Thanks Barry, lots of equations to steal, Umm i mean use.....:whistling: thats a good idea to have them on one sheet and then linked to graphs. I like it. It wouldn't take to much to add the resonant and harmonic frequencies as well.

I fed those numbers into my Gantry Spreadsheet (using tube profile with OD 16 and ID 0, length 900mm and load 250N) and got the same values for second moment of area and vertical deflection.
Thats a relief, I'm good at finding fault with other peoples work but then make stupid mistakes in my own :whistling:

just a couple of points I'm unsure of.... It states simply supported for the vertical deflection but fixed for the torsion calcs. Are they separate calcs or are you assuming that the hinge joint can resist axial rotation?

Also I have been after an equation for the torsion constant (k) for a while but I always understood that it is pain to calculate for anything other than a cylinder. The program I have gave a different answer than you for the 80 x 80 x 3mm box section. I make it 1.37 e6!! [1370000] (not had chance to fire up the FEA yet so it might be the free programs I'm using, but it has always been correct before).

I only ask because I've been trying to think of a way to do what you have done for a while now but have been stuck at the torsion bit and have to resort to individual section checking of FEA. I think the only real solution is to create (or find) a data base of the most used sections (inc extruded t slot) and put them on a pick list in excel