[AT] OT...Need some advice on old metal building

[Len Rugen]

Are the on the ridge?  A long time and several brain cells ago, I worked 
on something that had heads on the ridges.  The rubber washers were 
gone, so the screws were a little loose.  A saws-all took them off 
pretty good, but we were trashing the metal, so a stray slice didn't hurt.

I can guess that if they are in the valley and tight, it wouldn't work....