Antique frets and 12 string tailpiece

[Richard500]

Finishing up the restoration of an Oscar Schmidt 12 string bowl back. On this one, as on several others, the frets are not only narrow, but essentially flat-topped. Were they always crowned? Am I just looking at old leveling jobs?
Second item: the tailpiece. My other one has the scalloped stamped common 8 string design. This one, a modern 8 string. Was there an actual 12 made back then, are there any today? Not critical issue, just curious. Finished the (by my standards) tricky brazing of a sheared worm bracket without melting the aluminum button. Haven’t tested it under string tension yet. Will post photos if successful. It’s a rather odd problem and repair, but might be of interest.

[Jim Garber]

I highly doubt that OS bothered with actual 12 string tailpieces. You can sometimes find modern ones made in Germany but I would just go with what you have.

[Richard500]

Ok, all done. Three separate odd jobs: tuner braze, binding repro, and tailpiece.
The 12 string tuner had one broken worm bushing - not pulled out, but sheared. The bushing is brass, the plate steel and the button aluminum, so there’s no chance to remove the button; the bushing has to be repaired in place. To do this, the tuner plate is removed, the residual plating removed in that area, the worm shaft is heat-sunk by wrapped copper wire and the button with a clamp. Silver solder, using the OO torch tip (for the first time!). Holding fine so far.

The binding is segmented black/white pieces, approximately 1/4 round, and I could not find anything close, and didn’t want to hand cut lots of tiny bits or set up to mill them. I used a hobby thermoplastic - polycaprolactone, malleable at 150F. Cut a square rebate in the edge of a board as a mold, and filled it with the plastic. When it hardened, used a handplane to contour the quarter-round. Spray painted with a plastic-fusing rattle can in ‘butterscotch’ color, then made a stencil mask for alternate segments and sprayed them black. The strip was then removed from the board and CA glued to the mandolin. Flexible enough, and so far, paint adhesion is good.

The next problem is the tailpiece, so I made a 6 hook, and very sturdy plate from 304 SS, by off-hand grinding with a thin wheel, and cleaning up with a dremel, then spotwelded
it to a cut-down steel 8 string tail, so I could use two strings per hook.
The exercise was partly see if the new, distressed instrument would have the same surprising bass tonality as my other one. It does.