Hi, Larry
Your "double leather" is totally different than my way of doing it, which proves how accommodating the process really is, given leather and white or yellow glue.
I cut a strip of buckskin, and point the end. The width of the strip depends on how loose the screw is. I try the dry leather in the hole -- sometimes a pair of sharp tweezers helps -- and see how much sticks out. I take the strip out and clip this extra off, so that the strip just fills the hole. At that point, I have a variety of ways of wetting the leather, depending on the size of the hole. The process can be scaled up or down, depending on the size of the screw and what it has to do. It works, from big hunks of thick heavy shoe leather for lyre screws all the way down to tiny slips of buckskin leather 1/8" wide and 3/8" long, for the long hinge screws.
I use white glue, though any carpenter's glue (yellow glue) or Titebond will work. The thing is to get the leather wet so it is stretchy and can conform to the screw threads. The glue also mends the splintering wood so it won't keep turning to sawdust.
For the long-hinge screws, I take out the screws a few at a time, insert dry very thin short pointed strips of leather, and then put a very small bottle of Elmer's against the holes and squeeze, flooding them. Then I install the screws, and the extra white glue oozes out around them. I wipe this off.
For larger screws, I guess how wide a strip of leather I need, clip it to length after trying it in the hole, then I wet it well with the white glue, insert if, and put back in the screw. If the screw is almost firm enough in the hole but still can overturn with a little effort, I usually leave it, because once the white glue sets it will be all right. If I feel the hole is still too large, I take the screw out and add another strip on the other side of the hole.
I've had excellent results and near-perfect durability for this repair.
I say some things to customers. I explain that for toothpicks, shoepegs, and so on, the wood grain goes in the wrong direction, so the screw threads will chew them to sawdust. Then I talk to them about how stretchy leather is when wet, but how rock-hard it is when it dries. I describe how people made shields in the MIddle Ages by makes a wooden frame and stretching wet leather around it, which dried rock hard. I then talk to them about how the leather gets squeezed into the screw thread and then dries hard, rebuilding a perfectly fitting thread for the screw. I end up by telling them how white glue is still flexible when dry, and how it never, ever, seizes a metal part, so that the screws can be removed and screwed back in however many times one needs to.
Dandy repair. It's saved me a lot of grief over the years.
------------------------------
Susan Kline
Philomath, Oregon
Original Message:
Sent: 12-06-2015 12:33
From: Larry Messerly
Subject: Stripped case screw holes
I use leather almost the diameter of the hole and twice the depth. Put glue in hole, double leather, press to bottom with mute handle ( the pointy bit). Has never failed me either.
------------------------------
Larry Messerly, RPT
Bringing Harmony to Homes
www.lacrossepianotuning.com
ljmesserly@gmail.com
608-518-2441
928-899-7292