[OP]
Member
I need to countersink many standard square-drive drywall screws (stingers), 1-1/2" length.
Not sure which Dewalt drill/countersink/counterbore combination bit is the right size... #12 #10 #8 #6 ?
HERE'S A LINK TO THE DEWALT SELECTION PAGE
I don't want to buy a set - just the one I need for the present application.
I'm buying via Amazon.com so can't hold up a screw in front of the bit to check for myself.
Thanks
Contributor
The answer to your question is #8.
However - I have to ask - what material are the screws going into, and why-oh-why use drywall screws? Not really the best idea for woodworking.
If you are going into softwood and/or plywood, you don't really need the countersink feature - simply drill a pilot hole with your basic 3/32" twist drill bit, and the screw threads will pull the screw head flush.
If you are going into hardwood with drywall screws, that road is fraught with danger.
When I started woodworking, I didn't know squat. I have progressed in 30 years - now I do know squat.
Member
most dry wall screws are number 6 so I would say number 6 I do have some number 8 screws.
Member
...and headless screws!Originally Posted by Kent A Bathurst
[OP]
Member
#8 AND #6...
No clear answer, just like the rest of this Life.
I need to know for sure so I can purchase the correct bit for typical, black, square-drive screws - 1-1/2" length. I'm using the kind with heavy/aggressive thread (not the dinky thread for metal studs).
I'm screwing through a piece of 1/2 plywood, into a piece of 2x construction stud. I'm not building furniture or a grand piano). Just need quick, accurate one-step holes. I'm doing this on a drill press.
So does anybody know for sure?
Thanks
Member
Why can't you determine if your screws are #6 or #8 and then just buy the correct countersink.
If you google 1-1/2" drywall screws they come in both sizes.
Contributor
Just buy a Peachtree set. They're nice ones, and you'll have the right one for this, and any future project.
Never, under any circumstances, consume a laxative and sleeping pill, on the same night
Member
1.5" is most likely #8, most #6 drywall screws are going to be 1 1/4 or 1 5/8"You should have. No problem countersinking a 1 1/2" #8 screw with a #6 countersink with ply into softwood though.
Member
It would seem that you have limited experience (or equipment) for working with drywall screws. Most people install drywall screws with a power drill only, without drilling a hole in advance. These screws are meant to go through drywall and then fasten them to wooden studs. Countersinking is usually not necessary in dry wall (because the drywall compresses under the screw), and, in my experience, utility grade plywood also compresses sufficiently so that countersinking is not necessary. Only hardwood faced plywood or hardwood might resist enough to require countersinking.
If you don't mind the dimple that a drywall driver makes, use a driver that is specially designed for drywall work and you will be done in no time. I recently bought a drywall driver from Harbor Freight that was inexpensive, although I did have to by a few driver bits to fit the screws that I had.
My suggestion is to take a few of the screws that you intend to use and drive them by hand into the materials you intend to use. You may pre-drill if you choose, since you are only testing to see how much effort it takes to drive the head flush. If you are able to sink the screw heads flush without too much effort using only manual effort, you shouldn't need to countersink any of the screws, (unless you are doing it for the sake of appearance). Don't bother pre-drilling when you do your actual assembly, since any power drill you use will have the power to drive the screw into the work. An inexpensive impact driver is also a good choice for driving screws into any difficult material, and since it turns slower than a regular power drill, you will have more control. Also a cheap right angle screw driver (a small driver, often with a ratcheting head, like a mini-socket wrench) is great for applying the force needed to adjust screws that aren't quite set properly.
In any case, I think you would be wasting a lot of effort to pre-drill, countersink and then screw your work together. The only reason I can think of to pre-drill is that you can get the screw to go in more perpendicular to the surface. You can handle that issue by using a hammer to tap the screw, like a nail, into the work prior to actually driving the screw. Another method that I've tried is taking a small spring clamp, filing a notch in the jaws, and using that to hold the screw while I drove it in under power. This avoids the need for you to hold the moving screw with your fingers.
Contributor
As noted above, there are both sizes.
Not to be too succinct, but why don't you grab a 1-1/2" #8 wood screw and a 1-1/2" #6 wood screw, compare them to your drywall screws, and make the determination on your own, rather than counting on some fool from Atlanta to make an accurate blind call....compare barrel diameters and head diameters.
Seems like it should pretty straightforward to decipher without a Rosetta stone - not exactly ancient Egyptian hieroglyphics or anything
As another observation, with the material being ply and studs, there is a modest risk of "holes too loose" from #8 hole and #6 screws. There is zero danger of "holes too tight" from #6 hole and #8 screw, because the drywall screws were intended to fire into studs with no pilot hole, and the torque will pull the head flush into the slightly-undersized countersink.
When I started woodworking, I didn't know squat. I have progressed in 30 years - now I do know squat.
Contributor
You too, eh Ben?
When I started woodworking, I didn't know squat. I have progressed in 30 years - now I do know squat.
Contributor
A counter sink in 1/2" ply leaves very little meat for the (drywall) screw to hold onto & because of the bugle shape it's "split city" when you drive the screws tight...I'm screwing through a piece of 1/2 plywood, into a piece of 2x construction stud.
I'm, speaking from very recent experience here - like in just last week.
I ditched the drywall screws (1 5/8" - using a # 6 countersink) in favor of 1" 23 ga pins and glue.
Member
A little browse of McFeely's might be in order...
Member
+1 on McFeeley's. I just put 9/16 OSB on several walls of my garage, about 25 4x8 sheets. I bought a 5# container of 1.75" spax screws, and it worked well. It was much easier to predrill the holes with the board on the ground, but no countersinking was necessary. The spax screws were WAY stronger and easier to work with than drywall screws (which I used on one panel while waiting for the spax screws to arrive...)
Contributor
Screwing plywood to framing lumber woulfd indicate that it is either for blocking (backing), or is structural. If it is for structural then nails and glue is the preferable method. If you ar planning on having it removable the screws are the way to go. If you do not have a power nailer for the project and wish to screw then the drywall screws are acting as a clamp until the glue sets since drywall screws are not approved structural fasteners in which case either a 5/32" or 3/16" will give you an adequate through hole in the ply or OSB whichever you are using to clamp the sheet to the stud. Deck screws on the other hand are strucural in nature but more expensive but should have a through hole provided for them as well. Screwing two pieces of anything together is always better with a through hole as technically you are clamping one to the other which is stronger than forcing the screw through one piece into the other which also always results in the two pieces never being tight to one another. With all that being said without glue you are expecting an non-structural screw to act as a structural fastener which it is not. BB stores have bulk structural fasteners at reasonable prices if you prefer to not or are unable to use glue. Either way you are clamping and a through hole in the sheet goods (other than drywall obviously) is the prefered way. A drywall screw in either application with or without glue is merely nothing more than a clamp and a very brittle one at that.
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