RE: [CAD_CAM_EDM_DRO] 3D router Rack and Pinion or Ballscrew

Hi Diego

Ballscrews are usually the most economical choice for y and z.
I assume this is a moving gantry for x, and if so 8 ft ballscrews
have to be pretty large to avoid buckling and critical speed problems.
35mm + diameter would be typical. There are some novel ways to improve
this with traveling supports.

It is more typical in this size range to use preloaded rack and pinion.
You can make your own from the unhardened rack stock available from
Browning and others, but it is not going to live very long.
CNC grade preloaded rack systems are available at places like
http://www.andantex.com/preload.html . This is the good stuff,
but you won't like the price!

Les Watts

-----Original Message-----
From: Diego Pinto [mailto:dpm@...]
Sent: Monday, August 04, 2003 9:27 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] 3D router Rack and Pinion or Ballscrew


I'm working in a project to build a 3D Router 8x4 Ft.
I would like to have opinions about to use of ballscrews or gear racks for
main axes.
And maybe the best source for Racks and pinions.
Regards.
Diego