Sheet rock screws: fine vs coarse thread?
Existential Angst
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
Ed Huntress
"Existential Angst" <UNfi...@UNoptonline.net> wrote in message
news:4bc4d846$0$21869$607e...@cv.net...
> 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.
--
Ed Huntress
DerbyDad03
wrote:
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.
Stuart Wheaton
About any screw you might want, and square drive is the ONLY option as
far as I'm concerned!
Stuart
DerbyDad03
>
> - Show quoted text -
re: "square drive is the ONLY option as far as I'm concerned!"
Unless you think you might find yourself with the need to disassemble
what you've put together and there's a danger of no (or not enough)
square drive bits being available.
I'm often involved in set-up and tear downs for events where lots of
dry wall screws are used. You can *always* find a screw gun, usually
with a # 2 phillips bit already installed, within arm's reach. Try
locating a square drive bit - and of the right size - when something
needs to fixed/adjusted with moment's notice.
When it comes to volunteer events like these, you want to go with the
most common fasteners so that anyone (and everyone) can pitch in. # 2
phillips screws are still the most common and I don't see that
changing any time soon - even if square drives are better.
Wes
>About any screw you might want, and square drive is the ONLY option as
>far as I'm concerned!
Robertson screws are pretty good but the ones with torx heads are really awesome. I
re-pitched a roof once with adder trusses held on by torx fasteners that screwed into the
original trusses. Long as they were, they never stripped. Unlike some Robertson screws
I've used in building decks.
Wes
--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller
David Nebenzahl
> 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
Thanks for that; excellent article. Pretty much jibes with my own
experience with drywall vs. wood screws. I much prefer coarse threads
for wood. (Never used fine-thread drywall screws for their original
intended purpose of securing to metal framing.)
--
The fashion in killing has an insouciant, flirty style this spring,
with the flaunting of well-defined muscle, wrapped in flags.
- Comment from an article on Antiwar.com (http://antiwar.com)
Oren
<hunt...@optonline.net> wrote:
>That was before sheet rock
>screws.
Yep, nails ("blue nails") and a lath hatchet. <G>
Ed Huntress
"Wes" <ClutchAtL...@Gmail.com> wrote in message
news:Sb6xn.371477$Hq1....@en-nntp-04.dc1.easynews.com...
> "Ed Huntress" <hunt...@optonline.net> wrote:
>
>>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.
>
> (no studs having
> conduction from inside to outside for my machine room. The studs are
> tamarack, fine pitch
> was easier to use but I did finally resort to drywall nails, some that
> bent over. For a
> soft wood, tamarack sure doesn't know it.
>
> Generally fine pitch is for steel studs iirc.
I'm sure there are exceptions. What the Gougeons learned first was that
conventional wood screws didn't hold as well as sheet-metal screws in any
wood they tested, probably due to their deeper and fuller threads.
--
Ed Huntress
sta...@prolynx.com
>
> - 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
Wes
>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.
Normally I'd go with what you said but, I constructed two envelope walls (no studs having
conduction from inside to outside for my machine room. The studs are tamarack, fine pitch
was easier to use but I did finally resort to drywall nails, some that bent over. For a
soft wood, tamarack sure doesn't know it.
Generally fine pitch is for steel studs iirc.
Wes
Dave__67
And never use drywall screws for staging.
Dave
LSMFT
I agree. Less hassle getting enough torque. No phillips chatter.
--
LSMFT
I'm trying to think but nothing happens.........
JIMMIE
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
Ned Simmons
<ClutchAtL...@Gmail.com> wrote:
>Stuart Wheaton <sdwh...@fuse.net> wrote:
>
>>About any screw you might want, and square drive is the ONLY option as
>>far as I'm concerned!
>
>Robertson screws are pretty good but the ones with torx heads are really awesome. I
>re-pitched a roof once with adder trusses held on by torx fasteners that screwed into the
>original trusses. Long as they were, they never stripped. Unlike some Robertson screws
>I've used in building decks.
I bought a package of Torx head deck screws for erecting pump staging.
It's nice to not have to push on the driver at all when you're up on a
ladder and reaching as far as you can to fasten the pole braces.
