[asid61]

Looks pretty solid all around.
Note:
1. Your shafts can be a bit longer to take full advantage of the bearings. Right now they only stick about halfway into them.
2. You could make the plates slightly larger if you want to add a plastic cover around it.
3. For the "powercoated" look, click on the beach ball up top, set the appearance to "polished aluminum" on the right, and click on the color right above black on the left. I've found that gives good results (credits to Chak).
4. What made you go with bolts and nuts over making the back plate tapped?
5. It wouldn't be too much trouble to make this shifting I think, given the space you have between plates. You might want to look into that.

That's all I can see right now. Overall it looks like a great job! Keep up the good work.