3-Axis CNC Mill Project

[boldford]

Wouldn't the frame be stiffer with a few diagonal members added?

[Hobgoblin]

Wouldn't the frame be stiffer with a few diagonal members added?

No, you must be unfamiliar with my materials, the stuff im using is stiff and strong enough for what i need it for.

//EDIT - (Two months later to the day) Oh how wrong and misguided i was, keep reading and you'll see progress from this day forth hehe.

[JAZZCNC]

No, you must be unfamiliar with my materials, the stuff im using is stiff and strong enough for what i need it for.

Think you'll find he's correct and Yes I am familiar with your materials.!!

What your not accounting for is the Mass of the gantry and it's inertia.?
It doesn't so much matter what your cutting the Mass of the gantry will have a big affect and actually if soft material then usually means high feed rates which affectively makes the gantry a very heavy thing indeed which will put more stress upon the frame trying to twist it and push it out of shape.!! . . . At this height and narrow width and also from the look of your doodle showing the high gantry sides I wouldn't be one bit surprised if it didn't try to tip it over when rapiding at even mild speeds.? . . . I would certainly think about bolting it down or have plenty of ballast low down.!!

For the little extra cost it would be well worth it to brace the frame now rather than find out it's twisting and moving around while cutting then have to do it later and go thru all the shimming and setting up again.!!