trimming/shaving a mpc. shank?

[jon112780]

Can you do this and is it a good idea?

I mean, just taking a little off the circumfrence of the shank, to go from a bass bone shank to a euro... I realize that the metal in the shank would be noticeably thinner, but is this even a good idea? I'm asking because the mpc. in question is not easily bought over here in the US(usually on back order from Dillons), and purchasing and shipping one from Germany would take up to a month.

And I need it 'real' soon. Is this something the local repair guy can do in a couple of minutes? Or should I just go ahead and order and wait a month?

[OldsRecording]

I once 'trimmed' a Schilke 51D from a bass shank to a tenor shank with a pair of pliers. It's not pretty, and it is not something I would do nowadays, knowing what I know now, but yes, it does work.

[Dan Schultz]

I once 'trimmed' a Schilke 51D from a bass shank to a tenor shank with a pair of pliers.

[tbn.al]

The curse of the Besson 943 is that the mp recievers are made to accept those Dennis Wick things. When I try to play a Schilke it is about 20 cents flat. I just chucked them up in my drill press using a fixture I made and turned them down with a big Bastard file. I went very, very slowly with almost no pressure and checked with a micrometer every little bit to match the taper with the Wick. When I got to within 25 to 50 thousandths I wraped the file in 150 grit emory paper and graduated to 400. The final polish was with steel wool. I had my main 59 and 60 gold plated afterwards and they work great. I also did a Bach 30E tuba mp this way but I got it a bit to small. The answer is plunbers tape. Looks terrible but it actually works great. You also have to address the inner taper. I copied the Schilke bore taper onto a hard maple dowel by using grinding compound in an old beat up 60. After the outside was finished I cut shank to length using a tubing cutter and then redid the bore with the maple taper and more grinding compound. Not perfect but very close. I found out later that Warburton would custom make them for me for $200. Had I only known.

[Art Hovey]

I have done it myself with a flat file. If you keep rotating the mouthpiece while filing you can remove material pretty evenly. I also watched a professional repair man trim down the shank of a tuba mouthpiece made in Germany so that it would fit a King receiver. He wrapped some leather around the rim, put it into the chuck of a lathe, and filed it by hand while the mouthpiece rotated. It only took a few minutes. Either way, you have to check the fit a few times by putting the mpc into the receiver and twisting it around. It's easy to see where more filing is needed. When you get it right it's easy (but not necessary) to smooth the shank with steel wool. A skilled machinist can also add a sleeve to build the shank back up if you go too far, but that's not so easy.

[eupher61]

It's a lot easier to do with a lathe, but make sure the repair guy doing it knows HOW to do it. I had a mouthpiece all but ruined by an idiot who didn't, although he had the machine, and it cost me $$$ to replace the mpc that was copied.

[Todd S. Malicoate]

make sure the repair guy doing it knows HOW to do it.

I wonder how one does that in a tactful manner. I can't imagine a more disrespectful question to ask a top-notch repairman or a more important one to ask a novice. I am, however, relatively sure that you'll get the same answer from both of them..."Don't worry, everything will be fine."

Todd S. "who wouldn't know how to keep up-to-date on various repair persons' credentials or training" Malicoate

[OldsRecording]

I once 'trimmed' a Schilke 51D from a bass shank to a tenor shank with a pair of pliers.

Honestly. I just grabbed the shank with the pliers and twisted them around until it was the desired size and shape. Yes, I was young and foolish at the time. I will post a picture as soon as I replace the battery in my camera.

[tuba kitchen]

My tuba repair guy did it at least 3 times for me and it worked....

[euphomate]

My repair tech has just done what bloke suggested. My Denis Wick mouthpiece is fine in the Besson Sovereign EEb, but sticks out an 1" too far in the Willson 3400. That means the Willson blows flat until it warms up, and being a heavy horn that can take a bit of time, particularly in cooler weather. No probs now, a spell in the lathe means I'm on the spot early, and receiving nice smiles from the Director (a classy blonde BTW whom I will do anything to please). Well, almost anything.

[Dean E]

A trained machinist will know how to set up the compound rest on a lathe in order to turn the proper taper with a single point tool bit.

The proper taper angle varies with the horn's receiver. Some shank angles are claimed to be a Morse taper, while others are close, but not exactly a Morse taper. Morse tapers vary according to the diameter, but are approximately 5/8 inch per foot. Some other standard tapers are "Brown & Sharpe" and "Jarno." The web has lots of sites explaining the specifications. Some instrument manufacturers use non-standard, proprietary tapers.

The receiver in a particular horn may have become distorted over the years. When modifying a mouthpiece shank to fit a particular horn, one practice would be for an instrument technician to solder a new receiver to the leadpipe. An alternative would be to use a properly-tapered reamer to refinish the receiver. These reamers can be expensive.

A trick used by skilled machinists when hand-matching parts is first to apply a very thin coat of artists' "Prussian blue" oil paint to the good part. Secondly, the part to be matched is touched lightly to the good part, which causes the blue to rub off onto the high spots of the piece being mated. Thirdly, thusly identified, the high parts of a mouthpiece shank may be removed in a lathe with a file or emery cloth.

A final consideration is to avoid either interference or an excessive gap at the tip of the mouthpiece shank.