Drywall-type screws with true 82 deg head?

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.

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.

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

Construction screws and deck screws are a lot different than drywall screws - and a lot stronger. Most are coated with a ceramic type coating to protect them from corrosion from pressure treated wood and normal outdoor corrosion, blus act as a lubricant to make the screws easier to drive. Drywall screws are generally #4 or #6 - construction and deck screws #8 and up.

What is the problem with traditional wood screws?

looking at Mcmaster, drywall screw #99136A100

but part #90031A153, a No. 6?#2 Phillips Drive Zinc-Plated Wood Screws appears to be what you are looking for.

Stephen B

Mcmaster Carr probably has something that was engineered to do whatever it is you are wanting to do.

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

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

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.

They use them all the time in production woodworking, Go to McFeely's and look around.

Paul K. Dickman

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.