Ron, we have the same signs in regards to metal, and that is also how I get their attention, by bouncing the end gate open and closed.
We also have the universal telephone sign plus pointing at your ring finger which means the wife or girlfriend is calling.
Throat slash means either Stop of Finished.
A stroking motion with one forefinger across the first joint of the other means fraction, usually 1/2
pointing poth forefingers out with your arms extended and then making up and down movements with your arms means forklift.
a wrapping motion using both hands means a lift of lumber either is done, or needs to be banded and removed if followed by the forktruck sign.
Forefinger pointing down tracing an elongated circle away from you means turn on the sawdust conveyor.