Lapping pistons

[arpthark]

OK, tell me if I am crazy for giving this exchange an (internal) side-eye:

Trumpet player in a group I am in had a sticky valve. Took it to a repair guy who is NOT a brass specialist. At the next rehearsal, trumpet player says "I can't believe it; the 1st piston needed to be lapped!"

I am trying to determine if this is a person I should visit to take my tubas to, so I wanted a bit of input:

In general, isn't lapping pistons kind of a last-resort thing? I am sure it depends on a case-by-case basis, but speaking generally. I would think checking on things such as slightly twisted slide tubing might be the first thing checked before material is removed..?

and heck, I didn't really pry about this, so maybe that was considered, but it seemed like it was a fairly quick visit that yielded some immediate results via lapping.

I'd like some work done to my Eastman but I might just drive down to Dillon or up to Osmun to get it done.

[bloke]

They probably barely damaged the casing (heavy-handed grasping of the adjacent slide assembly - or LAYING THE INSTRUMENT DOWN ON THE #2 SLIDE - MASHING IT IN TO THE CASING), dropped the instrument a short distance, or man-handled the bottom valve cap.

Brass bends easily.

Sometimes/some-people can figure out just which place was damaged (and how) and (if they have a smooth-surfaced-enough tool) repair that part of the casing without working the valve back in with some super-fine abrasive...but repairing PLUS a brief lapping routine might be a better idea.

I didn't see that person's trumpet / I don't know the repair person.

You solicited "words", so here are some. ↑

[bloke]

Sometimes, valves can be made to behave (simply) by "lapping" them with nothing but a generous coating of oil...

' same somewhat-aggressive procedure, yet no super-fine abrasive compound added.

[2nd tenor]

I’m not sure that someone needs to be a ‘brass specialist’ to do a good job, they just need to be competent - a term that covers a raft of stuff - aware of their limitations and determined to do a good job.

It strikes me that in whatever endeavour a ‘fixer’ can solve one problem and at the same time cause other damage.

[arpthark]

I’m not sure that someone needs to be a ‘brass specialist’ to do a good job, they just need to be competent - a term that covers a raft of stuff - aware of their limitations and determined to do a good job.

It strikes me that in whatever endeavour a ‘fixer’ can solve one problem and at the same time cause other damage.

I agree that they need to be competent. That almost goes without saying. I have had bad experiences at smaller shops with no brass repair specialists on staff -- self-purported "general band instrument repair" folks. I'd like to avoid that again if I can. I will name no names, but we are talking misaligned valves, wrong-sized parts, all kinds of stuff. They had great reviews online.

Point being, I have some world-renowned shops that are a few hours drive away (Dillon: 3.5-4, Osmun: 1.5-2), but this person is within a half hour's drive, and I am trying to determine whether the methods I hear about them using are in fact kosher in the eyes of other repair folks and if I want to have them fool with my tubas.

I will ask some other local folks for input and experiences.

[2nd tenor]

I’m not sure that someone needs to be a ‘brass specialist’ to do a good job, they just need to be competent - a term that covers a raft of stuff - aware of their limitations and determined to do a good job.

It strikes me that in whatever endeavour a ‘fixer’ can solve one problem and at the same time cause other damage.

I agree that they need to be competent. That almost goes without saying. I have had bad experiences at smaller shops with no brass repair specialists on staff -- self-purported "general band instrument repair" folks. I'd like to avoid that again if I can. I will name no names, but we are talking misaligned valves, wrong-sized parts, all kinds of stuff. They had great reviews online.

Point being, I have some world-renowned shops that are a few hours drive away (Dillon: 3.5-4, Osmun: 1.5-2), but this person is within a half hour's drive, and I am trying to determine whether the methods I hear about them using are in fact kosher in the eyes of other repair folks and if I want to have them fool with my tubas.

I will ask some other local folks for input and experiences.

I had my Tuba repaired by a guy that I trusted, he wasn’t cheap but he did a good job and he did the work in front of me while I waited. The journey there and back home was three hours plus in total and I don’t regret spending that travelling time. Tubas are expensive, sometimes you have to live with paying more than a reasonable rate for a good job - I don’t like it but that’s life.

As for your local guy maybe visit him with some small and simple task and get a feel for what he’s capable of … or not capable of. Will he do work whilst you wait and watch, if not then a second trip is involved and that’s all additional time.

Good luck.

[bloke]

The most dangerous pistons to lap are those m a w pistons, because they are flexible/delicate. Lapping requires sideways pressure in all directions while up-and-down and round-and- round forces are also in play. I'm glad that the first set I ever had to fit to an instrument were the ones that I fit to my home-built Holton, so I know what to expect in the future when doing those for customers. A previous set that I owned dropped right into a C tuba, and just playing for an hour eliminated all issues... so no lapping.

I am nearly always guilty of going off on tangents, and this next paragraph is no exception:
I wasn't particularly interested in using those valves in that instrument, but - even though the plating on the OEM King pistons looked fine - those pistons and those casings are at least a quarter century old, and those m a w pistons were barely too large to drop into those old casings, so that gave me an opportunity for a factory close (or even better) fit on an older valve section without having to pay these higher post-Anderson prices for a valve rebuilding job, and nor did I have to take that very complicated, precisely-aligned, and custom-altered King valveset back off the instrument for such a rebuilding job. Finally, I bartered that piston set for some repair work.. so everything was really good, regarding this decision and action.