What's the best way to lap valves?

[tubaman5150]

I need to learn how to do this at home. Any of you repair gurus wanna help me out?

[Dan Schultz]

I need to learn how to do this at home. Any of you repair gurus wanna help me out?

Lava soap and lots of elbow grease.

[Matt Good]

I am NOT a repairman but I do own a bunch of tubas.

First, you should consider leaving this job to a qualified repairman. This is a messy job and you will need to eventually flush the tuba with lamp oil to get out ALL the lapping compound when you are done.

If these are pistons that are sluggish or sticking, there is a good chance that your casings are too worn and the pistons are not centering in the casing. Try using a heavier valve oil and see if that helps. In my opinion, lapping a set of valves down is counterproductive and will actually take several years away from the lifespan of a valve set. The ultimate solution is to have your pistons replated and then lapped back into the casing.

Hopefully Bloke, Matt Walters or Lee Stofer can give you better advice.

[Daniel C. Oberloh]

It never ceases to amaze me, even after more then twenty years of repairing and rebuilding instruments that there are always folks who are willing to roll the dice and risk damaging or destroying there instrument. Sorry about my bluntness but why do you feel the need to lapp your valves? Do you have a clue about what you are doing? do you know what the real problem is with your valves or are you just guessing?

No disrespect to Dan Schultz but I would strongly recommend against the use of Lava soap as pumice is not the proper material for such work in spite of what has been taught to novice Repair Techs for years, it will imbed itself into the soft brass casing wall and cause more problems then you want to deal with. Grease based Clover Leaf (600 grit) and Ferrees Ultra Smooth are more appropriate for this sort of work. Its machinists work so use what they use not something you find on the edge of the sink. If you are not experienced with the process and my guess is that you are not, leave it to a skilled professional and you will avoid the risk of screwing up your valves. You can do so and spend a little $ or put on your blindfold, go for it yourself and pay for the rebuild $$$$$$ after you have made a pigs ear of the valve assembly. Ether way, knock yourself out.

just my 2¢ worth (probbly less).

Daniel C."who does not feel he is obligated to save others from them selves but still feels compelled to do so"Oberloh
Repair tech to the stars (Floyd and Emma Starr formerly of Orting Wa.)
Oberloh Woodwind and Brass Works
www.oberloh.com

[tubaman5150]

It never ceases to amaze me, even after more then twenty years of repairing and rebuilding instruments that there are always folks who are willing to roll the dice and risk damaging or destroying there instrument. Sorry about my bluntness but why do you feel the need to lapp your valves? Do you have a clue about what you are doing? do you know what the real problem is with your valves or are you just guessing?

No disrespect to Dan Schultz but I would strongly recommend against the use of Lava soap as pumice is not the proper material for such work in spite of what has been taught to novice Repair Techs for years, it will imbed itself into the soft brass casing wall and cause more problems then you want to deal with. Grease based Clover Leaf (600 grit) and Ferrees Ultra Smooth are more appropriate for this sort of work. Its machinists work so use what they use not something you find on the edge of the sink. If you are not experienced with the process and my guess is that you are not, leave it to a skilled professional and you will avoid the risk of screwing up your valves. You can do so and spend a little $ or put on your blindfold, go for it yourself and pay for the rebuild $$$$$$ after you have made a pigs ear of the valve assembly. Ether way, knock yourself out.

just my 2¢ worth (probbly less).

Daniel C."who does not feel he is obligated to save others from them selves but still feels compelled to do so"Oberloh
Repair tech to the stars (Floyd and Emma Starr formerly of Orting Wa.)
Oberloh Woodwind and Brass Works
www.oberloh.com

I am not totally inexperienced with instrument repair and I have just recieved a shippment of loctite clover silicone carbide lapping compound.
I have a fairly new valves and one of them had some burs on the inner casing that caused some major scratching and sticking. I have removed the burs, but It still sticks badly. That's why I need to lapp it.
I have no funds to send my tuba away to a qualified repair person and there is no one competent nearby. I figure this is a good time to learn to lapp valves properly. I appreciate your concern, Dan, but didn't you have learn these things from somewhere? I posted on Tubenet in the hopes that I could get some pointers from the gurus, but I have spoken with with few other brass techs about how to do this. I feel competent enough to do this myself. Since I am going to do this anyway, I sure would appreciate some advice from a top notch repairman such as yourself.

[windshieldbug]

What's the best way to lap valves?

Is that anything like getting a lap dance?

[Daniel C. Oberloh]

I see, In that case, before you do anything, focus on removing the valve guide key first and check the piston action with the guide out. Many new horns have guides that are a little snug or just poorly fitted. Get a small flash light and check the the key guide way in the cylinder wall. if the piston runs smoothly without the guide key, then you have found the problem. minor adjustments to the key with a pillar-file should do the trick. working the valve with key in place, with a small amount of lapping compound in the key way will smooth and improve the action. Be sure that after word you get all the lapping material out of the valve. Be sparing with the lapping compound and the amount of lapping you do, work slowly. you don't want to over do it. good luck.


Daniel C. Oberloh

Oberloh Woodwind and Brass Works
Saving the world, one horn at a time...

[tubaman5150]

I see, In that case, before you do anything, focus on removing the valve guide key first and check the piston action with the guide out. Many new horns have guides that are a little snug or just poorly fitted. Get a small flash light and check the the key guide way in the cylinder wall. if the piston runs smoothly without the guide key, then you have found the problem. minor adjustments to the key with a pillar-file should do the trick. working the valve with key in place, with a small amount of lapping compound in the key way will smooth and improve the action. Be sure that after word you get all the lapping material out of the valve. Be sparing with the lapping compound and the amount of lapping you do, work slowly. you don't want to over do it. good luck.


Daniel C. Oberloh

Oberloh Woodwind and Brass Works
Saving the world, one horn at a time...

Thanks a million, Dan.

[Tubaryan12]

No need to get all lathered up.... just get a good pair of sneakers and keep a slow steady pace. They'll tucker out after the first mile......

[Dan Schultz]

No disrespect to Dan Schultz but I would strongly recommend against the use of Lava soap as pumice is not the proper material for such work in spite of what has been taught to novice Repair Techs for years, it will imbed itself into the soft brass casing wall and cause more problems then you want to deal with.

Daniel C."who does not feel he is obligated to save others from them selves but still feels compelled to do so"Oberloh
Repair tech to the stars (Floyd and Emma Starr formerly of Orting Wa.)
Oberloh Woodwind and Brass Works
www.oberloh.com

It's soooooo nice to have a real expert on the forum

[Dan Schultz]

...That's a picture of my Siamese twin.

Good God THAT looks like the missing link