My base has longer slots to accomodate 40T pulley (or 36T pulley) and larger 3mm holes and the hex nut holes are tapered all so less cleanup needs to be done before using it.
Assembly instructions are here:
http://gr5.org/med/You can buy all the non-printable parts as a kit from here:http://gr5.org/store/
Technical
I sell all parts at gr5.org/store/:
40T GT2 pulley
20T GT2 pulley
55T GT2 belt
2x MF695 flanged bearings
5x40mm cylindrical pin
7x m3 nuts
m3 screws:
3x 32mm
1x 18mm
2x 15mm
4x 12mm (very important exact length to hold motor)