Formed steel cnc router

[AdCNC]

As regards to mounting the bearing rails on the C section you will struggle to get them running level with each other unless you weld the whole lot together and skim the surfaces, but not many people have access to that sort of equipment. but by doing that you are reducing the thickness so welding a pad on first and machining that down and also incorporating a datum edge for one of the rails to but up against would be a good idea.

[sbams]

I do plan on skimming the rail surfaces but not all to getter. My plan is to fome the C section weld in the gussets then machine each rail separately, then weld the whole thing together. I have a 2" thick surface ground welding table I can clamp it to while welding. I'm hoping this will keep it straight enough. I did not think about the pads which I like so I added 3/16 pads under the rails for machining. Thank you :)

[andrewbond]

If the steel is free ... or at least no cost ;) I'd say try and make the c- channels into a box somehow. Also maybe put some forms on the ends of the gantry sides for stiffness, have a look at ShopBotTools CNC Routers they use formed steel for the gantry sides. of probably a similar thickness.

[AdCNC]

No matter how you weld it buddy, it will still warp. you may control the amount a bit by clamping to a table but it will still twist. hence you need to perhaps weld on pads where the box or parts mate and machine the surfaces then bolt them together, this way you have a small degree of adjustment and do away with warpage.