double v

hi guys,
im looking at making an 8 x 4 ft plasma table, thinking of profile rails for y and z but struggling with price / availability / shipping of 3m lengths so ive been back to look at dual v again.
ive spoken to a supplier and they are talking £70/m for the rail!
im aware that the mechmate chaps do alot with profiling angle iron to make rails but given mine is a bespoke design and it wont affect any other dimensions could i not just put the angle face down so the two legs rest on the surface and the v wheel runs on the sharp corner of the material.
did i read in a post from one of the admin who has done this? has anyone else?
would it be advantageous to use stainless or aluminium for better dimensional accuracy?
also is the torchmate system of using bright steel with a plain roller bearing running top and sides worth considering?
id be greatful for any input/experiences
thanks all

For good dimensional accuracy balanced with price, I would look at cold rolled steel. Stainless (especially) and aluminum both will cost you a fortune, and CRS has them both beat for dimensional accuracy. My own linear motion system is based on cold rolled steel rails that bolt to aluminum extrusion.
http://www.speedymetals.com/information/material26.html
Ahren
www.cncrouterparts.com

Thanks for that, i invested all dy yesterday in reading the linear motion forum and i had kinda come to that conclusion, seems double v or cam followers can handle more debris and perhaps are a little more tolerant to setup than thk rails so i was planning on running cam followers on the top and side of a piece of inch square rack to replicate the hepco hg3? i forget, system and reducing the number of components to allign, bolt this to a box section frame to allow a small amount of adjustment and hopefully itll come good and i ll be several hundred £ better off.
if you were wondering the reason i can spend all day looking at the forum is i crushed my hand in our old metal gilliotine a couple of weeks ago so my fingers are welding theirselves together and i cant move them, had been looking at cnc for a bit before that, made the decision whilst waiting for surgery im gonna do it!
thanks

Look at Joe's 4x4 design he is using a double v on an angle iron for routing and he just files his to remove the debris on the angle. A lot of people have made this design and are pleased with the result http://www.factorydaily.com/forums/showth...light=Joes+4x4 (Joe's CNC 4x4 Hybrid)

Check out this new product from PBC Linear (aka Pacific Bearing)
http://ivt.pbclinear.com/IVT/integralvtechnology.asp
I saw this at a trade show and it looks perfect for a CNC gantry machine. I asked the guy working at the trade show how much the product sold for. Of course he said that he didn't know for sure because it's a new product, but he said that list price was $30-80/m, depending upon the size/shape of the profile. Most of the shapes the bolt onto aluminum frames would be in the $40-80/m range. At today's exchange rate, that should be much better than £70/m!
If you're in the UK, try their European office:
http://www.pbclinear.de/pbclinear/in...technology.htm
http://www.pbclinear.de/pbclinear/contactpbclinear.asp

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