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john wrote:

Ned Simmons wrote:

In article ,
says...

Proctologically Violated©® wrote:

How did you determine what an "acceptable" deflection would be?
Building codes?

i personally use the moment and bending stresses , and a safety
factor of 3 to four , with 36000 psi being a standard for most beams
you dont want to get over 9 to 11 k in the bending and moments

The AISC standard uses a factor of safety of 1.67 in most cases, which
results in a working stress of 21.6 ksi for A36 steel.

you will see deflections of less that 1/16 inch for a properly
designed beam , while anything over 1/8 inch you will see the bending
and moment stresses edgeing up into unacceptable levels

That's a huge oversimplification. A deflection much greater than 1/8"
is acceptable in a long beam, and a very short beam may fail, probably
in shear, before it deflects 1/16".

Ned Simmons

On a cantilever beam hoist you want to keep the deflection to a minumum
because with a heavy load it will want to roll down hill in the
direction of the negative deflection. It will take off by itself when
you hoist a load, and that can get exciting.

True enough, but what's "a minimum" in that context? The load needs to
be pinned, held by cable, etc. to restrain the horizontal motion.

Bill