Re: [CAD_CAM_EDM_DRO] Re: Sherline Spindle Pulse disk for threading

On Sat, 10 Nov 2007 14:17:51 +0100, you wrote:

>If I understand correctly, you need quite some pulses when you want to
>do threading on the lathe.

Not true.

Only one pulse is needed by Mach3, EMC supports more and has feedback.

It depends how the controller works, Mach3 is quite capable of
producing accurate multi-start threads just using one pulse per rev. The
drawback is if the spindle slows, there's no correction for that pass.

In reality this is not a problem, inertia and the low cutting forces
involved in threading, shouldn't affect it.

Mach does this by reading the index pulse, and adjusting the feed to
suit then locks those for that pass.

I believe that in EMC, if the spindle slows, the feed slows too, if that
is correct it's not the best solution. The better option is to speed the
spindle back up.

Being able to control and set the spindle speed is essential using
either method.

BTW - I thread at 500-1200 rpm, never any less :)

Steve Blackmore
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