Worn bow-screw mortise - frog moving sideways

December 27, 2018, 9:34 PM · I have a nice pernambuco bow of indeterminate age. The mortise in which the adjuster screw eye moves is worn on one side, allowing the frog to move slightly sideways. The bow looks like it has a twist in it, but the stick is actually pretty straight. It's been like that for a long time but I think it's getting worse, as the more the frog moves around, the more wood is carved from the mortice. I was thinking that a repair would probably involve filling the mortice with a glued-in piece of pernambuco and then recutting the mortise.

Has anyone had this done, and what are the possible traps/problems?

Replies (3)

December 27, 2018, 10:29 PM · If it's carving away at the edges, it's possible your bow has a twist to it that pulls the frog to one side.

It wouldn't be so difficult to repair as you described. I don't think there would be any problems there.

December 28, 2018, 11:45 AM · Make sure that the eyelet is tightened into the frog so that the frog sits tight on the stick. If the frog still wiggles around, the front screw hole needs to be bushed and drilled true. If the mortice is really in bad shape, it can also be bushed and remade, but shouldn't have too much effect on the frog moving around. The mortice doesn't guide the eyelet, its the screw holes that do. Post a picture if you can.
Edited: December 28, 2018, 1:59 PM · It's really the facets on the bow which guide the frog, presuming that there isn't too much slop or misalignment somewhere in the screw/eyelet/bore assembly.

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