Loose tenon problem

[Matt4576]

I just picked up an early King 2B at an estate sale this morning. When I tighten the nut to attach the slide, the bell and slide still rotate fairly easily. What can be done to fix this?

Also, the knurling on the nut is pretty smooth so it is hard to loosen the nut. Any thoughts on fixing this? I'm thinking of stretching some rubber over the nut to provide grip.

[Dennis]

As a temporary fix, you could wrap a layer (or two) of teflon thread tape around the tenon. The long term fix is to have a tech shorten the tenon slightly. (The problem is that the tenon is bottoming out in the receiver. If you shorten the tenon slightly (probably 0.5 mm or less) the tenon will be short enough to tighten into the receiver.

Once the tenon is the appropriate length, you may find that the locknut knurling is acceptable. (Incidentally, this is a reason to try the temporary fix, first.) If not, you could have the tech replace the locknut at the same time as the tenon is being shortened. Another solution to the knurling problem would be to use a fine triangular file to deepen the knurling. That would be pretty labor-intensive, though.

[Bassposeur1]

Perhaps while the locknut is off for the tenon repair, have it metal laser etched? I'm unsure how deep you would etch but something has to be better than nothing...

[Doug Elliott]

One of my horns has a slightly loose tenon. Believe it or not, just some ink from a Sharpie is enough thickness to get it to stick. I had to do that on a gig a while back as an emergency fix, and it's still holding.

[octavposaune]

FYI, since 2Bs are still made. It isn't too hard to have the male tenon part on the slide replaced.

If possible see if you can meet someone with a modern 2B slide to see the if it is tight on your vintage bell section. If it isn't, the female tenon (slide receiver) is worn out and the whole brace assembly ($$) will need to be replaced.

If it is the male part on the slide, this is a relatively quick to replace and the part isnt a whole lot of money.

Benn

[CharlieB]

This problem seems to come up a lot on this forum.
The lack of knurling on the nut should not be a problem. The nut only needs to be lightly finger tight. It is a safety
back-up, not the primary means of securing the two horn pieces together. The male and female tapers, jammed together, do the work. Due to wear, these pieces can max out their insertion travel before they are fully wedged.

An easy and economical way to fix this is to carefully wrap one layer of adhesive backed aluminum foil tape on the tenon. This stuff:
https://www.homedepot.com/p/Everbilt-1- ... 05#overlay

Unlike Teflon tape, which can be a maintenance nuisance, the aluminum tape lasts a long, long time.

[BaronVonBone]

Remember it's ultimately plumbing.

Heh.