Hello all,

I'm looking to build a new CNC/manual mill. I have a ~1,000 pound (450 kg) table that has been ground flat, with a surface area of 42" x 36" x 1" thick (106 x 91 x 2.5cm).

The build criteria is simple: be as rigid as possible, within limits.

To that end, I'm leaning towards a fixed bridge design using heavy wall square tubing, 35 - 45mm guide rails, and as big a diameter ballscrew as I can practically fit under the axes.

Here's a scratch design I've been noodling with while contemplating ideas. This is not a final design and I'm not really looking for feedback on it, just to serve as a conversation starter:



Soooo... if you were building a mill from scratch that can hog through steel and not break a sweat (or end mills), what would you design? Is a fixed gantry a better design (within its compromises) than column? The commercial machines I've seen on YouTube easily cutting steel have all been column types... hmmm.

Thanks!
JR

PS: good to be back. Looks like I've been bitten by the CNC bug again ;-)