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.