[Degrom]

The T5 pulley has an ID of 6mm and Nema 23 has an OD of 6.3mm.

Was just wondering if that little 0.3mm was for press fitting it...

[chrugel]

The T5 pulley has an ID of 6mm and Nema 23 has an OD of 6.3mm.

Was just wondering if that little 0.3mm was for press fitting it...

0,35mm is not little when it comes to press fitting!
I had a pulley that was a little bit to big and what i did was to shimis it with thin metal plates and then press fitt it. I believe this was in the range of press fitting 0.0~ somethig and it took about 10.000N to get the work done.
I cant imagine what it's going to take to get 0.3 mm done.
If you have access to a lathe is is not hard drilling up the pulley. It is a little bit tricky getting the excact size.
If i is a dual shaft motor it is a lot easier to turn down the motor shaft. I've turned down a couple of motorshafts without even dissassembeling the motors. If it is not a dualshaft it can be rather tricy and you have to take the motor apart.


chris

[irving2008]

Do not take the motor apart if you want it to work after... steppers are very touchy about the magnetics - if you remove the rotor you may find the stepper isnt as powerful as it was before.

Always make the pulley fit the motor... drill it out on a lathe or mill or get a get a 6.35mm tapered reamer and open out the pulley bore that way...

[LeeWay]

If you have several 1/4" drill bits, find the smallest diameter one. They will likely vary a bit. Then just use that to increase the hole size. Easily done on a lathe, drill press and yes, even by hand. You are effectively only reaming to size.
A solid motor coupling to a screw would be more critical, but for a belt pulley, incredible accuracy just isn't needed. Close is good enough.

[johnmac]

If your pulley has flanges to keep the belt on, be careful with it. The flanges bend and breaks off easy.

John

[Mike Nash]

A solid motor coupling to a screw would be more critical, but for a belt pulley, incredible accuracy just isn't needed. Close is good enough.

Maybe, but on my X2 mill, the pulleys were not concentric with the shafts/screws due to a slightly loose fit. (I bought the mill already CNCed so I don't know whether the pullies were drilled/bored.) Anyway, that was the source of the 0.001" "drunken thread" symptom I was having. I had thought it was the ballscrew, but it was the pulley on the ballscrew.

[UUU]

I've rebuilt my machine with new steppers so was faced with mating existing pulleys to new motors. I was fortunate in finding some steppers with a 6mm shaft, so that part of the problem didn't exist.

I cross-drilled the pulley and through the shaft and fitted a roll-pin.