Originally Posted by Geof  Yes but the old fogies guess was pretty close.
mxtras how about a torsional load of about 100 lb ft applied at the center, the cutter forces do not act directly on the tube. I guess this will prove to be okay also. |
At about what distance would the forces be acting? Are you asking for 100 pounds of torsion about the center of the tube? I would guess that the torsional forces would be produced by the cutting forces at the tool which might be a few inches from the center of the tube.
With a 4"X2"X.120 tube standing vertically (4" in the Z axis) and a 100 pound force acting about 4" from the center of this simply supported tube, it would deflect about .0002". If the tube was layed on it's side and the same conditions apply, it would deflect about .0006". A 4"X4"X.120" tube would deflect .0001" - theoretically, of course.
So Geoff's guess is proven to be OK, I guess. It's luck, I am sure....
Scott