Re: [CAD_CAM_EDM_DRO] I need controllers and steppers

> MY experience is with totally home-brew machinery, and I would counsel that
> you consider the new Superior Electric KML-062 series (exactly which one, I
> leave to you and/or others who "know"). And, for drivers, the Gecko 210.
> Cobble your own unregulated power-supply, if you can DO that. Else, read
> this group, and someone will instruct you how, or where you can buy one.

I have an old light machine sherline lathe with puny high inductance
steppers and a low performance L/R drive. I haven't used it very much,
but I think that in this underpowered condition it can probably take
any cut the sherline 'iron' (well, aluminum) is designed for. Yes, you
can overpower it by twisting the handwheels, but the sherline is not designed
for high cutting force.

Where the undersized steppers and low performace drive really hurt is
on rapids (ie, fast positioning moves when not cutting). In a word,
they aren't. It generally stalls at around 6 inches per minute, and I
typically run it no faster than 4 ipm. If you are trying to make
a lot of parts on the machine, this will cost you time/money.

That said, any modern low-inductance 150 oz-in NEMA-23 mount stepper
motor should be good. Sometimes you can get slightly lower
performance ones cheaper (I got some roughly 100 oz inchers at
www.herbach.com for $20, but that was two years ago) and these can be
a fine way to get started as they are all interchangeable if they are
the same NEMA size.

As for drives, there are two popular choices: the "2 amp bipolar
chopper" products based around the L297/L298 chips. These cannot,
unfortunatley, put rated current through the better low inductance
(ie, low resistance, high current) 150 oz-in motors, but they do okay
on the slightly smaller ones. Then there is the G210 from
www.geckodrive.com which goes for $129 apiece and can run bridgeports
with motors that weigh more than the entire sherline lathe.

If I were starting over, I'd buy the G210's as they are a good
investment, and shop around for some cheap surplus motors, which could
be replaced later if necessary.

If you are near Boston you are welcome to come try the wimpy-motor
sherline for reference... Or send a scrap of whatever stainless you
want to try to cut (assuming a test with an hss cutter is meaningful).

Chris