I have come to learn that drywall screws are not appropriate fasteners
for applications in which they might be subjected to any kind of
dynamic load. They are very hard, which for their intended application
is a good thing- but this hardness causes them to be very brittle.
A number of years ago I was supervising a commercial construction site
that was visited by an OSHA inspector. One of the contractors doing
high work had built a guard rail using drywall screws. The inspector
turned white as a sheet and made the contractor remove the assembly
immediately. He shared with us some pictures of structure failures
caused by using drywall screws in ways they were not intended. I was
busy recalling the saw horses I built once using drywall screws that
collapsed under a 300 lb. load when I accidentally bumped into them
with my hip.
While drywall screws are handy and inexpensive, I won't use them in any
application in which they might be subjected to movement of any kind,
or in which failure could have severe consequences. A couch might be
okay; however there are other potential applications in an A/S that are
certainly not okay.
Best,
Chris K.
1979 Int'l @31'
#8638