Dettloff Music and Repair

Yikes! The low F/C key and low Ab/Eb key sit on the same hinge rod, and this one is quite loose. The hinge tubes are too big for the rod, so the lateral play will cause inconsistent closure of the pad and some weird key action for the player. I fixed this by making an over sized rod from a piece of drill rod stock, and drilling out the keys and posts to fix exactly. Here’s the old hinge rod compared to the the new stock.

To make the threads on the end, I filed down the end to the specific diameter needed for the 1-56 die. 0.073″, right on target! Then some more shaping and it’s ready for threading.

Check out these threads! Beautiful. They’ll be trimmed and beveled before I’m done. Now, since the keys are fitting on but they’re too tight to spin freely, I used lapping compound to sand the inside of the hinge and the outside of the rod at the same time.

After all this, I put the keys back on and clarinet, and! It doesn’t thread on. Whoops, I didn’t double check the pitch of the threads. This is the fourth new hinge rod I’ve made for this clarinet and they’ve all been 1-56. It’s strange for different rods on the same instrument to have different pitches, so it was easy to assume this one would be the same. These threads are 1-72, so I started over with a new piece of drill rod and a new appreciation for minute details.