Re: Motor Size estimate?

>
> Just for ref, I ran plain screws on my lathe for a while during the
> conversion phase ... I used various combos of manual and CNC control
> throughout this while making the parts to hang the screws. I was able to
> run the long feed with 8 TPI and direct drive, using stepper rated at 450
> oz-in at I think 3.5A; I am actually only giving them 2.8A. I'm sure your
> carriage is a lot heavier though and a 13" lathe is going to take more
> force at the cutting edge. You can probably get by fine with 600 oz-in and
> ball screw on long feed, esp if you drive with a belt reduction. In that
> regard, I pushed the HS out of line on my lathe the other day using the 450
> motor, 5:1 gearing, a 5 mm pitch b-screw, and a wrong command. The HS sits
> on flat ways and is clamped down by two 10mm bolts. It's never moved under
> cutting forces and I've jammed it down to stalled before plenty of times.
> This didn't seem to faze the screw, nut, stepper or drive, so I'd say 450
> is fine for cross feed.

Hmm, Supertech has some NEMA34's rated 665-470 oz/in (bi/unipolar) for
$219, which is within my budget. They have a double stack one for
eighty bucks more, but I'm not sure it would fit under the feedscrew
and in front of the apron the way the single stack one probably would.
I may have to consider getting one.

Chris


--
Christopher C. Stratton, stratton@...
Engineer, Instrument Maker & Horn Player
(978)538-5179 work, (617)492-3358 home
30 Griswold Street Cambridge, MA 02138
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