I did this (following Dan Schultz's suggestion) for my 1924 Buescher horn. About the time you're doing the third valve, you've figured out how to do it reasonably well.
It has worked great. Dan suggested 3 mm. cheesehead nylon screws (of which I now have about 90 extras) -- which required drilling out the holes and tapping them. But it was all simple, and well worth the effort.
If you can get the delrin stuff, it may be better -- but good luck on that.
Gary Merrill
Wessex EEb tuba (Wick 3XL)
Amati oval euph (DE LN106J6Es)
Mack Brass euph (DE LN106J9)
Buescher 1924 Eb, std rcvr, Kelly 25
Schiller bass trombone (DE LB/J/J9/Lexan 110, Brass Ark MV50R)
Olds '47 Standard trombone (mod. Kelly 12c)
I don't know if he still carries them, but bloke used to sell delrin valve guides. Try a search for "RESIN MATERIAL THREADED VALVE GUIDES".
Alternatively, any qualified tech should be able to order them from Allied
"Nylon guides are MW and available from Allied Supply. Part No. MW123 They are metric thread and fit most any screw-in guide coming out of Europe." (if these are not on back order ?)
or from Krauss Music (but their web site says therse are on a long back order)
I am following this thread closely, with hopes that the process is easy enough for a novice tubist to attempt. If the screws work for you, I would be happy to liberate/purchase a few screws from your stock and try the same on my Conn.
Matt Walters (at Dillon) changed my tuba from metal to nylon guides. The horn is much quieter now. Matt said he doesn't see any more likelihood of problems from properly installed nylon guides than metal.
