Does anyone make a 38mm to BT-70 centering ring?

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J Blatz

Well-Known Member
TRF Supporter
May 8, 2010
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I am looking to build a souped up USR Piston Stager with an H45 in the booster and some kind of long skinny 24mm up top (maybe an old AT G or the Ellis F20). Problem is that the booster comes with 29mm mount.

Do you guys know where I could get centering rings to center a 38mm tube in the BT-70 airframe?
Balsa Machining has a lite ply centering ring listed that is 2.175 OD x 1.637 ID, BT70 to BT60. But 38mm motor tube is 1.635 OD, so this ring would probably be too loose. You could contact them and see if they can custom make them for you. I have made similar sized plywood rings with hole saws, my woodlathe, and a Dremel.
We could possibly whip a couple out if you need. Whatever it takes to get ya up there!