Re: using a stepper motor for spindle on a lathe

In a prior message Seiman said;
"I do not see why you want to change the spindle to stepper motor as
each one represent a completly different role."

If I can work through the logic of what is a retrofit of a manual
woodturning lathe into a CNC woodturning lathe with router option...

I basically have a setup that looks like a metal working lathe with x
and z axis, except that the axes are bolted onto the side of the
woodworking lathe which has its own spindle motor. The z axis is the
carriage that moves down the length of the lathe. The x axis is the
cross-slide that moves the tool cutting bit at right angles to the
lathe bed, but in place of the cutter I have a router mounted. The
spindle motor on the lathe is intact and can be used for high rpm
normal woodturning.

I would like to then in one instance control the rpm of the motor for
standard CNC turning with a normal cutting bit or router mounted on
the cross slide.

In the second instance, I would like to be able to mount an engraving
motor or router on the cross-slide and to do engraving, fancy
decorating etc with the spindle now controlled like a 4th axis. In
the standard mode described in the first instance, the spindle motor
turns at a controllable rpm either clockwise or counterclockwise. With
the router mounted, I will be able to rough shapes in very large
diameter logs and do spiral designs with barley twists or rope like
creations on smaller pieces. However, in the 4th axis mode, the
spindle will be stepped in either direction like an axis rather than
like a lathe spindle.

My problem is trying to understand how Mach3 will deal with these 2
setup options. It seems to me that a stepper motor could offer both
options. Perhaps the stepper motor could handle lower rpm standard
turning jobs with the router mounted and when needed the higher rpm
jobs would be done with the original spindle motor controlled
manually. I realize that there is a resolution issue with larger
diameters in the 4th axis mode that might require a significant gear
reduction.

Again, this router table is mounted to a woodturning lathe with an 8
foot by 30 inch diameter capacity. That is about the best I can do to
describe the situation. I appreciate eveyone's feedback and suggestions.

Thanks,
Keith Clark

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Seiman H <seiman_h@y...> wrote:
>

> you can have a 3 axis machine with rotary 4th axis but the spindle
still independat it usually works with Z axis in this case which do
not exists at your lathe.
>
> Seiman
>
> Keith Clark <mail@t...> wrote:
> I am wondering if I can use a stepper motor to turn the spindle of a
> lathe. I am using Mach3 to control the 2 axis router machine that
> mounts on the woodturning lathe. I will do very slow rpm work,
> shaping vessels with the router machine. It seems like Mach3 is
> capable but the docs do not specifically discuss stepper motors but
> say a step and dir controlled motor will work. Does anyone see a
> problem with this approach?
>
> Thanks,
>
> Keith Clark
>
>
>
>
>
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