Premature Ebay-ulation?!? (single Z axis linear rail)

[braidmd]

I've been debating linear mechanisms for the Z-axis on the machine I'm building (finally!!!). I've been leaning towards linear rods and bearings from VXB. But the cost, though reasonable, has been holding me back. And I'd really like to have supported rails... which ties into the issue of cost. After reading another thread, I've decided to head into a different direction...

I found some IKO rails on Ebay for a price far below that for the VXB package (photo attached). They are "IKO Linear rails 24" by 16mm high 40mm LWLF42B". Just bought them minutes ago... I must admit that I don't know much about this style of rail, as far as the strengths and load limits. But I thought that I'd take a chance. The rails are wide (40mm), the bearings are larger than the light-duty stuff I've seen... and I picked them up for $87 with shipping. Anyhoo, my plan is to use the two bearings on one rail, which I'll have to trim a bit to fit my design. No worries there...

So do you think this setup will work? Or will I have to go shopping for another set of bearings and run the rails as a pair?

Mike

[ger21]

It of course depends a little on how well it's mounted, and what your hanging from it, but assuming a standard handheld router as the spindle, it should be fine. Even small 15mm rails can handle several hundred pounds of force.

[oeffner]

should work but usually use 4 "cars " to keep every thing more rigid and aligned. I have passed on many Ebay rails because there were only 1 car per rail and additional cars from the manufacture cost a bunch.

[braidmd]

The rails are here! Actually, they had arrived on Friday. They look good... used, but good. The bearing blocks (or cars?) roll smoothly and feel tight: No play any-which-way. Now I just need to redesign the Z carriage so I can mount them properly...

Oeffner - I too think (or thought) the same way... it seems logical to have two rails and four bearing blocks for stable motion. But I have been inspired by Ger21's latest, greatest design thread. So I thought that I'd take a chance with his concept.

http://www.cnczone.com/forums/showthread.php?t=45844

If Ger's configuration holds up... or my interpretation of it, at least... then one THK-style rail with two blocks might prove to be a more affordable way to integrate precision-components into the world of DIY. If it doesn't work, then I'll just blame Gerry.

Nah, I wouldn't even think about it...

[ger21]

As long as the rail is mounted securely, you shouldn't have any problems. We have 10HP spindles mounted with single 25mm rails on our machine at work.