Last updated: September 3, 2021

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We most often use sheet metal screws on sheet metal surfaces and similar materials. They are also used in roofing and the installation of metal and PVC windows. These screws can be applied over an existing hole or require prior use of the drill.

Buying sheet metal screws online allows you to choose exactly the size you need. That way, you don't bother your hardware store owner by asking them for this and that screw while showing the size with your fingers. Once you have the right information, you can get any type of sheet metal screw online. If you're missing this information, don't worry: it's all in our article below.

Key Facts

  • Sheet metal screws are generally used in roofing and as a clamping element for air conditioning units.
  • If you're unsure of what you need, choose a set of sheet metal screws with various sizes.
  • You will have to evaluate various criteria before making your purchase. These include size, head shape, and drive, or whether you need to drill the plate or not.

Our Selection: The Best Sheet Metal Screws

In the following section, you will discover our selection of the best sheet metal screws currently available on the market. They are either available in different sizes or as bulk packages that contain single size screws, which are more suitable for construction professionals. That being said, please note that our list is more tailored to DIY lovers.

Shopping Guide: Everything You Should Know About Sheet Metal Screws

Sheet metal screws are a fundamental element in the fastening of all types of equipment, such as air conditioning units. Their gripping capacity and durability make them indispensable within the automotive and mechanical fields in general. In the section below, we have answered the most frequently asked questions about these screws to help you find the best products for your needs.

Sheet metals screws can vary according to the type of head, the type of thread, and the finish.
(Source: Sergey Kovtunenko: 64721508/

What are sheet metal screws exactly?

This is the name given to the screws we generally use to join metal sheets and other similar materials. The other two types of screws that exist are the wood screw (you will guess what it is for) and the metric thread screw, which has no tip and is held in place with a nut. The sheet metal screw, on the other hand, doesn't need a nut.

You can also find self-drilling sheet metal screws, which make their way into metal sheets thanks to their bit-shaped tips. This type of screw is widely used in roofing, PVC or aluminum windows, and metal constructions in general. Sheet metal screws are regulated according to the standard ANSI/ASME B18.6.4.

What are the uses of sheet metal screws?

When you choose a screw, it is essential that you take into account the type of material on which it will be applied. In that regard, its resistance needs to be adapted to its function. As we mentioned earlier, sheet metal screws are widely used in roofing, for holding air conditioning units and other similar applications. Here are some examples:

  • Supports and fixings
  • Iron fittings
  • Metal profiles
  • Joining metal sheets
  • Joining metal and wood sheets
  • Metallic doors
  • Garage doors
  • Automobile
  • Covers
  • Facades

Are these screws also suitable for wood?

The answer is ambiguous: yes and no. This is a very common question that people themselves when they are not construction professionals or DIY experts. In theory, it is always best to use the most suitable type of screw for each material. As their name indicates, sheet metal screws are specially designed for metal sheets.

However, this doesn't mean that you can't use these screws to join a metal sheet to a wooden one. Note that sheet metal screws are not recommended on materials such as chipboard. In that regard, it really all comes down to the consistency of the wood. Wooden screws have a different, wider thread that allows a better grip on this type of material.

Sheet metal screws have a fine thread, ideal for drilling metal sheets.
(Source: dolgachov: 98852658/

How do screw sizes differ?

Just like any other type of screw, sheet metal ones vary according to the type of head, the type of thread, and the finish. The kind of head you choose, for instance, will depend on whether you want the screw to protrude or whether you prefer it to be level with the surface. Here is a list with some of the types of sheet metal screw heads:

  • Round
  • Countersunk (the head is level with the surface)
  • Hexagonal

The fine thread of sheet metal screws is ideal for drilling metal sheets. Other screws that are not technically sheet metal threads are also often used on the same type of material. Self-drilling screws, for instance, feature a drill bit-shaped tip.

  • Self-tapping screws. They are applied to a pilot hole.
  • Self-drilling screws. As the name suggests, they make the hole themselves.
  • Finish. The most common finishes for screws are zinc and bichromate. The latter is used for wood screws, which have a yellow or gold color.

Each screw has its own name and a number indicating its size.
(Source: fabiol: 3572190/

Which size screw do I need for my metal sheets?

As you can see in our product selection above, you can easily find a wide array of sheet metal screw sizes to satisfy your every need. However, you can also buy a pack with all screws in a specific size if this is what you need. In that case, the first thing you have to do is measure the thickness of your metal sheets. The table below will help you choose the screws accordingly:

Screw size Diameter (inches) Sheet thickness (mm)
#2 0.086 Up to 1.50 mm
#4 0.112 Up to 2.50 mm
#6 0.138 Up to 6 mm
#7 0.155 Up to 6 mm
#8 0.165 Up to 6 mm
#10 0.191 Up to 10 mm
#12 0.218 Up to 10 mm
#14 0.251 Up to 10 mm

What material are these screws made from?

Various types of steel are used to manufacture sheet metal screws. The material undergoes a heat treatment to reinforce the structure and hardness of the screw. Stainless steel is divided into two main categories: A2 and A4.

