On Apr 13, 7:08*pm, wrote:
On Apr 13, 3:37*pm, Stuart Wheaton wrote:



Ed Huntress wrote:
"Existential Angst" wrote in message
...
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?

The Gougeon Brothers of sailboat fame did tests of coarse- versus
fine-thread screws in wood back in the '60s. Coarse-thread won. Sheet metal
screws beat wood screws in wood every time. That was before sheet rock
screws.

www.mcFeelys.com

About any screw you might want, and square drive is the ONLY option as
far as I'm concerned!

Stuart- Hide quoted text -

- Show quoted text -

I dunno, I used quite a few pounds of square-drives putting up a
shed. *The drivers didn't wear like a cross-point/Phillips bit would,
but quite a few heads stripped out or screws snapped off without
driving home. *This was with decking screws, U.S.-made at that. *I've
used a whole lot of regular-type sheetrock screws and didn't have that
problem. *Wore out a bunch of driver bits, but never had a head
strip. *Haven't seen stainless drywall screws or I would have used
those.

Have a bunch of trim screws off of Fords I picked up in the scrap yard
that had interesting threads, went into plastic parts. *Were multi-
start threads, one start was coarse and heavy, like a sheetrock screw,
the other was shallow and thin. *Hadn't seen anything like that
before. *Seem to be pretty resistant to vibration, have to tighten up
the other trim screws after awhile, not those.

Stan

Yeah they do kind of a controlled bind-up but they are bad to strip
out if you put them in and take them out more than a few times. May
work better in wood than they do plastic.

Jimmie