Questions: self drilling/ tapping screws for chassis work

profdant139 wrote:
Cummins, thanks for the tip -- I see that the underside of the head is serrated, which will serve the same function as a lockwasher, I think??

It would if you ran it down to the metal, but if you use it to attach the coroplast, or something similar, it won't work as well. But if attached to metal, then yes, it's works very much like a lockwasher.