Quill Drive Reduction

[HimyKabibble]

I'm about to build a quill drive for my BP clone. I'll be using a 5/8" 5-pitch ballscrew, and probably a stepper motor. I have the impression most people use rather large steppers (800-1200 oz-in), and 2:1 or better belt reducers. Problem is, I can't for the life of me see the need to any reduction on there. I'd like to get 150 IPM, which would be 750 RPM at the motor, with no reduction, which is a reasonable max RPM for a stepper. In terms of force, it appears to me direct drive would also give me upwards of 500 pounds on the quill at cutting speeds, using even a large NEMA23 motor, and I can't imagine I'd need more than that.

So, question is, what size (oz-in or N-cm) motors are you guys using, and with what, if any, reduction?

Regards,
Ray L.

[mc-motorsports]

I used the Elrod conversion and it was sent and I installed it with 1:1 pullies. I used 2:1 on the table and didn't power the knee. I heard 4:1 on the knee.

[HimyKabibble]

Originally Posted by mc-motorsports I used the Elrod conversion and it was sent and I installed it with 1:1 pullies. I used 2:1 on the table and didn't power the knee. I heard 4:1 on the knee.

Do you happen to know the motor torque rating? Or rated voltage/current? Or make/model?

Regards,
Ray L.

[mc-motorsports]

supposed to be 1800 oz/in, I think not, but they are Pacific Scientific servo's 48v power supply and 20 amps using Gecko 320's.

[mc-motorsports]

And the Elrod conversion doesn't come with the servo's. Comes with everything but the servo or stepper, I think it came with a nema 23 mounting plate, but I had to make a new one because my servo's don't have Nema mounting plates, they are just round with 4 blind mounting holes in the front.

[HimyKabibble]

Originally Posted by mc-motorsports And the Elrod conversion doesn't come with the servo's. Comes with everything but the servo or stepper, I think it came with a nema 23 mounting plate, but I had to make a new one because my servo's don't have Nema mounting plates, they are just round with 4 blind mounting holes in the front.

NEMA23 suggests the intended motor torque was no more than about 600 oz-in, which seems reasonable to me.

Regards,
Ray L.