Low cost CNC

Instructable using servo motors

We got our timing belts and pulleys from McMaster-Carr (but they are available elsewhere):
part # 6484K454 Trapezoidal Tooth Neoprene Timing Belt .200" Pitch, Trade Sz 770XL, 77" Outer Circle, 3/8" Wide
part # 57105K21 Acetal Pulley for XL-Series Timing-Belt for 1/4" & 3/8" Belt Width, 1.63" OD, 22 Teeth

Bearings and Collars
For the timing belt pulley bearings, make sure to get the extended inner ring ones so they don't rub against the shaft collars. You could also use regular ones with small washers on the inner ring. We used flanged ones to make mounting easier.


We got our timing belts and pulleys from McMaster-Carr (but they are available elsewhere):

part # 6462K12 Type 303 SS Set Screw Shaft Collar 1/4" Bore, 1/2" Outside Diameter, 9/32" Width
part # 57155K337 Miniature Precision SS Ball Bearing - ABEC-5 Flanged Shield, Extended Inner Ring, .25" ID, .5" OD

After building these, we noticed that Home Depot has ball bearings for patio doors, and these may work almost as well at a much lower price. Rather than mounting the bearing in a hole, you could put a couple bolts right through the outer plastic ring and bolt it right to an L bracket.