Re: Is this too nuts to consider ?

Interesting,

But wouldn't it be a "ratchet" movement? Only one pulse per rev of the
spindle? I'd think you'd need an encoder on the spindle. ...So if you
cutting a 3/16" x 16 thread, you'd only get 22.5 degree "approximations"
of a circle (it would look more like a 16-sided rod?). Must be tricks
to approximate or interpolate between the pulses from the sensor. I
guess if you could determine the approximate spindle speed...

Alan KM6VV

Area51tats@... wrote:

>
> What you are talking about has allready been done. Connecting a stepper or
> servo to the lead screw and then placing a small magnet on the spindle
> pulley so that it passes by a sensor so that the controller always knows what
> the relationship between spindle and leadscrew is. It is called "the Frog"
> <A HREF="http://www.miclog.com/frog/">Frog - low cost X-axis CNC for micro
> lathes</A>
>
> I am not connected nor do I own this unit. Yet...
>
> Gerald
> Iowa