Busted valve stems

[Shockwave]

This happened today...



One broke off when my tuba bumped into a coffee table. The other snapped when I tried to unscrew another valve stem to see which end of the screw was soldered. It turns out that both ends appear to be soldered, but it basically fell apart in my hands without applying much torque at all.

How should I go about fixing this? I was going to drill a nice hole on the lathe and use a screw extractor, but the the solder makes the job a lot more tricky since I've never applied heat to a valve piston before. Drilling and tapping a larger thread for new stems is a possibility. A mickey mouse repair with epoxy is possible too. How much would a repairman charge?


-Eric

[Shockwave]

The valves are from a big huge Holton recording bass that I am hoping to sell. I took it out of the case today to take some pictures and ended up breaking off a valve stem before I even got the camera ready. As it is I have to mention the missing spit valve, the bent leadpipe, the loose top bow guard, and the big leak where the bottom bow attaches. Adding two broken valve stems to the list is a bit much.

Now that I know left hand drill bits exist I just have to have one!

-Eric

[Bob Mosso]

Just as Bloke explained. I recommend making a "V" block out of wood, hold the piston in a vise with the wood, use a drill press or mill so everything stays straight and steady.

[Dan Schultz]

After the last game of the season, I had a valve stem just fall into my hand. No particular reason that I could figure out. But there it was broken cleanly in the same place as the pic above. The local repairman that the college went through just got a new valve, said it was more cost efficent.

Hmmm... I suppose there are extreme cases, but I can replace several broken stems for the price of a new piston.

[Haugan]

"bloke" gives great advice for the proper procedure, but if you've got limited experience machining, "harder than lead based" solder, or "something else pops up in the procedure", you may end up wishing you paid a repairman the $25-50.oo a repairman will charge you for the labor AND valvestems. If you're adventuresome, go ahead - working on your own stuff CAN be satisfying........proceed with caution.