Re: [CAD_CAM_EDM_DRO] Re: X-Y Table, Rotary Table for CNC INFO

Hi Les:
Sounds a bit like a screw that has been unrolled from around its
shaft!!! : )
Best way for this approach might be a pair of wedges mounted on linear ways
tipped up at an angle.
Kind of like a ballscrew unrolled from around its shaft.
Do you think four linear ways and one ballscrew would be cheaper than 4
ballscrews, nuts pulleys and timing belt?
What about rolling it uphill on wheels (bearings)?
This thought experiment is starting to show some promise!!
Cheers

Marcus

----- Original Message -----
From: "Les Watts" <leswatts@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Thursday, January 16, 2003 2:11 PM
Subject: Re: [CAD_CAM_EDM_DRO] Re: X-Y Table, Rotary Table for CNC INFO


> Dave,
>
> You're right about stubby ballscrews being very expensive.
>
> Most of the real cost the nut, end machining, and end bearings.
>
> So a 5" ballscrew might cost almost as much as a 5 foot one!
>
> You mentioned punch dies.
>
> What if you used 3 or 4 sliding bearing columns like many
> die sets but performed z axis with 3 or 4 corresponding
> sliding wedges (actually linear cams)? The wedges would
> translate a single horizontal motion into an accurate
> "parallelogram" type vertical motion. Perhaps using cam
> follower bearings with strong spring preload. I have seen
> some machines made this way.
>
> Just trying to think of how to get the cost out of something
> that you could just bolt on and go... or optionally bolt
> on a simple fixed spindle structure later.
>
> Les
>
> Leslie Watts
> L M Watts Furniture
> Tiger, Georgia USA
> http://www.alltel.net/~leswatts/wattsfurniturewp.html
> engineering page:
> http://www.alltel.net/~leswatts/shop.html
> Surplus cnc for sale:
> http://www.alltel.net/~leswatts/forsale.html
> ----- Original Message -----
> From: <david_mucha@...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Thursday, January 16, 2003 8:36 AM
> Subject: [CAD_CAM_EDM_DRO] Re: X-Y Table, Rotary Table for CNC INFO
>
>
> > Hi Les,
> >
> > I think a simple adapter on the fine feed of most mills would be very
> > easy. just mating gears with a slip connector, like a reverse ring
> > gear. I think there are similar units for shaft alignment.
> >
> > remove for easy manual. all it would need is one mount for torque
> > and then just software home setting.
> >
> > Seems much easier than a rising table.
> >
> > My punch dies with ball screws are EXPENSIVE in short strokes. I
> > think the ridigity would make a power Z better tan a power table.
> >
> > imho.
> >
> > Dave
> >
> >
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Les Watts" <leswatts@a...>
> > wrote:
> > > Hi Marcus
> > > Hmmm I guess 4 short ballscrews with timing belt or something.
> > > Kind of like my wood planer.
> > >
> > > It would have to be rigid, but it might be so small that it would
> > not
> > > be too heavy.
> > >
> > > Just daydreaming really... people often ask if I can design a
> > > small cnc with good accuracy for an arbitrarily low price...
> > > but the price usually turns out high. Manufacturing even small
> > > machine tools in the US is a pretty rough proposition.... consider
> > > Bridgeport, South Bend, et al. But one can do it for a hobby
> > > with no problems! As a business I only build machine tools
> > > for internal use and that has worked out ok. Of course I do
> > > design some production machine tool components, but
> > > the development cost is pretty high for my customers.
> > >
> > > Les
> > >
> > > Leslie Watts
> > > L M Watts Furniture
> > > Tiger, Georgia USA
> > > http://www.alltel.net/~leswatts/wattsfurniturewp.html
> > > engineering page:
> > > http://www.alltel.net/~leswatts/shop.html
> > > Surplus cnc for sale:
> > > http://www.alltel.net/~leswatts/forsale.html
> > > ----- Original Message -----
> > > From: "Marcus & Eva" <implmex@a...>
> > > To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> > > Sent: Wednesday, January 15, 2003 11:10 PM
> > > Subject: Re: [CAD_CAM_EDM_DRO] X-Y Table, Rotary Table for CNC INFO
> > >
> > >
> > > > Hi Les:
> > > > Were you thinking of a four poster bed type of setup with a
> > central
> > > > screw?
> > > > Or maybe four timed screws with encoders or steppers slaved
> > together?
> > > > I suppose you could chain drive them or belt drive them from one
> > stepper
> > > > too.
> > > > That could work pretty well I think, if you used good hunky
> > frictionless
> > > die
> > > > bushings and pins.
> > > > I'm thinking of the kind that have sleeves with balls in them;
> > the ones
> > > > that are used for big punch dies.
> > > > You could make the base wide enough that the pins hang over the
> > edges of
> > > the
> > > > mill table as they come through the base plate.
> > > > That way you wouldn't lose too much height under the spindle nose.
> > > > Gonna be a pretty heavy accessory unless you make the base out of
> > > aluminum.
> > > > Cheers
> > > >
> > > > Marcus
> > > >
> >
> >
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> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto:
aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if
you have trouble.
> http://www.metalworking.com/news_servers.html
>
> 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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