Improve side (long axis) motor mounts

[dbenamy]

Some of the screws don't have springs around them.

The springs that pull the gear teeth into the racks should be tighter.

The gears need to be carefully aligned with the racks for even wear.

[dbenamy]

The y motor closer to the middle of the shop is not moving well. That may be related to it not being mounted quite right.

[dbenamy]

Yes!!!! Y motion is working well now! We had a bad motor.

So the mounts are a big ad hoc now and could probably still benefit from a few more of the right parts. We can see whether that turns out to really matter.

I'll leave this open to track lining up the gears with the racks once we align the table in #7.