- This topic has 47 replies, 33 voices, and was last updated 4 years, 10 months ago by
.
-
Posts
-
So I’ve about had it with these guys I’ve been working with…they drive screws into PT lumber so you can’t even see them anymore- probably until the 1″ bit insert bottoms out on the Lumber and they can’t drive them deeper.
Personally, I set screws about 1/16″ below the surface.
I’m confident that my method is better, but what do you think?
Jon P.
Timber Carpentry & Construction
https://www.facebook.com/timbercarpentry/
InstagramYou should drive them just under the surface. You should be able to take a putty knife and NOT hear an audible “click” from the putty knife hitting the head of the sctrew. I use this technique with drywall but it transfers to any counter sunk screw IMO.
Too deep and you loose holding power.
I am with you on this one. The only reason you would drive screws that deep is if you were in a pinch and had screws that were too short that you needed drive them in farther to get them into the piece of wood underneath.
Otherwise the screws should only be driven a little below the surface, it makes it easier to remove the screw if necessary because you can see the head.. It also is stronger because more of that screw is in contact with the board you are drilling it into (contacting more surface area) instead of boring a hole through it.
Another thing you can argue is that with pressure treated wood, by drilling the screw that deep, you are creating a hole/channel that moisture can get into in the part of the wood that isn’t sealed. PT is only treated on the surface and even when you cut an end off you are supposed to re-seal it. You would almost have to do the same thing when drilling such a deep hole into it.
It’s flush or 1/16″ below the surface. No need to bottom out the screw and ruin the item you are working on. Consistency is the key.
I am with you on this one. The only reason you would drive screws that deep is if you were in a pinch and had screws that were too short that you needed drive them in farther to get them into the piece of wood underneath.
Otherwise the screws should only be driven a little below the surface, it makes it easier to remove the screw if necessary because you can see the head.. It also is stronger because more of that screw is in contact with the board you are drilling it into (contacting more surface area) instead of boring a hole through it.
Another thing you can argue is that with pressure treated wood, by drilling the screw that deep, you are creating a hole/channel that moisture can get into in the part of the wood that isn’t sealed. PT is only treated on the surface and even when you cut an end off you are supposed to re-seal it. You would almost have to do the same thing when drilling such a deep hole into it.
The moisture entering into the wood is an excellent point.
Yeah flush or slightly below surface, why would one want to crush all that wood fibers under the screw head, and probably the ones around the thread so the hold is weaker?
The moisture entering into the wood is an excellent point.
That’s the best argument I have heard.
It’s flush or 1/16″ below the surface. No need to bottom out the screw and ruin the item you are working on. Consistency is the key.
Agree with that. Driving screws any deeper is not necessary for holding power. 1/16″ is enough to ensure they will not be exposed after the wood dries completely and shrinks a bit.
I think a lot of those who bury the screws are just plain lazy and can’t be bothered with doing the job right.
BE the change you want to see.
Even if you can’t Be The Pro… Be The Poster you’d want to read.Just below surface . Water would go in all the holes you make , weakens wood, harder on the impact driver.
The only time I’m burying a screw that’s not being driven in at a severe angle is when I’m trying to suck two pieces together.
Another thing you can argue is that with pressure treated wood, by drilling the screw that deep, you are creating a hole/channel that moisture can get into in the part of the wood that isn’t sealed. PT is only treated on the surface and even when you cut an end off you are supposed to re-seal it. You would almost have to do the same thing when drilling such a deep hole into it.
That point right there should end the argument. Hey jponto, Tell them if they drive em that deep they’ll have to go back and seal the holes LOL
Actually the screw head should be proud of the material, snug against the material. In most cases it would be flush to the surface only after using a countersink bit.
Mark E.
Pioneer, CA
Working Pro 1972 - 2015
Member since Jan 22, 2013
www.creative-redwood-designs.comDepending on the application, I am in the flush to barely counter-sunk camp, nothing but disadvantages to over-driving screws, be it drywall, PT lumber, or hardwood.
W
Will
You don’t say what application this is in, but driving screws that deep is never the proper way to do it.
If you are face-driving deck screws, it is acceptable to “self-countersink” them. Some deck screws even have a little cutter head built into the screw, to facilitate countersinking.
In structural applications, overdriving a LedgerLok or such type, would be an automatic fail from your inspector. Same with overdriving nails in shear walls. The large head must not break the surface of the wood fibers, otherwise it’s holding power is greatly reduced.
Burying screws in a board is just a DIY/rookie move.
Delta
Goin' Down In Flames........
pressure treated wood, by drilling the screw that deep, you are creating a hole/channel that moisture can get into in the part of the wood that isn’t sealed. PT is only treated on the surface and even when you cut an end off you are supposed to re-seal it. You would almost have to do the same thing when drilling such a deep hole into it.
Great point,
@Doobie That’s another good one, I have done that a couple of times.Just below the surface.
Actually the screw head should be proud of the material, snug against the material. In most cases it would be flush to the surface only after using a countersink bit.
Mark,
This from a deck builder. Interested in your reasoning.I have not done that as I hate it when shoveling snow and the blade of the shovel gets hung up on anything.
“If you don’t pass on the knowledge you have to others, it Dies with you”
— Glenn BottingDrive them as far as you can! Kidding. I normally am flush or a little bit under the surface. I tend to go under the surface if I am going to eventually hide the screws.If you can see them, I try to stay flush
Jim H.
Milwaukee, WIRecessed just a hair.
If covering the screw with a dowel, 3/8″ deep to half the thickness of the wood.
Burying screws in a board is just a DIY/rookie move.
That’s the impression I got.
My partner hired these dudes to lay a bunch of gravel for a small parking lot (they have done concrete work for him before). That job grew into replacing a stair case from the parking lot up to another lot about 5 feet up.
No idea why he didn’t ask me to build the stairs…they started them on Monday afternoon and just “finished” a couple hours ago.
Jon P.
Timber Carpentry & Construction
https://www.facebook.com/timbercarpentry/
InstagramAnother thing you can argue is that with pressure treated wood, by drilling the screw that deep, you are creating a hole/channel that moisture can get into in the part of the wood that isn’t sealed. PT is only treated on the surface and even when you cut an end off you are supposed to re-seal it. You would almost have to do the same thing when drilling such a deep hole into it.
That point right there should end the argument. Hey jponto, Tell them if they drive em that deep they’ll have to go back and seal the holes LOL
I like Boyds answer
I don’t understand why someone would sink screws that deep, that means most of the wood at the top doesn’t contribute to the holding strength any more. And like Boschmanbrian said, the core of the PT gets exposed at that point.
Its like overdriving nails into sheathing…
Drive em so they’re flush or a little countersunk would be more or less my answer to this.
- You must be logged in to reply to this topic.