In article ,
says...
Richard J Kinch wrote:
Observe that the forces on a bender footing are torsional around a vertical
axis, not so much in the other 5 degrees of freedom. ...

I don't think so. Consider this thought experiment: a 1/4" rod, 4'
long, anchored vertically in concrete, with a 2' horizontal handle
attached at the top. Pull horizontally on the handle's *end*,
perpendicular to it. How does it deform? Mostly by bending in a
vertical plane and not as much around its axis.

But...as the handle gets longer, assuming a constant force applied at
its end, the tendency to bend the rod does not change, but the twisting
moment increases with the length of the lever. So at some point the
shear on the fixing bolts will exceed the tension.


I'm sure that a mechanical engineer could tell us just how much in each
"degree", but I'm not up to that.


Just keep repeating,

The sum of the forces equals zero;
The sum of the moments equals zero;
You can't push a rope

All you need to know to be a CE g.

Ned Simmons