Outrageous CNC Machine - 5axis - 2mins of amazingness

[routercnc]

PPPS Why are RSJs not used where long box section flexes/twists and 15-20mm plate is too expensive?

Hi Williamturner1,

RSJs are actually no better in bending than a similar sized box section, are are also very much worse in torsion. Plate, even thick plate, can also be poor because you need material away from the neutral axis for stiffness i.e. wide hollow sections.
See the 'gantry stiffness' spreadsheet in post#2:
http://www.mycncuk.com/forums/showth...ign-principles-.-.-.

If you have a box section which is bending or twisting too much you either to add additional supports, or need to increase the section size. Sorry, RSJs are not a panacea.

As for your new machine, sounds like you a have a nice list of bits - but naughty you for hiding them :whistling: ! Start up a new post with some sketches, scanned drawings, whatever you have, and we'll make some comments. It's worth adding what you want the machine to do.