Expensive, but much better than Phillips or Robertsons.
--
Ned Simmons
Ted Frater
A couple of yrs ago I built for my daughter's old cottage in Wales some
new kitchen units.
She wanted then out of solid wood, in the medieval style. The framing
was from 4 by 2 with the tops in 2in thick all from cedar inc the doors
which were 1in thick, boards some 20in wide.
These boards were planked up when she was 6 and put by. I used them for
her some 19yrs later!!.The wood came from her school at that time as we
had had the storm of the century and most of the school trees were blown
down. I helped to clear up the resultant damage.
To fix the frame to the top from the underside needed 3&3/4 in screws.
I pilot drilled the 1st 2in through the framing then the remainder
with ,would you believe my 1/2in car wheel nut air hammer. the screw
heads were countersunk no3 pozidrive and nothing put them in better or
faster.
Thought it might just be of interest, as no other power tool would work
to pull them up real tight. Didnt cam out any.
ted
in Dorset
UK
Larry Jaques
<ClutchAtL...@Gmail.com> scrawled the following:
>Stuart Wheaton <sdwh...@fuse.net> wrote:
>
>>About any screw you might want, and square drive is the ONLY option as
>>far as I'm concerned!
>
>Robertson screws are pretty good but the ones with torx heads are really awesome. I
>re-pitched a roof once with adder trusses held on by torx fasteners that screwed into the
>original trusses. Long as they were, they never stripped. Unlike some Robertson screws
>I've used in building decks.
Yeah, my head favorites, in order of favor are: Torx, Robertson,
Pozidrive (square and phillips), and Phillips.
For repair work a year or ten later, Robertson/square beats them all.
A nail or screw pushed into the recess removes enough dirt and grit to
allow the drive to remove the screw without stripping. I keep a camera
lens puffer (rubber bulb with small brass tube for blowing) in the
truck for things like that. It saves a whole lot of time and
frustration when you don't have to drill out any hardened screw heads.
--
Climb the mountains and get their good tidings. Nature's peace
will flow into you as sunshine flows into trees. The winds will
blow their own freshness into you, and the storms their energy,
while cares will drop away from you like the leaves of Autumn.
-- John Muir
Stuart Wheaton
The problem you mention is easily solved by having a few packages of #2
square drive bits. I work in Theatre, we put up and tear down all the
time, and there is NO comparison, esp if the head has some paint in it.
Also, if a square drive bit becomes slightly worn, it can usually be
re-conditioned enough to finish the show, just by lightly tapping it on
a running belt sander, you can't do that with a phillips. I have known
places that used one type of fastener for all permanent inventory, and
the other fastener for stuff that is meant to last just for the show.
then if only one driver type is on the deck at strike, the good stuff
gets saved.
BTW, screws are a single use item. The biggest source of frustration is
trying to save and re-use screws.
DoN. Nichols
[ ... ]
> 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.
When my old workplace (a government R&D lab) let out a contract
to re-cover all the 30-year-old linoleum-topped metal desks with new
fake wood (particle board with wood-grain print plastic on it), they
simply dropped the new top over the existing one (made to be a pretty
good fit with sides which overlapped the metal top sides), and used some
intersting screws. At first glance, they looked like drywall screws,
but examining one showed that instead of having a sharp spiral point,
they had a drill bit point, so they would drill through the metal and
then thread in -- going into pre-drilled and countersunk holes in the
sides of the new top.
That is now about twenty years ago, so I wonder what the desk
tops look like now. :-)
Enjoy,
DoN.
--
Email: <dnic...@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
DerbyDad03
re:
1 - "The problem you mention is easily solved by having a few packages
of #2 square drive bits..."
2 - "BTW, screws are a single use item"
1 - Not really and 2 - not in all cases.
At the events that I'm talking about, the equipment that is used by
the competitors require - by rule - upwards of 40 # 2 Philips head dry
wall screws. Therefore, that is the bit that everyone has in their
screw guns. Square drive screws are not an an option in the
competitor's equipment. The screws for the competitor's equipment
don't get stressed or torqued very tight, so they are used over and
over and over again with no damage. The only time they get replaced is
when they get lost or rusty.
