Loose F tuning slide

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rmb796
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Loose F tuning slide

Post by rmb796 » Tue Nov 24, 2020 10:49 pm

Hi Everyone,
I am playing a Bach 42G* which I really like. However , the F tuning slide was never very tight and over the past year it has begun to creep down (in) as I play. I am using the Hetman #8 slide grease but it seems to get diluted rather quickly and soon (week) the slide starts to creep in again. I am using the Hetmans #12 Rotor Oil for my Thayer valve and hate to use a tuning slide grease that might not be compatible or gum up my valve.
Any suggestions would be appreciated. Also, how would a tech go about making the slide tubes tighter?

Thanks and hope everyone has a nice Thanksgiving. Been a tough year...

Randy
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BGuttman
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Re: Loose F tuning slide

Post by BGuttman » Tue Nov 24, 2020 11:10 pm

Is Hetman 8 the heaviest grease? If not, get something heavier. You may be a candidate to use anhydrous lanolin.

One other technique I have seen is to put an O-ring on the slide tube and move it so it fits at the joint of the slide and socket. You may only need one.

If you take it to a Tech, he will try one of two things:

1. He may spread the tuning slide legs just a bit so that the slide grips the socket.

2. He may make a slight bulge in the tuning slide so that it fits a little tighter.
Bruce Guttman
Merrimack Valley Philharmonic Orchestra
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Burgerbob
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Re: Loose F tuning slide

Post by Burgerbob » Tue Nov 24, 2020 11:36 pm

The male legs of the tuning slide probably need to be expanded a tiny bit. It'll seal better that way, too.
Elow
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Re: Loose F tuning slide

Post by Elow » Wed Nov 25, 2020 12:38 am

Don’t do this
I’ve had a few horns like this, normally pretty simple for someone who knows what they’re doing. There’s a tool called a slide expander that just slight expands the slide, but could also expand it too much to where it doesn’t fit. I like the flare the very end so that it’s tight the entire way.
Last edited by Elow on Wed Nov 25, 2020 10:28 am, edited 1 time in total.
hornbuilder
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Re: Loose F tuning slide

Post by hornbuilder » Wed Nov 25, 2020 7:28 am

If your tech suggests "spreading the tuning slide legs" or "making a slight bulge in the tuning slide", take it to another tech! Neither of those techniques corrects the problem.

The correct method of fitting a loose tuning slide is to put the male slide tube on a snug fitting slide mandrel, then burnish the entire tube with a polished steel burnisher or roller. This will expand the entire part evenly and consistently. This process is done in stages, testing after each "pass" to see how the slide feels. Once the fit is at the desired stage, a light sand of the tube is done with fine sandpaper to give it a smooth finish. Clean, relube and you're done.

Slide expanders are also NOT the right tool for the job. Expanders leave a zig-zag pattern of expanded metal on the tube. Again, if the tech suggests using one, take it somewhere else!

Finally, simply expanding the very end of the tube still leaves the horn with a loose tube.
Matthew Walker
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Bass Trombonist, Opera Australia, 1991-2006
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BGuttman
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Re: Loose F tuning slide

Post by BGuttman » Wed Nov 25, 2020 9:47 am

Thanks for your comments, Matt. I was hoping one of the good techs on this Forum would respond (and set me straight!).
Bruce Guttman
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Re: Loose F tuning slide

Post by Elow » Wed Nov 25, 2020 10:26 am

Welp, that sounds like the better way. I’ll try that next time, a little confused though. Do they not achieve the same thing?
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Re: Loose F tuning slide

Post by BGuttman » Wed Nov 25, 2020 10:40 am

Matt's solution is basically a rebuild of the tuning slide to do what should have been done at the factory. The legs are too small for the sockets so you need to make them larger. A properly burnished bulge near the ends of the tubes might make things better, but it will still be easy to jam the slide if you don't pull it straight due to the odd fit.

The bend and bulge are "quick and dirty" fixes, not good permanent ones
Bruce Guttman
Merrimack Valley Philharmonic Orchestra
"Almost Professional"
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Re: Loose F tuning slide

Post by hornbuilder » Wed Nov 25, 2020 12:50 pm

Burnishing the entire length of the tube gives a good fit over the entire length of the part. This can be done with the slide assembled, there is no rebuilding required.

Expanders leave zig zag ridges of larger diameter, so it is only the tops of the ridges that secure the tube.

Expanding the very end of the tube will obviously only fit the very end of the tube. Pulling the inner tube in and out a couple of times will result in the slide being loose again, because it is such a small bearing area. The tube will also wobble, increasing the chance of the tube "cocking" and bending the end over.
Matthew Walker
Owner/Craftsman, M&W Custom Trombones, LLC
Bass Trombonist, Opera Australia, 1991-2006
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Re: Loose F tuning slide

Post by Bonearzt » Wed Nov 25, 2020 4:50 pm

As Matt mentioned, get the tubes fitted correctly!!

Skip the heavy grease and mis-alignining the slide!! The heavy grease, IMHO, may isolate the slide from the horn and not allow it to resonate as one unit.
The alignment spread and o-rings are just band-aids that don't really address the issue!


Eric
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