Searched, but didn't find this discussed here previously. I'm upgrading a hobby-level CNC router (a Shapeoko 3) to have wider belts (it came w/ 6 mm GT2 (2 mm)), I'm going up to 9 mm (otherwise same specs).
I ordered new pulleys and belting from SDP/SI, but when I went to install them was concerned that the end of the motor shaft (6.35 mm diameter NEMA23) is inset from the end of the pulley by almost 5 mm (4.88 mm). With the previous pulleys, they were flush with the motor end (but probably should have been slightly off to allow the belt to run true).
Is that too great a distance? What would be the maximum distance that the pulley could be off the shaft? What guidelines are there for this? How is it determined? (I've tried searching but haven't been able to find anything – am I not using the correct terminology?)
What is more important, that the belt run true or the pulley be on the shaft? There's only a couple of inches between the idlers (pairs of flanged bearings on M6 bolts) and a great deal of engagement.
The pulley in question is SDP/SI part # A 6A51-020DF0908.