Erik Christiansen wrote: >>> There's then room to fit a vertical ballscrew, clamped externally >>> to the quill nose. >> No, I would not do that. It will be very hard to make this rigid. A >> friend has a benchtop mill with that rig, and it is very flexible. >> That's why I did it from the stop ring bolt hole. > > Hmmm, my quill lacks a stop ring. There's just the last 2" length > widening from 3.5" to 3.75", then the INT30 socket and dogs below that. > I was thinking of boring out a piece of 1" thick steel plate to 3.75", > to make the clamp. The rest seems to mimic what you've aleady done, just > at the side, because that's closer to the quill, once the pinion drive > is removed. > > The quill nose can best be seen after scrolling down to the second lot of > pictures at: https://www.machineryhouse.com.au/Products?stockCode=M161 >
My shoptask (cheap chinese lathe-mill-drill) had horrible backlash in the rack and pinion quill drive. There was lash in the rack-pinion itself, lash in the dog clutch that connected the pinion to a worm gear (disengaged for manual feed), lash in the worm gear, and axial play in the worm mounting. The total was about 0.050 to 0.060 inches. I found a surplus ballscrew and cooked up a rotating nut assembly around it. It is attached at the bottom of the quill, with a bracket made of 1/2" thick steel plate that clamps around a tapered ring on the quill. I completely removed the entire original assembly: pinion, clutch, worm gear, and worm are all gone. An external view is in center of the third pic on this page (click to enlarge the pic): http://jmkasunich.com/cgi-bin/blosxom/shoptask/initial-teardown-12-16-06.html A sectioned drawing is on this page: http://jmkasunich.com/cgi-bin/blosxom/shoptask/Z-axis-12-16-06.html > This is just like software development. Time spent working through the > wrinkles before you cut [code|metal] pays off one hundredfold. > Exactly - it took a quite a bit of thinking and drawing to get that designed. I wanted to keep the screw centerline as close as possible to the quill centerline, but had to avoid the spindle drive pulley and various other obstacles. Rotating the nut helps a lot, at least in my case. Short ballscrews show up regularly on ebay, and aren't terribly expensive. Good luck, John Kasunich ------------------------------------------------------------------------------ OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
