Drywall screws are available in 6 and 8 diameters and in several lengths ranging from just over 1 inch to 4 inches. The screws have a black phosphate coating to help resist corrosion. However, this coating won't prevent the screw from rusting if used in wet environments or for exterior applications.
The same applies to standard wood screws. A wood screw is used to secure one piece of wood to another. It can also be used to attach hinges, handles, locks, and other hardware to wood.
A conventional wood screw has a tapered body and coarse threads with the upper portion of the shank unthreaded. The unthreaded portion improves the ability of the screw to pull mating pieces of wood together. Some newer wood screw designs have a fully threaded shank, allowing them to be installed without a pilot hole if the wood is not too hard.
A pilot hole is often required when installing a wood screw, especially if the wood is very hard or susceptible to splitting. Woods such as oak, cherry, and maple require a pilot hole. A wood screw with a flat head is countersunk to be flush with or below the wood surface.
A raised head screw is countersunk with a slight dome head projecting above the surface. But more importantly, drywall screws can snap off if subjected to excessive stress in use. But what exactly is excessive stress? To help answer this question, I decided to run a few highly scientific tests in the woodshop.
I clamped the assembled boards to the workbench with the piece receiving the screw projecting over the edge of the bench. Then the fun began. I grabbed my trusty 8 lb sledgehammer and proceed to whale away on the projecting piece. This was a clean break in that there was minimal splintering of the wood.
I then ran the sledgehammer test on two pieces of wood held together with wood screws. This time, the joint also failed after about blows but the screws did not snap; instead, they bent and pulled loose from the wood after the wood splintered around the screws.
In other words, the wood failed before the screws did. So, what was learned from this little experiment other than to not beat on furniture with a sledgehammer? In normal use, the average piece of furniture would not be subject to this kind of concentrated punishment.
But if a joint is exposed to continuous stress over time, perhaps due to racking or moisture-related movement, the stress would impart lateral forces on the fasteners.
Based on the results from this experiment, I would be leery of using drywall screws in such applications for fear the screws would fail. One downside of the coarse-thread screws: the metal burrs that can embed in your fingers.
Be sure to wear gloves when working with coarse-thread drywall screws. Fine Thread Drywall Screws. Fine-thread drywall screws are self-threading, so they work well for metal studs. Fine-thread drywall screws are best for installing drywall to metal studs. Coarse threads have a tendency to chew through the metal, never gaining proper traction.
Fine threads work well with metal because they are self-threading. Fine-thread drywall screws do not hold as well in wood as do coarse-thread screws. Gauge refers to the diameter of the drywall screw. In most cases, you will be using either 6 or 8 drywall screws.
Keep in mind that as gauge numbers increase, the screw becomes larger in diameter. So, a 6 drywall screw would be thinner than a 8 drywall screw. While this may seem evident, many materials related to home construction work in the opposite direction. For example, smaller number sandpaper grits are actually coarser than grits with higher numbers. Actual sizes of drywall screw gauges:.
Gauge is often expressed as the second number after the length. The main purpose for drywall screws is securing full sheets of drywall usually 4-foot by 8-foot for do-it-yourselfers or partial sheets of drywall to either wood or metal studs. Drywall screws are good for repairing nail pops. If you have an older house and find walls that have mysterious circular bumps , then you have what are called nail-pops.
Before drywall screws came into widespread use, drywall was nailed into place with short, wide-head nails. While drywall nails are still around and do have their use as a quick way to fasten wallboard, drywall screws have evolved as the standard method of attaching drywall to studs precisely because of the nail-pop problem.
Some do-it-yourselfers use drywall screws for one unintended purpose: building projects. Drywall screws tend to be brittle. Rather than bending, they can snap. Drywall screw heads are especially prone to cleanly breaking off, leaving the shaft section embedded in your wood. No screw extractor can remove a headless screw. Few woodworkers would ever use drywall screws for fine building. Avoidance of drywall screws is especially important with heavy or even moderate building tasks, critically with outdoor projects like fences and decks.
But drywall screws can be used for light building projects or for temporary construction when safety is not a factor.
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