Tuning Slide Alignment

[andrew the tuba player]

Hi everyone.
I've noticed something that has become somewhat of an annoyance and I want to make sure that that is all it is.

The horn in question is my '09 Conn 52j. I've noticed that the tuning slides aren't parellel. The body tubing is but the slides are not. They seem to be slightly bowed out. Enough so that I have to push them together slightly to get them to fit back into their position. Some are worse than others but they all do it to some degree. The 5th valve slide on the back is the worst. I believe this is causing the the 3rd and 5th slides to be tight. All of the rest of the slides pull as smooth as they should but those two are very stiff. You can also hear them spring out when they are pulled out.

Is this something to be worried about or just something to live with? Its been that way since I pulled off the plastic. I thought it was just the slides being new and figured they we straighten as they spent time in the horn (a wear in if you will). But it hasn't gotten any better. I have never had this issue with any other horn.

I've posted a picture of the bottom 4th valve slide with one side lined up so you can see what I'm talking about. What I'm worried about is the slides wearing faster and irregularly and about the constant application and release of stress on the joints of the slides.

[tubari]

You can squeeze the two inner slides together to get the tubes to line up. This will take care of the "spread" alignment. As for the parallel measurement, ie. all 4 tubes being on the same plane, you should take it to a reputable repair tech to align these.

[toobagrowl]

One easy way to 'fix' slide alignment is to (if you don't mind 'messing up' the finish) put the slide halfway in, and put some torch heat on the crook where the slide legs connect until it "pops", then take the torch off. Wala.......slide alignment

[largobone]

You COULD try that...or just take it into your tech. He'll do an alignment, it'll probably cost you less than $25 and if he isn't that busy you could watch him do it and get back to practicing by the end of the hour.

EDIT: For 5-10 slides, it might cost a bit more, maybe a hundred or two. But worth it to ensure the longevity of your horn. One thing to note, a tuba should always come with slides pre-aligned (no wear-in period), you should have taken that up with Conn-Selmer as soon as you got it. Oh well, you didn't know, luckily it hasn't caused you too much trouble so far.

[andrew the tuba player]

Well at least it's an easy fix. As I said I've never had an issue with it until this horn. I'm glad it's not a build error or something like that. This is also my first new horn so I didn't know if that was a part of the process since all of my other horns were considerably older.

Thanks for the info.

[PaulMaybery]

Some situations are simple fixes, as with throwing some heat on the joints until they snap into alignment. Another situation comes to mind in which the outer slides not only are not parallel, they are spread wider at the top than at the knuckles where they come out of the valve cluster. To top it off the outer slides are braced with a solid one peace job, not one of the adjustalbe/telescoping varieties

Unfortunately it is not likely possible to change the knuckles. So. The brace needs to be removed and some how shortened the 3mm. A metal saw cut should have a sufficient kerf. The brace then needs to be silver soldered back together. This should allow the outer slides to line up.

Now to tackle the crook and the two inner legs. In this case the crook was the same dimension as the top of the preexisting outer slides. As it was, the legs lined up nicely with the outers, but the further it was pushed into the outer slides the more it began to bind.
The crook needed to be filled with pitch and bent inward to make up for that 3mm discrepancy.

After reassembly, it worked as it should. The problem was in the original assembly, as the knuckles were not fitted properly in the valve cluster before they were brazed. The brace and the tuning crook actually were the proper dimensions.

Of course a good lapping to smooth the slides will help, but in this case, the binding was too severe and the slide could never be adjusted on the fly. Yes 3mm can be too much.

The manufacturer's warranty, did in this case, cover the repairs. So if slide pulling is important to your performance technic, then by all means check the slides for parallel, and if there is a problem, make a claim to the manufacturer as to faulty workmanship.

Even if they are parallel, in most cases you will need to have them lapped to the smoothness that suits your needs. You can do this yourself with Brasso or Noxon. They have pumice in them and can gently lap brass slides as well as nickel (though nickle will take longer) I've done each of my slides around 3 or 4 times to step by step get them the way I want. It is time consuming and a repair tech could more easity perform the task with actual lapping compound. But if you have the time and elbow grease, it's not a difficult job. I always make sure to use a petroleum based oil, such as lamp oil, to swab the slides. The trombone cleaning rod works well. Be sure to keep swabbing until the rag on the rod comes out perfectly clean. Any residue can get into the valves and begin to foul them.

[andrew the tuba player]

Ok. I will looking into the body tubing as well. I know the slides themselves are off because you can see it on the longer, more narrow slides. Slide pulling has never been a huge part of my playing technique. But it is an annoyance when cleaning or removing water. A lot of water collects in the bottom 4th slide and being a smaller and very tight bend it doesn't take much to start effecting the sound.
Is build quality an issue with newer Conn - Selmer instruments? I know that all of my older Conns (mid '60s and older) have been built extremely well. I know this horn feels a lot more fragile (probably do to different metals used). It should be noted that this is the only issue I've ever had with it other than the shipping company doing a number to the case and lead pipe.

[Dan Schultz]

Interesting question that does not have a simple answer. You cannot assume that either the outer tubes or the slide are parellel... even with a new horn. Thet pretty much eliminates correcting the problem by heating up any solder joints to 'let things settle in'. It's always nice to know what the distance between the two slide legs SHOULD BE to start with. Any dent work on a crook can change this dimension. Starting with a new slide of known good quality can help. So can a new crook. Assemble the slide first with it laying on a flat surface with the 'legs' parallel. Once the slide is properly assembled... the outer tubes are slipped on and that assembly is fitted to the horn.