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Self-Tapping Metal Screw - Buying & Use Guide
Steel self-tapping screws earn their name by cutting their own thread when drilled into metal or wood substrates. As a result, the installed self-tappers yield precisely fitted threads for a particularly strong grip.
SFS commercial self-tapping screws come with diverse specifications, steel compositions, and point design, equipping them to serve varying strength, weather resistance, and material needs. However, regardless of which fastener you choose for your upcoming roofing or deck project, you can expect uncompromising product quality supported by first-rate customer service.
Explore our collection of steel self-tapping screws, discover our most popular designs, and learn more about this type of fastener.
Scroll or click below to get started
- Understanding steel self-tapping screw points from SFS
- Distinguishing our two steel options for roofing self-tapping screws
- Self-tapping screws - understanding their optimal use
- Differences between self-tapping screws and self-drilling
- Why partner with SFS for your self-tapping screw needs
- Frequently asked questions: self-tapping fasteners
Carbon steel tappers
14 Type A
- 3/8" AF Hex head
- Type A point
- Bond seal washer
- Attachment thickness: .044–.075"
- Available lengths: 3/4" - 6"
1/4-14 Type AB
- 3/8" AF Hex head
- Bond seal washer
- Attachment thickness: .044–.500"
- Available lengths: 3/4", 1", 1-1/4", 1-1/2"
17 Type AB
Strip-out Repair
- 3/8" AF Hex head
- Type AB point
- Bond seal washer
- Attachment thickness: .036–.060"
- Available lengths: 3/4", 1", 1-1/2
1/4-14 ZAC® Type 17-AB
- 3/8" AF Zinc alloy capped hex washer head
- Type 17-AB milled point
- EPDM washer
- Drilling capacity: .018–.030"
- Available lengths: 1", 1-1/2", 2", 2-1/2"
1/4-14 Type B
- 3/8" AF Hex head
- Bond seal washer
- Attachment thickness: .044–.500"
- Available lengths Type: 3/4" - 6"
#17 ZAC® Type AB
Strip-out Repair
- 3/8" AF Zinc alloy capped hex washer head
- Type AB point
- EPDM washer
- Repair fastener for stripped out #14 Type A or 1/4" AB
- Available lengths: 1", 1-1/2"
304 Stainless steel tappers
14 Type A 304SS
- 3/8" AF 304 Stainless hex head
- Type A point
- Stainless bond seal washer
- Attachment thickness: .044–.075"
- Available lengths: 3/4", 1", 1-1/4", 1-1/2", 2", 2-1/2", 3", 3-1/2", 4", 5", 6", 7", 8"
1/4-14 Type B 304SS
- 3/8" AF 304 Stainless hex head
- Type B point
- Stainless bond seal washer
- Attachment thickness: .044–.500"
- Available lengths: 3/4", 1", 1-1/2", 2", 2-1/2", 3", 3-1/2", 4", 5", 6", 7", 8"
1/4-14 Type AB 304SS
- 3/8" AF 304 Stainless hex head
- Type AB point
- Stainless bond seal washer
- Attachment thickness: .044–.500"
- Available lengths: 3/4", 1", 1-1/4", 1-1/2"
17 Type AB 304SS
Strip-out Repair
- 3/8" AF 304 Stainless hex head
- Type AB point
- Stainless bond seal washer
- Available lengths: 3/4", 1", 1-1/2"
Understanding steel self-tapping screw points from SFS
In order to better serve our customers, we offer metal self-tappers with three different types of points:
Type A - The point of this self-tapping screw is sharp enough to pierce many metal substrates as thick as 16 gauge. However, for deeper metals, a pre-created hole will be necessary.
Type AB - Though its point is not quite as sharp as type A, this self-tapping screw has the added advantage of a coarser thread profile (meaning that there is less spacing between each). As a result, they can pierce up to 12 gauge of materials.
Type B - Sharing the same threading as Type AB, this self-tapper lacks sharpness, entirely. This is best used with thicker applications and requires a pilot hole.
Distinguishing our two steel options for roofing self-tapping screws
The classification of steel offers more diversity than you may realize. Though it embodies a full range of strengths, rust resistance, and compositions, SFS chose the following steels for our roofing and cladding self-tapping screws.
Carbon Steel - Named for its significant carbon content, a carbon steel self-tapper must have 2.1% of its weight attributed to carbon. This provides greater overall strength than many stainless steels. However, its shortcoming is the lackluster rust-preventing properties. Though we utilize carbon steel with corrosion-resistant metals within its composition, it is best used in less-harsh environments.
