RFGuy wrote
It seems to me like you are testing the worst-worst case here. I say that because aren't you applying a non-distributed load to the drawer bottom in your test apparatus?
Thanks RFGuy, your observation is spot-on (pardon the pun :D ).
I did it that way for two reasons. First, to be intentionally conservative. Second, and more importantly, because I didn't have much choice with that quick-and-easy apparatus implementation. Even with the small load pad I used, the straightedge has to be place slightly off-center on the test specimen, which means the measured deflection is a little less than the actual deflection. With some sort of large load-distributing pad, I couldn't even get close to the center. The bathroom scale blocks measurement access to the topside of the specimen (unless perhaps you could establish the compressive stiffness of the bathroom scale, and measure how far
it moves), and my CNC doesn't have enough vertical range for me to elevate the specimen and measure its underside. So not wanting to spend a lot of time on this, I just followed the KISS rule.