Now, as for the set up and tear down portions of the events, the
organizers opt for # 2 Philips head screws of various types and sizes
so that we're not constantly looking for and changing bits depending
on whether we're working on the competitor's equipment or the event
infrastructure. I know that these screws are single use items, but
there are many "helpers" who don't.
At one point I snuck in a bunch of those Deckmate screws that took the
square tip Phillips bits. I used them for the heavier construction
parts of the set up. Talk about Phillips bit chatter when other people
tried to take apart the stuff I had built! I was promptly told to
stick with standard # 2 Phillips in the future.
The Daring Dufas
I have two screwdrivers I carry in my pockets whenever I'm working.
The drivers have flat, Torx, Phillips and square bits because I
never know what I'll run into. The bits can also fit a power driver.
A good pocket screwdriver is hard to find and I found the best I've
ever owned a W W Grainger. It won't poke a hole in your pocket when
it's closed up with no bit in it.
http://www.grainger.com/Grainger/items/5PA35?Pid=search
I also carry a lot of other stuff in my pockets that keeps me from
having to run back to the van for a tool.
TDD
The Daring Dufas
It seems like all of the new electrical panels I'm coming across these
days are using square drive screws or combo screws that will work with
flat, square or Phillips drivers. I like the torque handling capability
of the square drive screws and the absence of cam-out slippage.
TDD
Lloyd E. Sponenburgh
news:slrnhsadd7....@Katana.d-and-d.com:
> At first glance, they looked like drywall screws,
> but examining one showed that instead of having a sharp spiral point,
> they had a drill bit point, so they would drill through the metal and
> then thread in -- going into pre-drilled and countersunk holes in the
> sides of the new top.
>
Yeah? (Um... they're called "self-drilling sheet metal screws". Any ACE
Hardware store will have them) <G>
LLoyd
Jules Richardson
> 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.
Maybe there are quality issues between brands? I've seen it before with
Phillips-head screws, where the amount of material forming the screw can
be a lot less from one vendor compared to another. The 'lesser' screws
just loved to snap when driven in, whereas the ones with thicker shafts
didn't. These days I always buy fastners from real stores (not online) so
I can check what I'm getting.
> 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.
Seen that on doors before - I think it's so they can be screwed into
different types of material while retaining strength.
cheers
Jules
Larry Jaques
<dnic...@d-and-d.com> scrawled the following:
>On 2010-04-13, DerbyDad03 <teama...@eznet.net> wrote:
>
> [ ... ]
>
>> 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.
>
> When my old workplace (a government R&D lab) let out a contract
>to re-cover all the 30-year-old linoleum-topped metal desks with new
>fake wood (particle board with wood-grain print plastic on it), they
>simply dropped the new top over the existing one (made to be a pretty
>good fit with sides which overlapped the metal top sides), and used some
>intersting screws. At first glance, they looked like drywall screws,
>but examining one showed that instead of having a sharp spiral point,
>they had a drill bit point, so they would drill through the metal and
>then thread in -- going into pre-drilled and countersunk holes in the
>sides of the new top.
>
> That is now about twenty years ago, so I wonder what the desk
>tops look like now. :-)
That was either a Type-17 or Self-drilling type tip, Don. Good
Schtuff(tm)! http://www.midstatesbolt.com/screwpoints.htm
I had seen and used only the self-drilling types up until half a
decade ago, when I found the nice Type-17 tips and Robertson heads on
better deck screws.
--
STOP THE SLAUGHTER! Boycott Baby Oil!
Larry Jaques
Richardson <jules.richa...@gmail.com> scrawled the following:
>On Tue, 13 Apr 2010 16:08:42 -0700, stans4 wrote:
>> 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.
>
>Maybe there are quality issues between brands? I've seen it before with
>Phillips-head screws, where the amount of material forming the screw can
>be a lot less from one vendor compared to another. The 'lesser' screws
>just loved to snap when driven in, whereas the ones with thicker shafts
>didn't. These days I always buy fastners from real stores (not online) so
>I can check what I'm getting.
All the local dealers carry are Taiwan-made GripRite screws. I lose
very few of those, though. I wonder if stans4 was driving 4" standard
tip screws into undrilled hardwood. I never lose screws going in, but
have lost a lot backing them out after they've been in. Half the
tip/screw is usually left in the hole when that happens.
