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Panovak Sun 05 January 2020 09:37

Using used linear rails
Hi guys,
I have an opportunity to buy used square linear rails. They are about 30mm. Two are 8'3" and two are 6'. These are very beefy rails.
These are used and I was told they were worn about 0.01". I'm not sure in what direction or how much of the rails is this worn.
My question is: how bad is 0.01"? Is the effect more profound than just throwing off accuracy 0.01"?
My other concern is I want to build a 4x8 machine. So I would have to cut and butt these linear rails. Is this going to be a big challenge?
He is asking very little for these.
Thanks for you help

swatkins Sun 05 January 2020 10:34

For a 4 x 8 machine your x rails will be about 123 inches long.

0.01 is less than it seems when written the more common way 0.010. Your machine will have at least a 10 thousandth of an inch built in error before you even start. If the error is low on one rail and high on the other it could be 20 thousandth.

In my world 0.010 is huge. It may not matter in your world. It all depends on what you are making and how picky you are about the finished product.

Personally it would bug the hell out of me knowing the machine had an error that I could have eliminated.

Panovak Sun 05 January 2020 16:31

Ok. I think I'll pass on getting these then. He actually said I could have them for free but i saw them in person today and they were pretty beat up.

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