Joining Lengths of linear rail together..

[hotponyshoes]

Hi all!

For the x axis on a plasma table I would like a 2 meter travel.

I am looking at linear rail and bearings (used) for the carriage.

It seems to work out cheeper to buy 2 x 1m lengths than 1 x 2m length and the 1m's are a LOT easier to come accross!

What woulf be the best way of 'joining' two bits together?

I will be most likly to use the 25mm wide rail and so far I have come up with the following:

Get a 2m length of 50mm dia alloy bar (solid) and run a flat along it with a 25mm milling cutter (or maybe sink the 'grrove' down a couple of mm), drill and tap holes and bolt both lengths down to it.

This should line them up nicely I would think!

Any other ideas / suggestions?

I have thought about trying to tig weld the rails together and I also wondered if just bolting them to the frame (angle iron) would be good enough.

Also, while I am going :-) do you guys use all the holes in the rails to fix them down or would just using one at each end help the rail stay strighter?
I would have tohught that (unless whatever you were fixing to was ground dead flat) you would deflect the rail. Would it be best to put a bolt only at each end with a washer between the rail and the mounting surface and 'float' the rail? This is assuming the rail will take the weight of the gantry without deflecting?

Thanks!

[snowshovelbmx]

the rail needs to be bolted to a machined surface with all the bolt holes securing the rail for best results. I would not think that the rail would be sufficient support without deflection.