Re: [CAD_CAM_EDM_DRO] How do I add CNC to a lathe?

On Thu, 24 Apr 2003 16:51:09 -0000, you wrote:

>OK I'm hooked. I just finished the hardware end of converting my
>Bridgeport to CNC and now I'm ready to tackle my lathe. Problem is,
>I'm clueless from a mechanical standpoint (I'm OK now with stepper
>electronics and control circuits - I think) where to begin.
>
>I have a Logan lathe circa 1943. The max swing from the center of
>the chuck is 5.5" (does that make it an 11" lathe?).

In Europe, no, it stays 5.5; in the US, yes, it's an 11 inch lathe...

>The gears to
>make various threads have to be hand changed on this model. It's
>belt driven.

Ok, stepper "phase lock loop" methods are possible using the spindle.

> It does have motor driven feed on the carrage and the
>cross feed.

If you want to keep the motor driven feed and keep the thing manual as
well as CNC, then I'd consider another drive that will tie into the
existing carriage and crossfeed drives. You would throw a lever to
engage the steppers, and that would not engage unless the manual drive
were disengaged.... And that would also lock out the manual drive...
could be as simple as a few pins...

>Any guidance on where/how the motors should be mounted,
>as well as any other mechanical things to look for would be
>appreciated. Any place I can look for diagrams? Is this project
>even worth it or should I leave well enough alone?

The Carriage feed motor can be mounted off the tailstock end, but you
will have to take care that the carriage can't be driven from the
lathe spindle while the threading gears are engaged.

Mechanically, I'd be tempted to allow manual operation as well as CNC,
and I'd also be tempted to use as many of the existing mounting holes
as possible.

Harvey

>
>Thanks and regards,
>Jeff
>
>
>
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