Mendel Pulley with 3 captive M3 nuts

This is derived from nopheads Mendel Pulley with captive M3 nut, but has been redrawn in openscad, and added more nuts for extra grip.

This part is also part of my OverlapStrap project which is licenced under GPLv3 see: http://www.gilesbathgate.com/OverlapStrap/
or checkout using

git clone http://www.gilesbathgate.com/OverlapStrap.git