"Richard J Kinch" wrote in message
. ..
Pete C. writes:

Steppers produce a lot more torque than you
apparently think, with even small 23 size units producing over 600
oz-in. Coupled with any reasonable leadscrew / ballscrew pitch that
translates into plenty of force for smaller machines.

You confuse torque and linear force with power. Yes, you can gear up or
down to any torque you like. But power is what counts: force times
distance
per time, which is to say the capacity to complete useful work when
integrated over time.

Steppers are inherently weak. Their dismal torque ratings are only
delivered at very slow speeds, which is to say, at limited power. Some
motion control tasks require little power, and steppers will do, but for
metalworking, you need power: the ability to accelerate quickly and push
rapidly against resistance.

Perhaps when hogging out with larger cutters, but for detail work with tiny
cutters they generate more than enough speed and "force." The trick is to
find an optimum feed, depth of cut, approach, and width of pass to get
fairly decent material removal without breaking cutters. An 1/8" or larger
cutter can crash the machine, but a 380oz stepper has enough force to break
anything smaller in a heart beat when you go for too much. For some of what
I am doing an 1/8 cutter is very large. The only time I really wish for
more force and bigger cutters is when making larger parts to modify the
machine itself like different spindle mounts or motor mounts.

When I get the Hurco going it will get to do all those big parts.