Summary

A quick release mount to attach a Bosch Colt to 20x40mm extrusion rail (Shapeoko and similar).

This will allow you to remove the spindle for use as a trim router when you're not milling.

Also check out http://www.thingiverse.com/thing:989778, a laser adapter to mount a JTech Photonics laser module or similar into my quick mount.

Instructions

I printed all files out of PLA on a Makerbot at low quality with 20% infill. If deflection becomes a problem, I will have to print at a higher infill.

The pin holes were cleared out with drill bits until the pins fit. The pins have a flat on them so you can print them on their sides to increase shear strength.

My counter bores on the mounting holes are a bit deep for the M5x20mm screws I had so I added 3 M5 washers to each.

You may need to tweak diameters based on your printers shrink. On mine the collar clamps very snugly, and takes quite a bit of force to lock the cams.

Update:
I added a strip of Gorilla tape around the inside diameter of the mount. The compliance of the gorilla tape makes the inside of the mount grippier and tighter overall. After hours of milling work everything is still looking solid.

Update (1/8/16):
After a year of use, a failure of a holding tab caused the spindle to get hung up on a cutout, breaking the mount. I strengthened the main components to prevent future issues, and printed with a higher infill. See revision 2 versions of the "mount" and "arm". Please note that the assembly stl has not been updated as of yet. The photo with the black components shows the new updated parts.

Quick Release Bosch Colt CNC Spindle Mount