Construction & Structural Screw Length Curiosity

[PJB12]

Hi All!
When looking for construction & structural screws, I found that the length of 3-1/8 inches is common. Three inch is not common.
Since typical "2-by" lumber is 1-1/2" thick and sometimes one wants to screw a "2-by" to another (such as a ledger board), why is 3 inch not more common?
Thanks,
Paul

 

[bud16415]

My go to screws for anything structural / nail replacement id the GaurdDog screw. They are designed for deck work but I use then anyplace I want a strong screw that’s easy to drive.



They come 1.625, 2.00, 2.50, 3.00 & 3.50 lengths.



I haven’t found too many times that one of those lengths didn’t work well.

 

[PJB12]

Wonder why 3-1/8" is so prevalent around here? (Instead of the hard-to-find 3") Maybe we have fatter wood.
Or in my case, can't run a screw straight so the extra 1/8 doesn't matter.

 

[Steve123]

In my woodworking, I am often frustrated by the standard lengths of common wood screws.

For example, if joining two pieces of 1/2" wood, I can either use 3/4" wood screws, which only give me a quarter inch of engagement, or 1" wood screws, which risks breaking through.

I find wood screws to often be a bit shorter than nominal but I don't think that is enough to ensure they don't break through. In the above example I often use the 1" screw, but grind a bit of the point off.

 

[PJB12]

In my woodworking, I am often frustrated by the standard lengths of common wood screws.

For example, if joining two pieces of 1/2" wood, I can either use 3/4" wood screws, which only give me a quarter inch of engagement, or 1" wood screws, which risks breaking through.

Screw size availability really must be a regional thing.
Steve123 mentioned that he can get 3/4" or 1" wood screws for joiining two 1/2" parts.

Around here, at hardware & home centers here, 7/8" and 1" are ubiquitous, but 3/4" is elusive. I think 7/8" would be great for Steve's 1/2"-to-1/2" project.

 

[bud16415]

Cabinetry wood screws and structural “deck screws” are two totally different categories as are the “drywall screws”. They are all kind of interchangeable but each have a place.



I have been told mixed messages about using structural screws as an alternative to nails as some feel they are too hard and wont bend before failure others don’t like them because of cost. Most of the work I do is repairs and small projects so ease for me outweighs cost and IMO the deck screws will out perform nails.



I often run them at slight angles intentionally as I feel the joints are even stronger and by angling a longer screw wont pop thru. I guess I’m old school but even when a screw point popping thru cant be seen I just don’t like it. My dad built our home when I was a kid and screws like today where not around. I remember him teaching me that framing nails should be clinched over when building a strong house. No one would do this today but it was a thing at least around here back then. Now nails have a glue coating and such so who knows.



My old wrists wont take a day of hammering nails any longer and if I make a mistake screws back out just as easy as they went in.



Sometimes with framing if I wish the screws were a quarter inch longer I just drive them in extra deep.



One thing with screws is the two pieces have to be tight together to get a good joint before driving the screw. Once in a while I will drill a pilot hole for the first screw so it will suck the two pieces together. When I’m making a beam by screwing and or gluing two lengths together I have a box of C-clamps I will put on first. Again it is a little time consuming for a commercial builder to do, but I have all the time in the world now.

 

[PJB12]

That's very explanatory what you wrote above, Bud16415. Thanks for posting it.

I've also read & heard framing nails versus screws arguments. In my life, I've found 3" framing nail gun nails bend easier than 16d nails. To me, both nails bend & pull out easier than construction or structural screws- but the screws snap instead of bending.

I just finished a project using structural screws. They snapped like crazy, even sometimes when driven by hand. Another brand, same size, did not snap at all- hand or driver or impact driver.

For more confusion, some screws called "Structural" have a lower shear and torque value than some "Multipurpose" or "Construction" screws. GRK RSS & GRK R-4 are examples. I guess reading data sheets is important. (For the record, the GRK are the screws that did NOT snap. They always work fine.)

I chuckled when I read what you wrote about bending over nails. My house has 20d bent over everywhere I look (or where my hand brushes). Still holding on tightly after more than 120 years!

 

[bud16415]

That's very explanatory what you wrote above, Bud16415. Thanks for posting it.

I've also read & heard framing nails versus screws arguments. In my life, I've found 3" framing nail gun nails bend easier than 16d nails. To me, both nails bend & pull out easier than construction or structural screws- but the screws snap instead of bending.

I just finished a project using structural screws. They snapped like crazy, even sometimes when driven by hand. Another brand, same size, did not snap at all- hand or driver or impact driver.

For more confusion, some screws called "Structural" have a lower shear and torque value than some "Multipurpose" or "Construction" screws. GRK RSS & GRK R-4 are examples. I guess reading data sheets is important. (For the record, the GRK are the screws that did NOT snap. They always work fine.)

I chuckled when I read what you wrote about bending over nails. My house has 20d bent over everywhere I look (or where my hand brushes). Still holding on tightly after more than 120 years!

I have tried a lot of deck screws and found the Guard-Dogs to have a good strength to hardness ratio. They are also pretty easy to find where I live. When I first started using them they had a combination Philips/Square driver that came with the box of screws and actually outlived the number of screws in the box. They worked pretty good as long as you kept the drill motor inline with the screw. They would spin out from time to time and when they did it was best to back it out and try again with a new screw. Now they have changed to a Torques-Drive similar to lots of others. They are nice as you can stick the screw to the driver and it will hang on freeing up a hand. These drivers I find wear out faster, but I can grind the end flat just a little and they start working again (one time).



I remember when Hurricane Andrew hit in 1992 I couldn’t help but notice a lot of the owner built homes built in the 50’s from blocks and stick framed roofs made it thru pretty good just needing new shingles. On the other hand the places built in the 80’s with trusses and that mass production mentality of that time period just blew apart. Nail guns and plywood are great but I often see a whole row of nails missing a truss. My dad used to say a guy driving a nail will put every one in at a slightly different angle whereas a nail gun they are all parallel and can pull out together. Same with those plates on trusses. When we built my nephews pole barn we built our own trusses and cut plywood gussets and glued and nailed them on both sides. I swear they are 10X stronger than the store bought 2x4 jobs.



I had the Amish put a metal roof on our home a few years back. our place was built circa 1880. so the roof framing is 3x8 or 4x8 with full 1” thick planking. The Amish nailed purlins 2x4 laying flat to cause an air space all across the roof and the edges to screw the steel to. They tried to hit rafters where ever they could and they used long spikes. A lot of the nails came thru the sheeting though and I did go in the attic after they were done and clinch them over. I think it would take a lot of wind to pull that roof off.

 

[PJB12]

"My dad used to say a guy driving a nail will put every one in at a slightly different angle whereas a nail gun they are all parallel and can pull out together."
Your father's observation is brilliant! I'll remember that one.