- 304 Stainless Steel - Bring on the rain, sleet, and salty ocean air! 304 stainless steel self-tapping screws can withstand the wettest of environments. As you can learn about in our article 300 vs 400 Series Stainless Steel, 304 is amongst the most rust-resistant metals available to fastener manufacturers and their customers. In turn, it isn’t quite as strong as other steels (like 400 series or carbon), though it's hard in its own right.
Self-tapping screws - understanding their optimal use
Self-tapping screws are used for attaching metal to either metal or wood, as well as heavy plastic applications. They’re particularly practical for installations in which only one side of the substrate is reachable, such as roofing and deck projects.
However, they’re not necessarily well-suited for every construction need. For example, self-tapping screws should not be used if there is not a pre-drilled hole in both the panel and the substrate. The exception to this rule is if you attach steel panels (no thicker than 22ga) to a wood substrate while using a #14 Type A Milled Point screw.
Differences between self-tapping screws and self-drilling
Take note, self-tapping and self-drilling are not synonymous. The key differentiator is that self-drilling screws don’t require a pilot hole prior to application with their point resembling that of a drill bit. They also tend to attach thicker metals, commonly found with metal cladding or roofing.
Some self-tapping screws can pierce wood, plastic, and thinner metals. However, depending on the thickness of the metals and the type of point, a smaller hole may be necessary prior to the self-tapper application, especially when partnered with metal paneling.
Why partner with SFS for your self-tapping screw needs
We don’t design our products for amateurs—we combine cutting-edge engineering with quality steels to produce self-tappers and other fasteners that are strong and reliable enough for large-scale roofing and cladding projects. We also appreciate that time is money, and incorporate features that expedite installation while reinforcing safety.
Frequently asked questions: self-tapping fasteners
Q. Which head types are available with steel self-tapping screws?
A. Self-tapping screws cover a full range of head types. Most commonly seen are hex heads which have a flat or indented top surface, six flat sides, and a flat bearing surface built to handle rougher installation. As well as countersunk or pancake styles which lay flush with the substrate. A hex washer head has six flat sides formed integrally with a flat washer that projects beyond the sides and provides a flat bearing surface. SFS offers a Zinc alloy cap -or ZAC- a hex washer head that will never red rust.
Q. What is the difference between self-tapping screws and "normal" screws?
A. Self-tapping screws create their own threads in the substrate, unlike machine screws that require the substrate to be tapped with threads prior to installation.
Q. What's the difference between thread-forming and thread-cutting screws?
Thread-forming tapping screws displace substrate material around the threads as they do not remove material. These thread-forming screws are generally for applications in materials where large internal stresses are allowable, or desirable, to increase resistance to loosening. Thread-cutting tapping screws remove the substrate material to form threads as they are being driven. These thread-cutting screws are generally for substrates where internal stresses made by thread-forming screws would be undesirable.
Q. How strong are self-tapping screws?
A. Self-tapping screws have different strength characteristics, depending on material, diameter, and the thread profiles. Performance data for each product can be found on data sheets.
Q. What are the best drills for self-tapping screws?
A. In our Quality and Engineering departments, SFS uses both corded and cordless Dewalt drills. However, any power drill capable of holding a drill bit can be used.
Q. What is the recommended pilot hole size for self-tapping screws?
A. Pilot hole size determines installation performance and pull out strength. The hole size for self-tapping screws depends on the thickness of the materials being fastened. Drill bit size for each fastener and different substrate thickness can be found on product data sheets.
Q. What diameter self-tapping screw is best?
A. The ¼” diameter self-tapping screws are recommended for start up roofing and cladding while the larger diameter #17 self-tapping screws are used for strip out repair.
Q. Are self-tapping screws removable?
A. Yes, self-tapping screws can be removed. Please consult with SFS for recommendations on suitable replacement fasteners.
Q. Can you use self-tapping screws for steel and other metals?
A. Yes, self-tapping screws can be used with steel without hesitation. However, we advise consulting with the experts at SFS before using it with aluminum and other metals.
Q. Can self-tapping screws be used in wood?
A. Yes, our #14 Type A Milled Point and ¼ 14 ZAC Type AB screws can be used in wood and metal substrates.
Q. Can self-tapping screws be used in concrete?
A. No, only screws that are specifically designed for concrete can be used with concrete. