About this 3D model

This is a simplification. I added the Z stop bolt mount to the X end clamp, eliminating a printed part, some hardware and a source of failure. My clip on Z stop is easy to move accidentally. The bolt is a 6-32 x 2" and is tightened against the trapped nut. (4mm works, too.) The Z home is easily and accurately adjusted by moving the thumb nut. One turn of the 6-32 screw is .03125" The thumb nut is self threading when you screw it on, just keep it straight. The clamp still uses the M3 nuts in 4 places and either a M8 or 5/16" nut to match your Z lead screw. Refer to the old version to see the improvement: http://www.thingiverse.com/thing:13235