Bell section comes loose & falls over

[Ogmusicteacher]

My Holton TR 181 bell has the nasty habit of rolling to the left and opening the horn up to 180 degrees. This does not seem to be affected by how tightly I turn the connecting screw linkage. At the suggestion of a local pro, I greased the screws to make sure the linkage was traveling as far as possible, but this has not helped. I cleaned off all the grease from the screws and the inside and outside of the connecting areas, but this hasn't helped either. The top of the slide section is plated, so I wondered if removing this rather slick surface high help. The problem seems more pronounced when using a cup mute, but the bell seems to fall over pretty much whenever it wants to. I can make it stable if I jam the bell section into the slide section by twisting it back and forth, but I'm concerned that forcing things together may create worse problems. Any and all suggestions would be greatly appreciated - having the bell flop over in the middle of a solo section in our recent concert was not fun.

[BGuttman]

Sounds like a worn tenon problem. If you put a "shim" of paper on the tenon, can you get it to fit tight?

A tech can file down the tip of the slide tenon so it fits properly. Sometimes you also need ot adjust other parts of the joint, so it's not a DIY type of job.

I don't understand what your problem with screws and linkages is or how this relates to the bell flopping problem.

[timothy42b]

Agree. The screw doesn't hold it. The tenon is a friction fit, and the screw just keeps it from loosening. So if it won't fit right the screw isn't going to help.

Older trombones didn't have the screw at all, and they even did mute changes without it. But their tenon fit into the receiver right.

I think you need to have a repair tech diagnose it.

[cigmar]

Try wrapping the slide tenon with plumbers tape.

[imsevimse]

I had this problem with a horn. I fixed it with an O-ring under the screw on the female receiver. I gave the advice to a friend who had the same problem with a Wessex bass trombone but it did not work and he had to take it to a repair shop. It can be different reasons why it does not sit tight.

/Tom

[blast]

Holtons do that.... it's the chrome plate on the slide side. Keep the joint clean and dry and if it continues use 'wet and dry' abrasive paper rubbed up and down the slide tenon.

Chris

[Kingfan]

I think the OP when talking about the screw linkage he meant the threaded collar on the slide tenon and the thread on the bell receiver section. I will be watching this thread closely - my TR180 has the same problem sometimes and it is gradually getting worse.

[Bach5G]

Get a pro to fix it properly.

[CharlieB]

"I can make it stable if I jam the bell section into the slide section by twisting it back and forth, but I'm concerned that forcing things together may create worse problems."
********************************
DO that. That's the design intent. If that procedure tightens up the joint, there is nothing mechanically wrong. Pressing the tapers tightly together creates the friction that the joint relies on to stay immobile. The mating surfaces should be clean and dry (no lubricant). A good alcohol cleaning can assure that. The threaded collar is a safety back-up and should be only lightly finger tight.

[hyperbolica]

Older trombones didn't have the screw at all, and they even did mute changes without it.

Yeah, but they added the nut because the use of mutes and heavier bell sections required more friction than you could produce with just the slip fit. The nut just jambs the parts together on the tapered tenon, creating more friction. There are a lot of heroic stories about how the nut doesn't do anything, but very few heros willing to use horns without nuts. The nut increases the friction, and the friction holds the bell up.

Look at Rath horns. Different means of creating friction, same concept at work.

If cleaning the joint doesn't fix the problem, get it looked at.

[baileyman]

I strip of $20 bill wrapped around the tenon should hold it. If it takes a new strip every day, a twenty will last about a week. Save the pieces to take to a bank and exchange. Repeat.

[CharlieB]

$20 bill.
Tried that once.
Didn't work.
The dollar is shrinking so fast that it won't hold for even one performance.

[elmsandr]

Older trombones didn't have the screw at all, and they even did mute changes without it.

Yeah, but they added the nut because the use of mutes and heavier bell sections required more friction than you could produce with just the slip fit. The nut just jambs the parts together on the tapered tenon, creating more friction. There are a lot of heroic stories about how the nut doesn't do anything, but very few heros willing to use horns without nuts. The nut increases the friction, and the friction holds the bell up.

Look at Rath horns. Different means of creating friction, same concept at work.

If cleaning the joint doesn't fix the problem, get it looked at.

I’ve never been described as a hero before! Now I need to add a cape and mask to my concert dress.

I play Bach and Edwards slides on a Shires valve section. The nut doesnt clamp down, so I just tighten it a little so it doesn’t rattle. Works just as well as with the nut.

Of course, what makes it work is that all of the tapers are good and clean. I’d still advise having a good nut, we aren’t all cut out to be heros.

Cheers,
Andy

[brassmedic]

The nut doesn't hold the joint together. The tapered fit of the tenon does. The nut only provides extra security that the joint doesn't come apart while you're playing the horn. If you have ever seen a horn where the tenon is worn out to the point that it is bottoming out, you know that you can tighten that nut all day and it won't help at all.

[baileyman]

I would be interested to feel down the inside of the bell end of the taper (the mortise end) and feel if there is a ridge at the end of the taper. It is possible the tapered tenon on the slide is bottoming out on the ridge (if it exists). In that case a cure could be to file off some of the tenon.

Presumably the same situation could develop if the mortise slides up to and hits the stop for the nut, preventing it from sitting fully. If that's the deal, then only a tech can fix it. Unless one takes the same file and thins the stop back a bit.

[Ogmusicteacher]

Thank you all for this great information! I have cleaned both the inside of the joint on the bell side, and the chrome portion on the hand slide side, and so far, so good. I could not feel a ridge up inside the joint, so hopefully bottoming out isn't the problem. If I still have a problem, I'll try the plumber's tape idea, I am hesitant to merely wrap the joint in paper (yes, even $20 bills! ). If that fails, it's off to the repair shop. Again, thank you all very much!

[lowcatjb]

I strip of $20 bill wrapped around the tenon should hold it. If it takes a new strip every day, a twenty will last about a week. Save the pieces to take to a bank and exchange. Repeat.

Any trombonist that actually HAS a $20 bill must have a day gig! (rimshot)

[Sgroth01]

Brass medic nails this one. For me, at least. The lock screw on my Benge 165f always comes loose, drive me nuts as I can hear it and feel it. Still, the bell section seems to hold firm. It will continue to bug me, I'm sure.

[OneTon]

Static and dynamic friction are proportional to the applied normal force. Static friction is greater than dynamic friction. By locking in the location of the taper, the nut ensures the normal force is applied and the static friction is not overcome.

In as much as nuts on the original Olds design had no serrations, and any serrations that are otherwise present are light, it could be argued that the nut are intended to limit the applied force to that required to maintain static friction. See the post on the growing Olds collection for a picture of a smooth nut.

[Sgroth01]