Re: New member, something interesting

I have some low cost thompson 5/8" .200 pitch rolled ballscrews on my mill
drill. They cost .98 and inch from McMaster -Carr and thre ballnuts are $18.
I replaced the .1243 balls with .1248 ball and reduced the b/l to about
.002. They work great on machines like the mill drill and the shoptask.
Dan
-----Original Message-----
From: Jon Anderson <janders@...>
To: CAD_CAM_EDM_DRO@onelist.com <CAD_CAM_EDM_DRO@onelist.com>
Date: Monday, June 14, 1999 3:20 PM
Subject: [CAD_CAM_EDM_DRO] New member, something interesting

>From: Jon Anderson <janders@...>
>
>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
>
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