>> 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.
>
>Seen that on doors before - I think it's so they can be screwed into
>different types of material while retaining strength.
As to screw reuse, if they're coated for pressure treated wood use,
they're pretty much a single-use item. Everything else is good for as
long as the drive head is usable. By using good and fresh tips in
your screw- and impact-drivers, you increase that lifetime and save
money down the line. (Tips cost under a buck.) And if there's one
thing I've learned about stripped screw heads, it's that you
immediately pull it out if you get even a slight strip (tip spin in
the screw head) on the way in. Otherwise, you'll get it almost seated
before it strips out completely and leaves you limited or no way to
remove it. This applies primarily to flat and phillips screws, but
other heads can strip, too.
James Waldby
> "DoN. Nichols" ... [wrote]:
>
>> At first glance, they looked like drywall screws, but examining one
>> showed that instead of having a sharp spiral point, they had a drill
>> bit point, so they would drill through the metal and then thread in --
>> going into pre-drilled and countersunk holes in the sides of the new
>> top.
>>
> Yeah? (Um... they're called "self-drilling sheet metal screws". Any
> ACE Hardware store will have them) <G>
But sheet metal screws don't look like drywall screws. More likely
they were Drill Point Drywall Screws, as shown at top of
<http://www.aaronswoodscrews.com/DrywallScrews.htm> and one screen
down in <http://www.smithfast.com/drywallthreads.html>. The latter
also shows (near the end, after the Trim Head Drywall Screws section)
Auger Point Deck Screws that look somewhat like drywall screws.
(With Type-17 point, as mentioned in the link Larry Jaques gave,
<http://www.midstatesbolt.com/screwpoints.htm>.)
--
jiw
harry
> On 2010-04-13, DerbyDad03 <teamarr...@eznet.net> wrote:
>
> � � � � [ ... ]
>
> > 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.
>
> � � � � When my old workplace (a government R&D lab) let out a contract
> to re-cover all the 30-year-old linoleum-topped metal desks with new
> fake wood (particle board with wood-grain print plastic on it), they
> simply dropped the new top over the existing one (made to be a pretty
> good fit with sides which overlapped the metal top sides), and used some
> intersting screws. �At first glance, they looked like drywall screws,
> but examining one showed that instead of having a sharp spiral point,
> they had a drill bit point, so they would drill through the metal and
> then thread in -- going into pre-drilled and countersunk holes in the
> sides of the new top.
>
> � � � � That is now about twenty years ago, so I wonder what the desk
> tops look like now. :-)
>
> � � � � Enjoy,
> � � � � � � � � DoN.
>
> --
> � � � � (too) near Washington D.C. |http://www.d-and-d.com/dnichols/DoN.html
> � � � � � �--- Black Holes are where God is dividing by zero ---
The screws you mention are for self drilling, self tapping holes in
fairly thick metal. The commonest place you see them is for fixing
steel roofing sheets to girders on agricultural/industrial buildings.
They usually come with a washer with a weather seal under it.
Existential Angst
> 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.
Heh, I'm surprised that some here have asserted that it is the fine thread
that's used on metal studs, coarse for wood.
Not disputing it, just surprised that this would be so, as it would seem
that the greater the ratio of major to minor diameter, the more grab
possible on thin sheet metal.
In fact, there's a company that exploits this with some fancy sheet metal
screws -- forgot their name, but I have a sample pack from them somewhere...
In re-thinking all this, pilot holes could be used to tailor any material to
a coarse thread. Except that, well, altho pilot holes are good, they are
also a pita.
I used to buy only fine thread, pretty much out of reflex, but now I find
myself much more leaning toward coarse thread, overall.
Plus, coarse threads are easier to tap, less chip binding it seems.
My understanding is that fine threads on big bolts is a torque/force
consideration, for getting mating stuff really tight.
But, other than that, I think fine threads may be pretty much superfluous
for general applications, unless, for example, metal studs really do call
for a fine thread screw.
Bottom line is, I think I've convinced myself to dispense with fine thread
anything, unless an application specifically benefits from a fine thread.
