PCB surface tracker(pre-lim.)

This is a work in progress. I still have many tweaks to be made and is not ready for primetime.
I'm posting it to get input and seed some ideas.

So basically it's designed to run spring loaded on the Z axis of a milling machine and use a limit switch to signal the cam software that the milling bit is in contact with the copper clad board. I just redesigned the locking collar, since the first one was too tight. I have not printed it yet, but it's a portion of the vacuum collar, so should be g