Question - Expanding a tuning slide

[gocsick]

What is the right method and tool to expand a slide that is a bit too loose?

[York-aholic]

A very, very well trusted repair shop?



Said only partially tongue in cheek.

[bloke]

The main tuning slide on my most expensive instrument is perfectly aligned, but not loose. It wasn't bad before I shortened the ferrules in order to slightly shorten the instrument, but I guess I couldn't help but dial it in to "zero", when I reassembled it. (Think of 1960s or 1970s built Schilke trumpet first and third slides.)

Slide expander tools work but they are crude. Rather than use one of those and do my best to screw up the inside slide tubes as little as possible, I decided instead to install a friction stop which prevents it from sliding, but which is located next to my right thumb - whereby I can press a lever, release the friction, and pull out the slide easily. I just couldn't stand the idea of intentionally messing up the alignment nor intentionally messing up the inside slide tubes.

If someone does use one of those expander tools - which is likely what you will choose to have happen, I would hope that they would do what I do when compelled to use one of them, pick only one of the two inside slide tubes, and render it very subtly barrel-shaped, so it's not made too large on the bow end nor on the tip end, and only grabs enough along the middle of the tube to add enough friction to not slip. If your slide actually is leaky - rather than perfectly aligned, you might choose to replace the pairs of tubes with new pairs that fit as they should.

Realize that I am an outlier regarding my views on this, and most people are quite eager to just use a slide expander on any instrument of any quality level. I have people who spend $10,000 - $20,000 on gold flute head joints that don't quite fit their flute bodies who are eager for me to jab slide expanders into the male fitting area of those crazy expensive head joints, rather than building up the exterior of the insertion area with something like gold or silver. Whatever. "It ain't mine" (and I do have an extra high quality slide expander - of that size range - that I use on those head joints, just fwiw).

[MiBrassFS]

They can be burnished to fit. They (“technicians…”) have to have the right stuff and the “right stuff.”

[bloke]

They can be burnished to fit. They have to have the right stuff and the “right stuff.”

I don't claim to be the world's greatest repair guy, but when I burnish tubes to make them larger, I prefer to have more tubing than the piece I'm working (so I've got something to hold onto). I suppose using that method I could solder another tube onto the end of the one being burnished. It also requires a good deal of skill to avoid ovaling - when burnishing. The burnishing method does result in a smoother surface.

If you read some of my recent blather, the larger 4th valve bore inner slide tubes on a Holton 345 I'm working on were fabricated oval, and I had to squeeze them (with these old man fingers) to verify the correct diameter in order to duplicate one of them.

[MiBrassFS]

I understand old man hands… and elbows… and shoulders.. etc!

[gocsick]

If someone does use one of those expander tools - which is likely what you will choose to have happen, I would hope that they would do what I do when compelled to use one of them, pick only one of the two inside slide tubes, and render it very subtly barrel-shaped, so it's not made too large on the bow end nor on the tip end, and only grabs enough along the middle of the tube to add enough friction to not slip. If if your slide actually is leaky - rather than perfectly aligned, you might choose to replace the pairs of tubes with new pairs that fit as they should.

It is on beat no-name stencil sousa. One side of the main tuning slide is leaking and the other side is tight. If you put just that leg in, you can feel it rocking in the outer slide. By my measurements, the top is slightly flared, so my guess is someone tried to "fix" it at some point by smashing it onto a tapered mandrel.

Trying to fix it without spending any money, since it will be given to the middle school down the road for a "show and tell" instrument to try to recruit sousaphone players for the marching band.

I thought about making my own expander by turning down rod stock on the lathe. Basically the same as the Wes Lee video that @York-aholic sent me.

[bloke]

If someone does use one of those expander tools - which is likely what you will choose to have happen, I would hope that they would do what I do when compelled to use one of them, pick only one of the two inside slide tubes, and render it very subtly barrel-shaped, so it's not made too large on the bow end nor on the tip end, and only grabs enough along the middle of the tube to add enough friction to not slip. If if your slide actually is leaky - rather than perfectly aligned, you might choose to replace the pairs of tubes with new pairs that fit as they should.

It is on beat no-name stencil sousa. One side of the main tuning slide is leaking and the other side is tight. If you put just that leg in, you can feel it rocking in the outer slide. By my measurements, the top is slightly flared, so my guess is someone tried to "fix" it at some point by smashing it onto a tapered mandrel.

Trying to fix it without spending any money, since it will be given to the middle school down the road for a "show and tell" instrument to try to recruit sousaphone players for the marching band.

I thought about making my own expander by turning down rod stock on the lathe. Basically the same as the Wes Lee video that @York-aholic sent me.

100% a slide expander candidate. Just take it to someone with a slide expander. Make sure they have the ones that are in the tuba size range. I think there's four that perhaps Ferree's makes and sells.

They might even have some tubing that fits that outside slide tube better than the one supplied by the factory. If they have as much crap laying around as I do, there's a pretty good chance of it.