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jdrichard

Burnishing Pivots and What it Does

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Yes it does, but not enough to endanger the fitting of the pivot into the hole. Burnishing removes the faint marks left in the steel after turning/alteration due to wear or cutting a new pivot. It creates an extremely fine finish, like a mirror finish. It also helps in the rotation of the pivot, preventing it from binding in the hole. If you gauged before and after I don’t think it would change, providing the work has been carried out correctly.

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It does remove (and compress) material, but it could be just a micron or two to several hundredths or more. Burnishers as used on pivots always have a straight grain texture, this is in effect a micro file. When burnishing on a Jacot tool you are removing a small amount of material as well as work hardening it. It does increase the wear resistance of a pivot. When I make a balance staff I generally leave the pivots 0.01-0.02mm oversize and bring them down to final size in the Jacot tool.

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