View Full Version : drive pulley bore change
05-19-2009, 09:13 AM
I am changing the steppers on my bp.The originals were 5/8 shafts.The new steppers have 1/2". Do you bore the pulleys out and bush them or do you buy new ones.If new then where do you find them.
05-19-2009, 03:11 PM
The previous one I did as well as having to go up in size I also had to space it out more so I made a top hatted bush up where the larger diameter carried the two set screws at 90 degrees to one another and the smaller diameter went into the existing pulley.
The one I am doing at the moment has a type of 'taperlock' fitting and because the motors I am using are 14mm shaft and I need to go to 5/8" I have decided to make new 'taperlock' inserts as the sleeve will be very thin.
05-19-2009, 05:04 PM
This little motor is being a pain. The shaft is way shorter also.I am leaning towards a taper lock pulley since it is so short.The original set screw was between the pulley and the motor.The new one is too short so the set screw will have to be in the center of the pulley teeth.The taper lock will get a very good fit that will be able to remove if needed.Hopefully never but you know how that goes...
Also the stepper has a large flat milled on the shaft instead of a key. I would have preferred a key for fear of the pulley working on a set screw and loosening.
05-19-2009, 05:20 PM
My motors are 14mm but plain, I put a tight fitting paper washer over the shaft and then silicone seal, then milled a keyway in them with a carbide slot drill.
The reason for the washer and silicon is that a while ago on a gear hobber I got loads of crap drawn into the motor by the magnets.
No idea how it got past the bearings but it did and didn't want to take the chance again.
05-19-2009, 06:26 PM
The seal is a good idea. I was himhawing about cutting a keyway. I am leaning towards making a 1" od x 1\2 id bushing.That will give me enough meat to put a couple set screws in the bushing against the shaft.Then I will bore the pulley and key it and the bushing opposite the set screws.
I will install the bushing on the shaft and then install the pulley over it with a little shrink and maybe a couple grub screw on the split line.
Ill have to do this 3 times. I tried to price taper locks but I must have a different pitch than grainger has.They dont list what I have.