First Build-Steel Gantry CNC - Comments on design wanted

[njhussey]

A few more questions as im not so familiar with aluminium
-Do I have to use Aluminium Tooling plate, or would 20mm 5083 Aluminium be OK? (Plate used in ship building industry)
-Does using Alu plate still require additional bracing of the Z axis, or is this much stiffer in it self?

Tooling plate is best as it is ground flat so you don't have to do as much machining. With standard Aluminium plate it's not quite flat so wound need machining so the rails were exactly level with eachother. No Aluminium plate if it's 20mm thick wouldn't need additional bracing, there are loads of examples on this forum of machines with exactly this. I wouldn't get hung up on weight as I've got a 40mm thick front plate hanging off my Z axis and it's no bother at all. As I said somewhere else when I was putting my 20mm thick aluminium plate on the base I had my machine vertical and just for a laugh stood on the gantry and turned the X axis ballscrew (both linked with a belt) pulley with a thumb and two fingers and easily lifted my weight (19.5 stone) so don't get too hung up on weight, there's a huge mechanical advantage when using ballscrews!!

I will have to work a bit more on the design of the Z axis, and I guess finally make a descision on Steel or Alu.

Looking forward to seeing your new design....