65mm Spindle mount

The mount is designed to fit on 4 slot 80mm aluminum extrusion, holes are spaced at 20mm centers and will hold at 65mm diameter spindle.

The clamp bolt is sized for M5 and the 4 holes are M3, designed around Allen head bolts.

This is my first attempt at making a mount for a CNC spindle so any comments on improving it are appreciated.

**Update**

I have now uploaded version 3 of the clamp.

V3 changes:
* Increased the depth of the clamp ring from 10mm to 15mm
* Pushed back th