Material strengths for mounting plates

[Jonathan]

Finally someone using pulleys from the start :tup:

The second version (I think there's another picture I posted somewhere already) involved a pocket milled into the material ... whether a pocket like this would substantially weaken the mount or otherwise weaken it in a way that makes it pointless, and what thickness is actually needed for a decent motor mount?

Sounds familiar, here's one I made earlier:



That was from 5/8" thick aluminum, motor is resting on about 2mm thick which is plenty as the 'wall' around it which is the full thickness supports it. It would be fine with say 1/2", but that needed to be thicker to fit a big bearing. I've made the pocket longer to allow changing of pulleys without changing the belt. You'll need some adjustment anyway to tension the belt.

You should mount the bearing as in number 2 as that allows freedom in the plane of the motor mount so you can get the screw aligned perfectly.