Hi folks,

I have wanted to rebuild the bell section of my stencil alto trombone for a few years. Now that I am somewhat "caught up" on the repairs and modifications in my shop (thank you Coronavirus), I would like to move forward with this alto trombone project.

I did some measurements a couple of years ago when I had some King trombones in my shop for repairs and noted that I should replace the tuning slide crook with a King crook. The problem is that my notes failed to indicate if the crook is from a 2B or a 3B! I'm pretty sure that the 2B is the correct choice but I want to double check before I order the part. Can any of you 2B and/or 3B owners take out your calipers and measure the outside diameter of the two sides of the tuning slide for me? Please measure the widest section of the large side and the smallest part of the small side in the brass part, not the nickel ferrules around it. Thanks for your help! :D

3B is about .630/.770, but I don't have a 2B on hand. Crooks are usually a bit oval shaped, so those aren't precise numbers.

Found it. 2B is about .595/.745

I would assume 2B, since the 3B is quite large on the lower leg.

Thank you so much Brad! The Slokar imitation alto has measurements of .596 and .767. Now I'm thinking I wrote it in my notes as just "King" because is was a "to be determined" situation. Since I plan to move the bell back about 7/8" and create a mini-gooseneck, I might go with the 3B crook and use the original large inner and outer tuning slide tubes and ferrules. Whatever direction I go, I appreciate your help!

Post pics of the project as you go!