How to Machine a Pilot Bore Pulleys

[andy1989]

Looking for some advice on how to machine pilot bore pulleys.

I have a small lathe to drill and bore out the hole, but I'm not to sure how to hold the pulley without damaging the flange or teeth. Based on the drawings the hub is only 5mm, which seems a little on the small side for chucking up?
Also, any advice on how and where to drill the locking screw would be appreciated.

Alternatively, can you get 8mm taper lock bushes to fit NEMA 23 motors? Smallest iv managed to find is 9mm.

[Voicecoil]

I just gripped mine by the hub (push it right back against the chuck) and took it gently with good sharp cutting tools - no problems for my 20t AT5 pulleys..For the locking screw I filed a small flat, gently centre punched then drilled holding it across the flat faces in a machine vice.

[m_c]

I normally use a 4 jaw chuck, along with 4 spacers so you can grip onto teeth without catching the flange.

As for grub screw, if there's no wide enough boss, I normally just drill in the bottom between two teeth, then tap as required.

[Voicecoil]

Having machined some more yesterday, one more tip I omitted before: to get them central in the chuck, just shove a centre (live or dead) into the central hole: will also help with keeping it steady if the boss isn't very long.

[andy1989]

Thanks for the advice guys. Will give both a methods a try and let you know how in get on.