Re: [CAD_CAM_EDM_DRO] Building a small 4th axis

At 11:59 04/06/2003 -0700, you wrote:

>Hi Tony,
>
>Yes! I recall seeing that photo before. Certainly works! That I can
>do in the mill, with the CNC rotary table.
>
>Does sound like the gear head Vextra's would be slow to cut a thread,
>but I'm in no hurry. Another thought was to drive the 90V Sherline
>motor with a Gecko G340 servo drive. Even at lower voltages, that could
>be useful.

Now that is an interesting thought!

Regards,
Tony

>Alan KM6VV
>
>
>Tony Jeffree wrote:
> >
> > At 11:15 04/06/2003 -0700, you wrote:
> > >Not exactly the same thread, but I like these "symbiotic" ideas! A few
> > >days ago I saw a Sherline rotary table w/stepper being used to drive the
> > >Sherline spindle on a lathe for threading (and what not). Probably on
> > >Bryan's web site. Seems to me that a gearhead stepper motor (some
> > >Vextra's I picked up come to mind) could be used quite easily the same
> > >way. This would allow any CNC controller program to turn the spindle in
> > >direct ratio to the lead screw, which is what's wanted. The other way
> > >is to add an encoder to the spindle, "Sync" and drive a leadscrew off of
> > >that via software.
> >
> > Hi Alan -
> >
> > There was a series of articles a few years back in Model Engineers'
> > Workshop magazine, describing a CNC-ed Taig lathe. The guy had indeed
> > managed to do threading by stepper-driving the headstock via a reduction
> > drive, and driving the saddle traverse & headstock motors at appropriate
> > rates to generate the right lead per rev. Problem he described was that,
> > because the power available from the stepper on the headstock was
> > significantly lower than a conventional spindle motor, he had to use low
> > speeds (to maximise the stepper torque) & hence cutting any significant
> > thread length was interminably slow. Perfectly possible though.
> >
> > I have done a similar thing on my mill - using a rotary axis to rotatre the
> > part to be threaded, and a 60-degree V-tip engravibg cutter to cut the
> > threads. See the second-from-last photo on this page:
> >
> > http://www.jeffree.co.uk/Pages/divheadmk2.html
> >
> > Took a while, but generated a great thread!
> >
> > Regards,
> > Tony
> >
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>OFF Topic POSTS: General Machining
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>reach it if you have trouble.
>http://www.metalworking.com/news_servers.html
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>http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
>sister site to the CCED group, as many of the same members are there, for
>OT subjects, that are not allowed on the CCED list.
>
>NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING
>THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
>bill
>List Mom
>List Owner
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>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

Regards,
Tony