The best example how a seam in the rails will not matter:

The very first guy to pick up his rails was replacing his homemade existing rails.

While installing, he put a nick in one of the new rails. He emailed me a pic and said he wanted another rail if anyone cancelled, or if we did another run.

I told him to just gently tap the nick back into shape and oil stone the spot.

He did so and although he can just barely hear the nick as a wheel rolls over it manually, to his surprise, it makes no difference at all cutting acrylic. He made a few hours of test cuts, and is completely convinced.

I'm not sure if he is a member here or not, but if he gives me permission, I'll post the repaired nick picture when I get it.

TIP: as you install or drill holes in your rails, cut a piece of old garden hose or fuel line with a lengthwise sit; and cap the rail with it.

This board is full of great ideas... I sat down and did the math on a step of 0.02 and assumed a 54inch gantry.

Now I understand why the sawdust chips and a small step would go unnoticed in the cut edge. The idea of staggering the cuts is spot on and, given the hassles of trying to handle and cut 20 foot sections of angle iron... probably not to hard to arrange.

Last night we took some time to measure out and plan the best way to run the rails in our shop. I need 2 pairs of 14 foot rails and 2 pairs of 18 foot rails for a project I am working on. I am probably going to devise a clamp, grind, move, and reclamp setup to get the job done. If I am happy with what I am getting I will run a couple hundred feet of the rails, store them, and make them available and a cut to size item. I am guesing I will have time to run my rails in early May, assuming we don't get slammed with work again.

I am pretty sure I can make the rails in a flip op with no step. In any case thank you everyone for the advice, I no longer fear "the step" in the event I have a step of a few thousandths.

I will post after I make a few rails for anyone that wants them.

Charles