Mechanical design for an optics assembly:
I made an adapter plate between the XYZ translation stage and the 2"/1" lens-rings. The XYZ stage has a 50 mm x 50 mm M6 thread pattern, and the optics are mounted on a straight line with M4 screws through the adapter plate. M6 countersink is 12mm diameter 7mm deep, while the M4 countersink is 8mm diameter and 5mm deep.
In real life this looks almost like the CAD model: