optical endstop mount and adjustable target

First of all this is my first posted 'thing'. When I made it I wasn't thinking of posting it, so sorry there aren't any pics of the parts not assembled or of the assembly process.

I used a brass 3mm threaded insert in the target piece pushed in with a soldering iron, but you could probably just as well thread the screw directly into the plastic. The screw itself passes through the top, with a washer under the head, another washer, then a fiber lock nut. Tighten the nut until there is no slop in the screw, but still easy enough to turn. The holes in the lower part are to be a press fit for the brass rods, and the holes in the upper part are a slide fit. I had to clean the holes up slightly with a rat tale file for the correct fit. I used 3mm brass rod, but you could use whatever fits. The top unit is then bonded to the X carriage part using plastic solvent. The stuff used for making plastic models and can be found at hobby shops (not the stuff in the tube, this stuff us water thin a