Re: [CAD_CAM_EDM_DRO] 85oz/inch Japan Servo Stepper Motors

> I got a really good deal on some Japan Servo Motors. They are a Nema
> 23 rated at 85oz/in.
> How big of lead screw should I consider going with these motors and
> what size guide rods for ways?
> Really budget conscious here. Any info would be great. Has anyone
> else used comparable motors?

Brett,

It all depends on what kind of machine you are trying to build.
Generally you size your ways and leadscrew based on the loads you
expect to encounter and to some extent the speed. Then you size your
motors and timing-belt reduction (if any) based on the load, speed,
and screw lead.

To take one example, the sherline lathe and mill are often equiped
with motors this size. They have dovetail slideways in the range of
1.5 to 3 inches wide or so and 1/4 to 3/8" diameter 20 tpi screws,
usually run direct drive. They also have a maximum travel of only a
few inches in many cases. Run with an 85 oz*in motor, they may move
at 10-20 inches per minute.

Say instead of a small machine tool you were building a large but
light duty gantry router with a work envelope measured in feet. You
would need much larger screws for that - at least the 5/8" rolled
ballscrews. And you would probably need some reduction to drive it
with these relatively small motors, which means it would move very
slowly. If you used round rails, their diameter would have to be
determined by the expected forces and the distance between supports
(ie, rod supported only at the ends, or rod sitting on top of
full-length support rail).

Chris

--
Christopher C. Stratton, stratton@...
Instrument Maker, Horn Player & Engineer
22 Adrian Street, Somerville, MA 02143
http://www.mdc.net/~stratton
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