On 7/7/2011 1:04 PM, -MIKE- wrote:

ASAIK, the heat treating done to drywall screws makes them resistant to
stripping out at the heads and resistant to breaking from the friction
of being driven by powered drivers. The treatment also makes them very
brittle and not good for resisting heavy shear loads, like on holding up
decks or cabinets.

Screws are not designed for shear loads. Screws are really just clamps
and they work by clamping two pieces of wood together.

I guess a screw expert might come up with a bunch reasons they should be
only used for the intended purpose, but my experience, which is
considerable, is they work fine for most, not all, things wood.

I agree with you on the heat treating of DW screws making them more
brittle, they don't bend like a regular steel screw, but the heads
simply NEVER strip out.

I've been using them (not exclusively of course) for many years, and
don't recall ever snapping one. That's why I did the test. I don't
recall driving any screws into Oak w/o drilling a pilot hole, so I gave
it a shot, and reported what happened. Anyone with an impact driver,
drywall screw and a hunk of Oak can test it themselves. That doesn't
mean they are unsnappable, just that they work good enough that snapping
is not that much of an issue.

--
Jack
You Can't Fix Stupid, but You Can Vote it Out!
http://jbstein.com