Kohlert C, C#G# tone hole repair

[modernicus]

Hey guys, here's my conundrum- on the bottom of the pic is my  Kohlert Boehm C, the top is the LaVesta HP Bb Boehm clarinetpages group effort buy from years ago, which I believe is a Kohlert stencil.  The keywork is extremely similar.  Obviously the previous knuckleheaded owners plugged up the hole on the LaVesta because the key is missing (part of the broken key was in the case).  You can see it is non-countersunk, not unusual on old clarinets.  Now on the C, the problem is that the flat spring won't stay in the channel, and slips over and blocks the pad from sealing and chews up the tone hole.  Did somebody cut this countersink later, that's why the spring channel is so rounded and shallow there?  It's so close to the hole itself, I have a hard time imagining this was original. It's even closer than than the LaVesta non-countersunk hole. I'm almost tempted to fill in the countersink with black epoxy.  Or should I just try to rebuild the edge of the channel so the spring stays in place?  I've also considered trying to file the groove a little deeper, but I'm a little skeptical of that as well.

[modernicus]

Picture.

[windydankoff]

I would cut the groove deeper, and be sure the spring is refined well to prevent further wear on the side of the groove.

[modernicus]

I would cut the groove deeper, and be sure the spring is refined well to prevent further wear on the side of the groove.

I'll give that a try, then!  I needed some screws for the flat springs on this clarinet and I found a parts joint from the same era of Kohlert in Bb, so fingers crossed they're the same when it arrives.

[windydankoff]

If you wish to modify a surface of wood that is unstable, I suggest to stabilize it before cutting it. The ultimate method is to apply some THIN superglue (CA glue) and watch it soak in. Apply again until you see soak in only slowly, then you know it is approaching saturation. It will harden quickly (evidenced by the irritating smell, best to avoid). You have now created a fiber composite!

This works even if the wood is slightly oily. It does not effect the appearance of the wood, if it isn't overdone.

After that, the wood may be cut or filed and it won't fray or chip so easily. Additional CA or epoxy may be applied if you wish to add material. The stabilized material forms a foundation to hold anything you wish to add.

See:  Best way to fill in a bore crack  https://clarinetpages.info/smf/index.php/topic,1419.msg9842.html#msg9842

I also find "black rubberized CA glue" very helpful. I use it now on wood and hard rubber. I learned about it on our topic: Repairing holes in the clarinet bodies. It's good for filling small spaces (shrinks slightly) and it isn't brittle. https://clarinetpages.info/smf/index.php/topic,1884.msg13509.html#msg13509

[modernicus]

Definitely familiar with thin CA glue and have used it for crack repair, but not the black rubberized stuff in the other link- it'd be interesting to get some and test out what all it can do.  BTW, the tone hole itself has been cleaned up quite a bit from what it was. Some chips have been filled and the tone hole has been  sharpened up.  It was a lot more torn up from the spring.

[windydankoff]

The black rubberized Starbond doesn't get super-hard and brittle, like the usual CA options. It can be trimmed easily with a sharp blade. It shrinks, but not much. It applies with good control.  It seems to emit less of that awful vapor when hardening. It sticks to hard rubber like a weld! I now use it for many general purposes. I bought the larger bottle and wish I had just gotten the small one since it may not store for years.

[modernicus]

Well, the screw for the flat spring wasn't the same from the Kohlert Bb, but luck has it that I ordered some assorted clarinet screws from China, where they claimed the rod screws were 1.9mm, but in actuality were like 1.99mm.  The flat spring screws that came with them, though, seem to work on this Kohlert C.  Crazy world!