Drywall-type screws with true 82 deg head?

Awl --
I'm a big fan of coarse thread drywall screws, for mounting metal to wood (indoors), or even deck screws, but the head is not an 82 deg c-sink, in
fact, the underside is curved.
Can I get a drywall-type thread (coarse) with an 82 deg head (or 90 deg, any standard c-sink angle)? Traditional sheet metal screws have a large-ish root diameter, not enough "bite" in the threads.
--
EA



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You've brought this subject up before, and I don't think you'll find anything with an accurately countersunk head at any home stores, if they exist at all.
I mentioned before that I firmly believe the deck/construction screws are far better fasteners as thay aren't brittle like many/most drywall screws. Brittle drywall screws tend to snap, and deck/construction screws are tough but don't appear to be thru hardened. I prefer the deck type with the notched tips, which enable them to cut as they penetrate, making them easier to drive (longer lasting battery life on cordless drill/drivers).. and generally less likely to strip out the drive recess before they're driven home.
You may need to stamp/press a recess in the (sheet?) metal parts so the screws stop flush or slightly below the surface, or use a stamped washer that will deform to the bugle-shaped underside of these types of screws (there's a dressy-looking washer type like a hollow half donut, but I can't recall what their name is). Of course if the material being mounted is thick enough, a counterbore will get the head below the surface. Mo money, but plastic plugs are available in a multitude of styles.. but then, you've got CNC, so, no problem.
--
WB
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And therein lies the problem, the material is not thick, AND it is critical that the screw head be flush or below the metal tube's surface. Indeed, deck screws are a superior screw, seem almost identical, geometrically, to drywall -- altho drywall screws can come in very long lengths. As I look at some boxes, they say "construction fasteners", but they sure do look like dry wall/sheetrock screws to me. But I guess outdoor stuff is plated.
Anyway, what I may have to do is turn down the heads on these screws in a lathe, as they are wider at the top than I need, and hopefully they'll fit better in a std c-sunk hole. Hopefully I won't have to *face* them as well!! Hopefully some custom/specialty house will have some extras from someone else's order/run.
--
EA


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ood

in

g,

ugh

Would seem easier to construct a custom countersink if that style screw is what you need than to try to reshape the screws themselves.
Stan
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On Thu, 21 Feb 2013 15:18:26 -0800 (PST), Stanley Schaefer

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Would seem easier to construct a custom countersink if that style screw is what you need than to try to reshape the screws themselves. ============================================================ That's an inneresting idear, which I briefly thought about. I was also thinking about some kind two-step process, like 1 pass with an 82 deg c-sink, followed by a ball mill, perhaps even a ball mill with interpolation. But even that is a pita.... but a possibility.
Ooops.... not a ball mill.... a quarter-rounding tool, if the "nose" could get in the hole -- and it proly couldn't.
Custom tooling is no $$ picnic, either, and waaaay beyond my grinding skillset.
--
EA



Stan
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Existential Angst wrote:

Sounds like what you want is a trim head screw McMaster Carr 91530A774 might do the trick
--
Steve W.

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On Thu, 21 Feb 2013 18:13:38 -0500, "Existential Angst"

What you are looking for is undercut flat head screws. The head is undercut for use in thin materials. What are you drilling into where you think you need the smaller root diameter? Is the material especially soft or weak? Eric
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Existential Angst wrote:

What is the problem with traditional wood screws?
looking at Mcmaster, drywall screw #99136A100     http://www.mcmaster.com/#cadinlnord/99136a100/=lkwr59 it is clearly the bugle head you do not want.
but part #90031A153, a No. 6?#2 Phillips Drive Zinc-Plated Wood Screws appears to be what you are looking for.     http://www.mcmaster.com/#tapping-screws/=lkwsvp
Stephen B
--
not that other Steve B That posts frequently



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[...snip...]

The only question I have about these, are they soft metal like you often see in the home centers, or are they heat treated like you find with McFeeley's. The right heat treatment makes the screws tough but not brittle.
Having used heat treated screws before, I hate using the run of the mill stuff anymore.

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wood

in

deg, any

enough

Mcmaster Carr probably has something that was engineered to do whatever it is you are wanting to do.
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They use them all the time in production woodworking, Go to McFeely's and look around.
http://www.mcfeelys.com/product/0612-FRL/6-x-1-14-Wood-Screws-Unplated-Steel-Flat-Head-Combo-Drive
Paul K. Dickman
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