Re: [CAD_CAM_EDM_DRO] question about ways vs. shafting

Rick asked:

I'm relatively new to this forum and am laying out ideas for building my own
machine (CNC mill). My first thought in designing this machine was to
support travel of all axes on steel shafting, with beaings & pillow blocks
on the necessary parts. As I look at the construction of larger CNC's, I see
that they are all constructed by means of ways (I believe this is the term
for the 'dovetailed' slide) rather than the shaft/bearing arrangement I have
just described. Which method is preferable, from an accuracy standpoint?


My two cents:
The first thing you have to ask yourself is: where you gonna get those long
hand scraped ways? I would say that for most of us, the answer is in those
Thompson/NSK roller bearing ground linear bearing/shafts. I have seen
pictures of cnc machines with the table running on the round supported
shafts. Join the competition on ebay, and you can get a pretty good deal.
I just saw some really big ones, you have to wait around and not get the
fever.

Eric