Screen Door bearings for Homebrew CNC

[macmiester]

I'm in the process of getting materials together to build my first CNC router. This first machine is mostly proof of concept and a learning experience. As such, I'm putting it together from anything I can find laying around my gararge.

Okay, here's the question. I have a box of brass bearings that appear to be for sliding screen doors. They are about an inch in diameter and have a half circle bearing surface and no detectable play. I'm thinking I could put them on the top and bottom of a rail with a matching bearing profile. Has anyone tried this? Think it'll work?

Thanks,

[coherent]

Originally Posted by macmiester Has anyone tried this? Think it'll work? ,

I'm sure someone has, hopefully they will respond. I was at a surplus hardware store and came across some of the same bearings in the original packages for pennies each so bought about 20 of them. I considered the same setup as you mentioned but never go around to trying it and went another route. I don't see why they wouldn't work. As long as you build in adjustment points for the bearings. The trick is finding or making a suitable "rail" for them to ride on that's straight and true. Then just make sure everything is parallel! Keep us posted if you try, as I'm sure there are others who are interested in the possibilities.
-marc

[sol]

The bearings have too much slop for a CNC application.
I've tried them for proof of concept and returned to the tried and true skate bearings or equivalent.
The patio door bearings are still on a mat-board cutter that I made, but only on the X axis which is locked into position while the cut is done along the Y (which uses skate bearings on conduit).
Cold-rolled-round rod is used as the track for the door bearings...1/4" I think?
Anyway from my experience they are not worth the trouble.
They did look like a good idea though didn't they

A cheap and dirty table I made...
http://solsylva.com/cnc/cnchome.html

[macmiester]

Thanks for the feedback. I don't know if this will make any difference, but I went to Ace hardware today and figured out that the bearings are for sliding GLASS doors, not screens. The ones for screens are a bigger diameter, thinner, and do have lots of play. I think I'll hack up a rail using rod like you mentioned on some sort of support, take a pic and put it up here for critique...

[sol]

My old Sears radial arm saw uses bearings like these and its play is negligible. So if the bearings are durable enough they should work.
Good luck!