Lego-Compatible Pulley Wheels

I've been searching a few sites for a pulley wheel for lego which I could use for pulley/belt gear applications, found none, so I have created this piece, there are 2 wheels:
- one of 2 cm diameter with +2 mm on of walls on the side to hold the pulley cord/belt in
- another of 4 cm diameter with +2 mm on walls again

I advise caution about the rotation and printer settings, 2 mm can prove to be quite an overhang if you lay the wheel down, also the axle socket is quite exact, if you wish for a bit larger tolerance, you wouldn't do harm by scaling it by a reasonable factor.