Re: [CAD_CAM_EDM_DRO] Linear rail & ball screw size suggestions

Jay,

I built a small router about the same size as you are talking
about, and used THK SR15 rails and blocks. The 15 is the
width in MM of the rails. They can usually be had for a
reasonable amount on ebay in the size you are looking for.
Mine has about 18" travel in both the X and Y axis and 6" in the
Z axis. They work really nice for a small router. Don't get the
THK RSR type minature rails as they are kind of wimpy. SR 15
or HSR 15 or greater should work well. You can see a picture
of my machine in the photo section in the "Bill's Router" folder.
http://photos.groups.yahoo.com/group/cad_cam_edm_dro/lst?&.dir=/Bill%27s+Rou
ter&.src=gr&.view=t

Also, since the size is somewhat small, you may wish to make
a moving table instead of a moving gantry. Much simpler to
implement without worying about the gantry racking or driving
it from both sides

I used 3/4" ballscrews and servo motors because thats what I
got surplus for $30.00. I'm sure the inexpensive McMaster Carr
5/8" would have worked just as well. I have a couple of friends
who have built nice tables using leadscrews and the plastic anti-
backlash nuts without any problems. If you don't have motors and
drives yet I would strongly recommend servos over steppers. I
had steppers on this machine before, and the performance is
so much better with the servo motors.

I built mine out of 80/20 aluminum extrusion, expensive stuff, but
easy to work with. I'm building a larger machine now.

Bill

----- Original Message -----
From: "J.Critchfield" <js3mc@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Wednesday, April 10, 2002 7:21 PM
Subject: Re: [CAD_CAM_EDM_DRO] Linear rail & ball screw size suggestions


> I appreciate the feed back on the Roto-zip. I share your concern about the
> plastic housing. My carpenters use them or I should say abuse them on a
> daily basis and they have held up well so I'm pretty sure there is enough
> power for what I need. I have one to take apart and see it if a more
robust
> housing could be made.
>
> Now does anyone have any other feedback on linear components and
ballscrews?
>
> Thanks,
>
> Jay
>