On Apr 13, 4:46*pm, "Existential Angst"
wrote:
Awl --

Purpose? *Applications?

The *minor diameter of the fine thread (under 2") appears to be about .115
(mebbe less, due to inadequate penetration of caliper edge), and .090 on the
coarse. *Ergo, more "grab" with the coarse.

I'm guessing the following:

Coarse thread is for sheet rock on metal studs -- more grab on studs.
* *Altho framing screws, which afaik are only for metal stud to metal stud,
also come in coarse and fine thread, so this may muddy this particular
logic. * Mebbe for different gauges of metal studs? *I've seen some much
heavier than others.

Coarse thread for particle board et al.

Fine thread for hardwood.

Opinions?

fyi, there exists a 3/4" and *1 1/8 SR xcrew, very hard to find.
The 3/4 is VERY handy, when screwing from the back side of a good face, and
the 1 1/8 occasionally comes in handy.
A good hardware store, proly one that sells SR screws by the pound, can
order a 25# box. *If he hesitates, tell him that the 3/4" will FLY out of
the store when people grok their utility.
--
EA

Typically, it's coarse thread thread for wood studs, fine thread for
metal studs. The fine thread screws also have a sharper point so they
are easier to start, *especially* when trying to pierce metal studs.

While you might think that you want coarse threads for more "grab" in
the metal studs, in reality you want less space *between* the threads
so that the thin metal can't move.

Here are some thoughts on using drywall screws for woodworking...

http://www.woodbin.com/misc/drywall_screws.htm

And we haven't even addressed the different types of heads on drywall
screws, from "standard" to bugle to flat.