Mitigate torquing in micromanipulator top rail

[InchoateArtichoke]

Micromanipulator top rail (up/down axis) has a tendency to torque when turned. Reducing this tendency will be especially helpful for the tethering setup.

Things to try:

• Conduct qualitative torque test with one nut vs two nuts
• Add in solid body where print supports usually occur in rail production (also removes need for support)