  • A2 steel. This type of stainless steel is found in many tools. Its technical denomination is AISI 304, and it is often called SAE 304 stainless steel.
  • A4 steel. Sheet metal screws made from this type of steel are the most resistant to corrosion, as the alloy has a higher percentage of molybdenum. Its technical denomination is AISI 316, and it is sometimes referred to as marine grade steel.

How should I use sheet metal screws?

As we briefly mentioned earlier, these screws can be applied in two different ways: either on an existing hole or by means of a self-drilling screw. In the first case, marking the brass with a tiny hole is sometimes enough, and you won't need to drill. In the second case, you will use self-drilling screws with drill bit-shaped tips.

If you do need to drill the hole, the biggest mistake you can make is to use the wrong drill bit. Remember that the size of the later must be smaller than the diameter of your sheet metal screw. If you are using a 3/16" screw, opt for a drill bit with a diameter of 0.1575 or 0.1660 inches. If you get it wrong, you can try to fix it with a nylon plug.

We encourage you to buy a box of sheet metal screws that includes an assortment of different sizes.
(Source: saulhm: 106359/

What other names are given to sheet metal screws?

When you decide to explore the Internet for some sheet metal screws, you may realize that various names are used interchangeably for this type of tool. Besides, some varieties that are not technically sheet metal screws can fulfill the same function. Here are some examples:

  • P-K screws
  • Carriage bolts
  • Thread-forming screws
  • Self-tapping screws
  • Self-drilling screws

Shopping Criteria

Buying a screw isn't the challenge it once was. Before, it was normal to ask the hardware store employees and test their patience. Nowadays, you can buy a box of sheet metal screws without moving from your seat. Since you have to do so without the advice of a professional, you need to make sure you are informed about specific criteria before making your purchase. We have detailed these aspects in the following section:

Screw Size

We know many people go to their hardware store and ask for a certain size of screw using their fingers. We also know that this method isn't very efficient. Measurements were invented for this specific purpose, and online shopping allows you to find all this information about your products. Like any other tool, your sheet metal screws should be the adequate thickness and length for your needs.

If you don't know how to measure a screw, keep in mind that the length reference goes from the tip to the bottom of the head, which protrudes from the surface. On the other hand, countersunk screws are level with the surface, which is why the head is included in the measurement. Remember that the size can be expressed in inches or millimeters.

The thickness and hardness of the materials determine which sheet metal screws you need.
(Source: padrinan: 3156842/

Screw Material

As you know, screws can be manufactured with different varieties of stainless steel. As far as sheet metal screws are concerned, the differences lie in the type of alloy used and the heat treatment process. We have already discussed the two basic types of stainless steel available.

The most affordable is the A2 or AISI 304 steel, while the most rust-resistant is the A4 stainless steel – also known as AISI 316. This improved capacity against the effects of corrosion makes these screws particularly useful to fix surfaces that are continuously exposed to water, such as roof coverings.

Standard or Self-Drilling Screws

If the surface you want to apply the sheet metal screw on already has a hole perforated, all you have to do is choose a screw with the right diameter and length. If you need to drill the material, on the other hand, you can opt for self-drilling sheet metal screws. That way, you won't need a drill for the hole.

Self-drilling screws can be applied to different surfaces. Purists claim that self-drilling screws are not technically sheet metal screws. That being said, you will find self-drilling screws designed for metal sheets if you search online. They are sometimes called TEK screws or drill point screws.

Material of the Surface

The thickness and hardness of the materials determine which sheet metal screws you need. In most cases, you will be looking for screws to apply to metal sheets. While it is true that you can use them for wood (except for chipboard), we recommend you use the most appropriate screws for each surface.

Another critical aspect to consider is the weight that each screw can support. Keep in mind that sheet metal screws are widely used as fasteners for air conditioning units and other similar masses. The manufacturers generally indicate the resistance of their products on the packaging or their website.

Number of Screws

Before you make your purchase, make sure to have an idea of how many sheet metal screws you need. If you are a DIY lover, you will most likely want to opt for screws of various thicknesses and diameters. If that's the case, we recommend you buy a box with an assortment of screws of different sizes.

As we said, the products in our selection are tailored to the average home DIYer. If you work in construction, on the other hand, buying in quantity is essential. In that case, you might prefer choosing bulk packs with a single size of sheet metal screws.


If you are missing screws, you no longer need to test the knowledge – and patience – of your local hardware store clerk in search of the perfect size. Every screw has a specific name and a number that indicates its size. Now that you have read our article, you should know everything you need to purchase sheet metal screws.

User opinions on this type of product are few and far between. Keep in mind the criteria we detailed above and remember that it is absolutely necessary to read the technical specifications on length, diameter, and rust resistance carefully. What's more, you can do all of this from the comfort of your own home.

If you liked our shopping guide on sheet metal screws, feel free to leave us a comment in the section below. You can also share this article on your social media!

(Source of featured image: Alicja: 3673214/