Sure will simplify the organization/storage aspect.
--
EA
> 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?
>
rangerssuck
wrote:
>
> 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.
> 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
Just my two cents worth:
I've always thought that the fine threads were for metal studs.
I've used the self-drilling ones in metal studs, but also in one room
in my house where the ceiling joists were made of something resembling
kryptonite. The normal sharp-pointed screws would just not screw all
the way in. The self-drilling ones shot right in.
Also, for what it's worth, coarse threads require fewer turns to screw
in, and therefore, go in faster.
Just sayin'
Bob Engelhardt
> ...
> Also, for what it's worth, coarse threads require fewer turns to screw
> in, and therefore, go in faster.
Ah, not so. Well, sometimes, maybe. The fine thread screws are
double-threaded, so they go in twice as fast as they would otherwise.
Bob
David Lesher
>Robertson screws are pretty good but the ones with torx heads are really awesome. I
>re-pitched a roof once with adder trusses held on by torx fasteners that screwed into the
>original trusses. Long as they were, they never stripped. Unlike some Robertson screws
>I've used in building decks.
WhatHeSaid! Torx is your friend....
--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433
rangerssuck
Now I gotta go look. But not 'till morning.
DoN. Nichols
> On Wed, 14 Apr 2010 06:28:43 -0500, Lloyd E. Sponenburgh wrote:
>> "DoN. Nichols" ... [wrote]:
>>
>>> At first glance, they looked like drywall screws, but examining one
>>> showed that instead of having a sharp spiral point, they had a drill
>>> bit point, so they would drill through the metal and then thread in --
>>> going into pre-drilled and countersunk holes in the sides of the new
>>> top.
>>>
>> Yeah? (Um... they're called "self-drilling sheet metal screws". Any
>> ACE Hardware store will have them) <G>
>
> But sheet metal screws don't look like drywall screws. More likely
> they were Drill Point Drywall Screws, as shown at top of
><http://www.aaronswoodscrews.com/DrywallScrews.htm> and one screen
Yes -- drill point bugle head blued like other drywall screws
I've seen.
> down in <http://www.smithfast.com/drywallthreads.html>. The latter
> also shows (near the end, after the Trim Head Drywall Screws section)
> Auger Point Deck Screws that look somewhat like drywall screws.
> (With Type-17 point, as mentioned in the link Larry Jaques gave,
><http://www.midstatesbolt.com/screwpoints.htm>.)
The first SELF-DRILLING in that list (just past "TYPE 25 POINT"
is exactly what they were using. And given the application, they made
sense. One tool (battery powered drill/driver), one screwdriver bit
(Phillips) and the screw which did its own drilling. Not what I would
have used to make a pretty job, but something which got the contract
done quickly. :-)
The screws were guided by the pre-drilled holes in the
replacement desk tops, and the steel which they had to drill through was
probably about 12 Gauge or thicker. (I never tried to measure it, but
those were *heavy* GSA steel desks.)
In case it matters, I'm in here from rec.crafts.metalworking,
not from alt.home.repair, so what I regularly work with is likely quite
different from what the ahr crowd (who is part of the cross-posting) does.
Twayne
Bob Engelhardt <bobeng...@comcast.net> typed:
No, they are not double-threaded. YOu're thinking of something
else. Coarse is just that; a much coarser thread, more
diameter than a fine, and fewer turns to drive in but I've
never found that to be an issue of any kind.
HTH,
Twayne`
benick
news:4bc4d846$0$21869$607e...@cv.net...
>
> 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
>
There are 4 types of screws typically used for drywall..
Coarse Thread from 1inch for pocket door walls to 3 inch for going over old
sheetrock/plaster , multiple layers in firewalls ...For use with WOOD studs
Sharp Point fine thread..Same as above except for use in METAL framing..
Self Tapping fine thread , sams as above but for higher gauge steel like in
exterior or load bearing steel framed walls..
Laminating Screws...Fat coarse thread 1 1/4 screws for laminating sheetrock
on steel framed walls as in stairwells or elevator shafts where sheetrock
thickness is an inch or more...
Other than sheetrock I use Torx...Square heads are good as well....
