TromboneChat

The bell section and slide on my 88H are not 100% gripping each other. I assemble the trombone and after a few minutes the bell section rotates and falls onto my left shoulder. I have to really jam the two sections together to stop this happening, which doesn't feel right. How can I make this better ?

After inserting the slide into the bell section, do you give it a final twist (probably nore more than a few degrees) before fastening the retaining screw to seat the slide tightly?

This is the only thing I know to do short of taking it to a brass tech to slightly expand the slide tenon.

Try thoroughly cleaning off any grease or oil from the slide tenon and where that seats in the bell section, and also the "nut". The problem is often just that some lubrication (valve oil or slide lube) has gotten in/on the joint. I wipe mine with isopropyl alcohol (90%) every once in a while, but any reasonably mild degreaser (e.g., the orange citrus stuff) should work well. You may be amazed at the difference.

The approach of firmly seating it with a twist is also very helpful, but if you've managed to inadvertently lubricate the joint, it won't help much.

Thanks for the advice. I'll clean it and give it a twist.

Also, check out this discussion. viewtopic.php?t=33978

I've an early '80s 88H which had this problem. I think what happened to mine is the slide-side of the joint became compressed so the bell-side would sit on the slide-side threads. No amount of tightening would fix this and it would actually make the problem worse. I had a tech widen the slide-side tube slightly. In engineering terms, they used cheese instead of a suitable metal for the compression joint.

KWL wrote: Tue Jul 22, 2025 10:58 am Also, check out this discussion. viewtopic.php?t=33978

Thanks