Tig weld rack and pinion to cnc plasma frame?

[warwick]

Not sure that this will be a good idea. How are you going to implement it?

hi clive, i'll be extending the gantry outpast the side of the machine so i can carve gas cylinders

16mm supported rails will handle 80mm box section easily so wouldn't be bothered there.

Dump the link pallet idea as it will only cause you grief. No point spoiling machine for little extra piece of box section costs.
80mm or 100mm box with with few well placed braces will be fine for plasma machine.
Regards the overhang then if you talking about using for Rotary type axis hanging off the side then yes no problem.

But if your talking about actually engraving on separate table kind of thing then I'd say don't waste your time and just build another machine because engraver and plasma are two very different animals.
Engraving machine needs to be far stiffer and accurate to work well and R&P just isn't going to cut if any real fine engraving type work is to be done.

i'd like to be able to cut gas cylinder up,so i thought a couple of pillow block bearing supporting a shaft and then geared down so i can drive it with a stepper motor (in very simple terms).........you say 80x80 or 100x100 box will be ok..do you mean mild steel box or alloy? im more comfortable working in steel ..the link pallet racking idea was just because i had a pallet of the stuff knocking around BUT as youve said it will just devalue the integrety of the machine ...many thanks....