff sticks and it doesn’t take long to replace the paper when it becomes worn. As winding arbors turn so slowly it is not so important for them to be burnished like a pivot, a good polish on them helps to stop them wearing through the barrel holes.You said you were thinking about using the lignum as a burnisher? Although it is hard I still don’t think it would work as well as a steel burnisher, remember some of these pivots are almost glass hard and no matter how hard the wood, I don’t think it would touch the surface. Embedding the wood with some form of media is also not the best way to go when finishing pivots as if any of the media ends up embedded in the pivot it will accelerate the wear of the pivot hole.
Hope that helps?
Paul.@Arutha wrote:
Hi Tmac,
I polish all of my pivots by hand, in a pin vice using the lignum as a bed held in a vice, the pin chuck is twisted back and forth whilst moving the metal burnisher in the opposite direction. It does take a little practice but the beauty of this method is it is very quick, you don’t have to keep changing the collets in your lathe to accommodate the different arbor sizes or the tailstock runners for different pivot sizes. Just use a little clock oil as lubrication. I do however polish the winding arbors in my lathe with buff sticks I have made from flat aluminium bar and then varying grades of wet and dry stuck to the bars with double sided carpet tape( I put a different grade on each side, so I have 3 bars with 6 grades of paper). They last much longer than cheap buff sticks and it doesn’t take long to replace the paper when it becomes worn. As winding arbors turn so slowly it is not so important for them to be burnished like a pivot, a good polish on them helps to stop them wearing through the barrel holes.You said you were thinking about using the lignum as a burnisher? Although it is hard I still don’t think it would work as well as a steel burnisher, remember some of these pivots are almost glass hard and no matter how hard the wood, I don’t think it would touch the surface. Embedding the wood with some form of media is also not the best way to go when finishing pivots as if any of the media ends up embedded in the pivot it will accelerate the wear of the pivot hole.
Hope that helps?
Paul.Yes it does. And would I be correct in stating that the bed depth for the pivot should be a little less than the radius of the average watch pivot?
Thanks!
tmac
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