To make the mandrels in the illustration, you may need the services of a carpenter. These mandrels must be turned on a wood lathe and carefully inspected for flaws. When I made these mandrels for the shop, I used 4x4's for the center of the tuba and F-tuba mandrels. This size is readily available at any lumber store. You may notice the discrepancy in the size between 4"x4" and the stated size of 3 3/4" . Due to factors unknown to man, lumber yards sell 4x4's and claim they are only 3 3/4" because they had to trim away the rough surface.To these 4x4's I attach the necessary amount of wood on all four sides to accomodate the taper produced after turning. It is only necessary to use white glue if you use untreated wood.
Although these mandrels are big and bulky, there is no better way to hold these low brass instruments while cleaning or repairing them. These mandrels, if carefully made, will do no damage to the horns. They can be mounted in a vise and set to a level appropriate for the technician.
I have found the above sizes to work on the widest range of makes and models. You may have to modify them if you are using them for E flat, D tubas.
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