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Recently I found that there're some superior nails for constructing hurricane-resistant houses - with very clever design for preventing pulling the nails out and tearing the boards off when the structure is under harsh wind load. I saw similar nails before - those were designed for flooring, but that's the first time I see nails with such advanced design.

What I don't get is why not just use wood screws? I mean wood screws are specifically designed for heavy loads - for example, for attaching door hinges - and they can be driven very fast with power drivers.

Why go to such lengths and invent those extremely advanced nails instead of using screws?

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It is all about time. In this case, the time required to drive a screw, instead of the time to drive a nail with a loaded nail gun. Drive 10 screws, and who cares if it takes a few seconds longer to drive each screw. Drive 10,000 screws, and it starts to matter.

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    @sharptooth, have you seen someone with a nail gun? If they're not doing 1 nail per second, they are lollygagging. When you need to do thousands of nails per roof, 1 second vs. 4 seconds is a huge difference. – Alex Feinman Nov 1 '10 at 13:12
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    A nail gun will drive a nail as fast as you can move the gun into place and slap it against the wood. Read my answer. Save 3 seconds per nail compared to a screw. Drive 10 nails or 10 screws, who cares? Drive 10,000 nails. This means you have saved 30,000 seconds. 30,000 seconds is 8.3 man-hours of work, a man-day! A contractor building a house has no interest in paying their crew for additional man-days of work, and to do so day after day. – user558 Nov 1 '10 at 13:19
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    Nails from a nail gun also have a much better hold than regular "hammered in" nails. The reason being that the nails in a strip are held together with glue. As the nail is forced into the wood at high speed, the glue that used to hold the nails together is melted and helps to hold the nail in the wood. Pretty ingenious really. – Eric Petroelje Nov 1 '10 at 16:38
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    @Eric - I had no idea that's why they used glue, I just figured it was cheap and easy. – Steve Jackson Nov 2 '10 at 1:55
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    @Steve Jackson: That's not all. While the glue is melted it lubricates the nail and so the nail goes in easier. Then the glue cools down and bounds to the nail and the outer material. So at different times the glue exposes two opposite behaviors. – sharptooth Nov 2 '10 at 6:12
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I have heard that wood screws take longer, which if you have used a nail gun, then you'll see the huge difference. Wood screws have their place but they are not efficient to build a home.

Considering the HurriQuake nails: It probably has not caught on yet. When I built the second room on my house, I had to use hurricane ties such as SP-1 and SP-2 with 10d and 16d nails - standard nails. These nails were driven at certain angles in order to provide strength and reinforcement. When you consider the cost of the 10d and 16d compared to the higher cost of the HurriQuake nails along with spending the money and time to update structural specifications, then you'll see why these have not caught on even though they make work better.

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Another big reason:

Screws are brittle and can't withstand the stress of a shear loaded joint, so use of nails is necessary simply because screws will fail in that application (and are required by building code).

The only proper fastener besides a nail would be a bolt - and that would take even longer (and cost far more) than driving a framing nail.

And just like woodchips said above, speed/cost is a big factor - I can drive 20 nails with my framing nailer in the time you can run a pair of 3" screws into a stud.

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    Bolts can't really take sheer either, in most applications -- they provide pressure against the materials, so the friction of the materials being joined provides the resistance against sheer. Even for nails, if you're expecting sheer loads, you want to place an adhesive down before nailing. – Joe Nov 6 '10 at 1:58
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Ever snapped every third deck screw in 1/2 with a screw gun? This shows how brittle common wood screws are - very low shear strength, so they are not efficient for resisting cyclic (repeated back and forth) loading, as is required for wind and earthquake loads. On the other hand, nails are very ductile and have a flat head which also resists pulling through the connected member (the tapered head of a wood screw will pull through when the connected member, or plywood, buckles or twists under load). By the way, nails are considered "dowel" type fasteners in wood construction - they work by bearing against the sides of the holes made through the thickness of the two wood members ... same as lag bolts and machine bolts - so bolts are very good for resisting shear, as that is their primary use. They actually do not "clamp" for friction in wood construction, since wood shrinks... thus you will lose any clamp effect (even in steel construction, special high strength bolts are required if "clamping" force is intended). And, while adhesive is excellent for increasing strength and minimizing squeaks, it is rarely factored into the strength of structural wood connections, since it is difficult to monitor the proper installation of adhesive in a construction environment (notice that floor sheathing is typically glued to joists, while "shear panel" plywood is rarely glued to the studs since you're not walking on it). Lastly, high-strength structural wood screws, with a flat head (e.g., GRK), are now available but they are extremely expensive and, as others have mentioned, time consuming to install compared to nails.

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