As most DIY enthusiasts can tell you, having the right tools and accessories is critical for best results. Screws come in many shapes and sizes, depending on the job for which they are intended. Consequently, this begs the question: do you need special screws for metal?
You need special screws specifically designed to fasten metal to various objects. Metal screws have certain design elements, such as fully-threaded shanks and self-tapping capabilities that make them specially suited for attaching metal pieces to one another or other types of materials.
Read on to learn more about metal screws and all other relevant information on the subject.
What Are Metal Screws?
As their name suggests, metal screws are designed for the purpose of fastening metallic objects.
They can attach metal to metal, or metal to other types of materials, such as wood, plastic, or fiberglass.
The key takeaway here is that if your project involves fastening metal, you will always need metal screws.
At first glance, metal screws resemble other types of screws.
However, they have a few key characteristics that make them ideal for driving into and securing metal objects.
Threading is the first and most significant feature that sets metal screws apart from the rest.
Threads refer to the furrows or lines that run along the body of the screw.
Metal screws typically feature full threading, as it allows them to have a firmer grip. Conversely, wood screws have partial threading on their shanks.
In addition to having fully-threaded shanks, you will also notice that the threading in metal screws tends to be much narrower than in other types of screws, i.e., more grooves per inch (2.54 cm).
Again, this design feature allows metal screws to have a strong grip, which is necessary when fastening metal.
Another design feature that is inherent to metal screws is the ability to self-tap or self-drill. Let’s take a quick look at what these terms mean.
Self-Tapping vs. Self-Drilling Metal Screws
Metal screws are sometimes referred to as self-tapping or self-drilling screws.
Since metal is a tough material, the tip of a metal screw needs to be designed in such a way that it can penetrate the surface without a lot of hassle.
Self-tapping metal screws have especially sharp and pointed tips.
These tips help them burrow more easily into strong pieces of metal.
They also help them create their own threads.
However, self-tapping screws are only applicable where a pilot hole is pre-installed.
This is because the sharp tips of self-tapping screws don’t have the structural integrity required to create their own holes.
Self-drilling metal screws are what you go for if your sheet metal doesn’t have pre-drilled holes.
As their name implies, self-drilling screws “drill” their own way through metal.
They don’t require you to tap them or drill a hole for them first.
This allows them to penetrate, make grooves, and fasten without the need for extra tools.
What Are Metal Screws Made Out Of?
As you can imagine, metal screws need to be structurally sound to be able to withstand the high amounts of pressure needed to keep metal joints intact.
There are two main types of metal screws: carbon steel and stainless steel.
Let’s take a look at each of these:
- Carbon steel screws: Tough, relatively inexpensive, and durable, carbon steel screws are the most common type of metal screws. They work best in areas that aren’t exposed to the elements, as they can be susceptible to corrosion.
- Stainless steel screws: These are the more expensive option, but they have their benefits. Because they include additional elements like chromium and nickel, they can better withstand the elements and are superior outdoor screws.
It is also important to note that there are different grades of stainless steel, with some being better than others.
These grades are determined by the amount of chromium they contain, with those having higher chromium levels being more durable, as well as more expensive.
Other materials used to make metal screws include aluminum, copper, and titanium.
Even though aluminum screws are lightweight, many people prefer them because they look nice and shiny.
Copper is renowned for being exceptionally corrosion-resistant and can withstand even the harshest weather conditions (i.e., rain, ocean spray, and snow).
Titanium screws are the most expensive type of metal screws, and with good reason – they are extremely light while being exceptionally durable.
Can You Use Wood Screws in Place of Metal Screws?
The design of wood screws makes them unsuitable for fastening metal objects.
Unlike metal screws, wood screws feature partially-threaded shanks.
As mentioned, having a fully-threaded shank is crucial for metal screws since it allows them to have a greater grip.
However, such high amounts of grip strength are not ideal for woodworking applications since they can crack the wood.
Therefore, by having fewer and wider-spaced threads along their shank, wood screws generate just the right amount of grip to hold wood pieces together without compromising the structure.
Another reason why wood screws are ill-suited for metalworking is that they are not self-tapping.
That means that they cannot create their own grooves in the metal.
Moreover, the tensile strength of wood screws is too low to support high loads.
Nevertheless, while you cannot use wood screws in place of metal screws, the same cannot be said for the latter.
If you find yourself in a bind during your woodworking project, you can always try to use metal screws as long as they fit the dimensions of your pilot hole.
You need metal screws to fasten or attach metal pieces because they’re designed for that particular purpose.
Admittedly, wood and metal screws can be difficult for the untrained eye to tell apart.
However, if the screw has a fully-threaded shank (body), it is a metal screw.
The full-thread design allows metal screws greater levels of grip.
As always, don’t hesitate to ask your hardware supplier for help if you have difficulty identifying your metal screws.
Moreover, you should also consider the particular application they’re intended for so you can choose the ideal type of metal screw for the job.
Cheers, tools owners!