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View Full Version : Choosing a stepper motor



Tony Ennis
10-14-2012, 09:27 PM
I am in the process of adding a electronic QCGB to my lathe. Why? Because I can :p

Anyway, how does one size a stepper? It's an open-loop system so when I'm threading I mustn't lose any steps. I don't think (rotational) speed or acceleration is critical; I think torque is king.

Opinions?

John Stevenson
10-14-2012, 09:48 PM
Depends on what size lathe .

Tony Ennis
10-14-2012, 09:55 PM
12" A/C, the noodle-lathe of the early 20th century. So I won't be hogging off a lot of steel while cutting a 4 TPI thread ;-)

customcutter
10-14-2012, 10:12 PM
I am in the process of adding a electronic QCGB to my lathe. Why? Because I can :p

Anyway, how does one size a stepper? It's an open-loop system so when I'm threading I mustn't lose any steps. I don't think (rotational) speed or acceleration is critical; I think torque is king.

Opinions?

Found this today while doing research on my retro-fit cnc conversion.

http://www.geckodrive.com/support.html

Pretty much greek to me, but might be useful.

Good luck,
Ken

Tony Ennis
10-14-2012, 11:26 PM
Using the formula towards the bottom of the link customcutter posted, the stepper I need would be the size of a thimble.

customcutter
10-14-2012, 11:36 PM
Using the formula towards the bottom of the link customcutter posted, the stepper I need would be the size of a thimble.

I guess you'll have to take that up with "geckodrive".:D I haven't seen any thimble sized steppers.

Ken

Tony Ennis
10-14-2012, 11:44 PM
What it probably means is that I need to run the motor faster and gear it down. At 1 RPS, it takes 20 seconds to cut a 1" long 20 TPI thread. That's 3 inches of movement per minute. I'd guess that a lathe's lead screw is a very specialized application and is basically a corner-case.