Bob Engelhardt
> Bob Engelhardt typed:
>> Ah, not so. Well, sometimes, maybe. The fine thread
>
> No, they are not double-threaded. ...
Well, rather than get into a pissing contest, I took a picture. It's a
drywall screw, with paint stick filling its grooves and a pick run in
one thread:
http://home.comcast.net/~bobengelhardt/DrywallScrew.jpg
That this DW screw IS double threaded is clear. I did not assert that
they all are - I haven't looked at all of them. Apparently you have
not either.
HTH,
Bob
Existential Angst
news:hq8f4...@news5.newsguy.com...
> Twayne wrote:
>> Bob Engelhardt typed:
>>> Ah, not so. Well, sometimes, maybe. The fine thread
>>> screws are double-threaded, ...
>>
>> No, they are not double-threaded. ...
>
> Well, rather than get into a pissing contest, I took a picture. It's a
> drywall screw, with paint stick filling its grooves and a pick run in one
> thread:
Dats a pretty ingenious technique!
Just looking at it, I would not have suspected double grooves!
I wonder what that double grooving really accomplishes, ito the mechanical
interaction between the screw and wood, or the screw and thin stud metal.
--
EA
Existential Angst
>> Bob Engelhardt typed:
>>> Ah, not so. Well, sometimes, maybe. The fine thread
>>> screws are double-threaded, ...
>>
>> No, they are not double-threaded. ...
>
> Well, rather than get into a pissing contest, I took a picture. It's a
> drywall screw, with paint stick filling its grooves and a pick run in one
> thread:
> http://home.comcast.net/~bobengelhardt/DrywallScrew.jpg
>
> That this DW screw IS double threaded is clear.
Heh, well, here's a tidbit of a factoid for you:
Dat double groove is a facsimile of DNA, the proverbial double helix.
The DIFF, tho, is, that while the spacing of the double groove in this screw
appears uniform, in DNA one helix is slightly offset relative to the other,
resulting in a "major groove" and a "minor groove".
Iow, to trace the "thinner" minor groove, your pick would have to be sharper
than for the major groove.
Oh, and for the record, my periodic diatribe against Watson and Crick :
Watson and Crick did not "discover" the structure of DNA.
Rather, they ROBBED the discovery from Linus Pauling, by pirating Roslyn
Franklin's x-ray data, cuz they knew if Pauling woulda seen it, he would
have deduced the structure *in minutes*.
Heh, talk about being sheet-rock screwed....
How does I know this?
Cuz Pauling had *already* correctly deduced the *triple helix* of the
protein alpha keratin, AND he had already deduced the double helix structure
of DNA!!!!
BUT, he had incorrectly placed the phosphate backbones on the inside,
instead of the outside.
So all he needed was a few of Franklin's x-ray dots, and BANG, problem
solved.
Also, fuknWatson obliquely admitted this in his book The Double Helix.
For some reason, Charlie Rose sees fit to regularly blow Watson on his show.
<MMMMmmmmmm>
Fuck Watson.
HTH :)
--
EA
Twayne
Bob Engelhardt <bobeng...@comcast.net> typed:
Improper attribution: I did not write that.
Twayne
Bob Engelhardt
> In news:hq8f4...@news5.newsguy.com,
> Bob Engelhardt <bobeng...@comcast.net> typed:
>
> Improper attribution: I did not write that.
>
> Twayne
You didn't write:
<quote>
In news:hq5b2...@news1.newsguy.com,
Bob Engelhardt <bobeng...@comcast.net> typed:
> > rangerssuck wrote:
>> >> ...
>> >> Also, for what it's worth, coarse threads require fewer
>> >> turns to screw in, and therefore, go in faster.
> >
> > Ah, not so. Well, sometimes, maybe. The fine thread
> > screws are double-threaded, so they go in twice as fast as
> > they would otherwise.
> > Bob
No, they are not double-threaded. YOu're thinking of something
else. Coarse is just that; a much coarser thread, more
diameter than a fine, and fewer turns to drive in but I've
never found that to be an issue of any kind.
HTH,
Twayne`
</quote> ?
In that case, somebody has hijacked your ID. Quite convincingly, too -
as I don't see any differences in the full headers.
Bob