Larry Jaques questions:

Yeah, if you accidentally drop 4 bowling balls on one
shelf of your glassware hutch at once it might cause the
whole thing to fall.

I've had failures in drywall screws, but it was from a
racking/bending force, not shear force. Have you had a
failure from shear?

I've had heads twist off with very low force--hand driven, in fact. So there's
no chance at all I'll ever have a shear failure in a real project with one. I
simply do not use them except to install wallboard.

Charlie Self
"I hope our wisdom will grow with our power, and teach us, that the less we use
our power the greater it will be." Thomas Jefferson