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Beetle B16 / B62 Gearmotor Mounts

posted Mar 10, 2012, 5:29 PM by Lewis Baumstark   [ updated Apr 24, 2012, 5:41 PM ]
The Beetle B16 gearmotors are nice, but frustratingly hard to build motor mounts for.  They have a "double-D" face profile that requires drilling a large hole, but the screw holes that hold it in are so close to the big hole that it's hard to get right.  The easiest way is to buy pre-made mounting plates from Kitbots.com.  I'm going cheap on this and, frankly, I'd have to re-design a lot to fit those plates.  So after some trial and error today, I found something that works reasonably well.

I have a dead B62 gearbox from a previous competition -- and it has the same hole pattern as the B16.  So I took the motor's faceplate off and popped the shaft out of it.  Then I tapped the shaft hole with an 8-32 threading tap (it's a little loose but not too much) and stuck a short 8-32 bolt in it.

I'm mounting these in 1/4" thick Aluminum bar.  When I go to drill the mounting holes for the motor, I start by drilling and tapping an 8-32 hole centered with the motor (i.e., where the shaft would protrude) and then screw my salvaged-faceplate-plus-bolt into that hole:


Then I can use the existing holes from the faceplate as guides for drilling.  Once those are done, I take off the faceplate and bolt and switch to a 9/16" drill bit, which I sink just a little into Aluminum bar -- just enough to accommodate the "double-D":


Finally, I make the center hole a little bigger so the motor shaft doesn't touch the sides and voila! Integrated motor mount:


Update, for those frustrated souls scouring the Interwebs looking for enlightenment on mounting these motors: I highly recommend using counter-sunk M2 machine screws to hold the motors in.  It doesn't show on this page, but I switched to counter-sunk screws later.  Well worth the trouble!
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