CAD CAM EDM DRO - Yahoo Group Archive

New member, something interesting

Posted by Jon Anderson
on 1999-06-14 15:18:29 UTC
Hi, I'm new to the list, thought I'd introduce myself. I presently have
a heavily modified MAXNC and am building a CNC retrofit for my Hardinge
chucker, Omniturn style.
Using Ah-ha software at the moment on the MAX, but I'm going to be
building up a Linux box and giving that a shot.
Modifications to my MAXNC include 198 oz/in PacSci motors, Computmotor
OEM 650 drivers, motor mount plates with preloaded ball bearings to
handle thrust loads, BS&A ActiveCam nuts and 16 pitch screws, a Sherline
spindle assy and DC motor.
Somewhere down the road when I get some free time I'm going to post
drawings of all the mods, making them available at no cost.
If anyone has seen the Flashcut CNC Sherline at the Santa Clara Machine
Tool show a couple years ago, I built it.

Something I just ran across that might be of interest to some folks is a
new low cost ball screw from Thomson. They have a design contest going
and are giving out free samples for as long as they last, you can apply
at http://www.thomsoncontest.com
Just got mine today. These sure are no substitute for ground or even
precision rolled screws, but they just might have some potential for the
low end HSM CNC. Screw dia is fixed at .380 with a 16 pitch. Lengths
available are 6", 12, 18, 24, 36, and 48".
Nut has no provisions for mounting and is .75 in dia and .775 long.
There is a single return tube held in place by an injection molded cap.
Backlash specs are between .002 to .007, mine came in at .005. It should
be possible to clamp two nuts in a split block with perhaps a spring
washer to help set a light preload (obviously, before the nuts are
clamped).
Mine felt a bit rough, but was dry. A bit of grease helped a lot.
Mounting these on a Sherline would require some significant
modifications, less so for a MAXNC. They might well be a viable option
for a scratch built machine. I saw this in last months Machine Design.
The screw came out of new mfg methods developed for the automotive
industry and mention was made that they could cost as little as $5 ea.
Obviously a qty price, but it ought to give an idea where these might
sit relative to existing ball screws.

Jon

Discussion Thread

Jon Anderson 1999-06-14 15:18:29 UTC New member, something interesting Dan Mauch 1999-06-15 06:07:18 UTC Re: New member, something interesting Jon Anderson 1999-06-15 17:48:47 UTC Re: New member, something interesting