Hey guys, I've been visiting this site for awhile and have started planning my own CNC. First off thanks to everyone who comments and shares their wisdom/knowledge with all of us just beginning this obsession. The wealth of knowledge is a little overwhelming but very appreciated.
Ok now down to business. I'm planning on constructing the bed with a usable area of about 24" x 36". I've been saving some 30mm linear bearings (open style) for the y-axis and a few 16mm bushings/bearings for the z. I wanted to use supported rail but don't want to spend $$$ for the manufacturers rails. I was thinking about some drill rod, or stainless steel shaft. It needs to be tight tolerances...any ideas/suggestions? Know any good websites to order from?
Also should i think about using thick wall tubing instead and make some supported rails myself, i don't have a milling machine or anything, I'm a furniture maker so it needs to be fairly painless for me.
Thanks for any comments, I'm excited to finally start seriously planning.

Look at Joes kit in the JoesCNC subforum.

You may want to check out www.buildyouridea.com. He made some supports for rails with a lost foam casting process. I followed his work to design my linear bearings, only wish I would have stuck with the supported shafts. My cnc router is almost done and I'm already planning a way to change the unsupported x axis.

bobf,
I've definitely gone through joes build, it's been awhile but I think he still uses drill rod as the rail system and i think he orders it from Enco. Problem is that they don't sell much drill rod in metric, particularly 30mm. It is a good idea, I just need some leads on where to get some the size i need. I tried searching the internet for over 2 days with no luck. Metric is rough to find that large.

Texas,
I have also seen that build as well, great work on his part. That was my other idea, using tubing instead of rod, that way i could make a T-supported railing that was easier to attach, less expensive but offered more rigidity than an unsupported 36" rail.
Has anyone tried using found rod/tubing with THK, NB, etc high precision linear bearings? Will it work or will i be disappointed with a sloppy/too tight fit from the tolerances?
Thanks for the replies

You may try McmasterCarr for the metric rods, They are a little pricey but they seem to have everything.

Praire Dogn,
Look at post 92 in this thread for an alternative to round tails.
http://www.cnczone.com/forums/showthread.php?t=34044&page=8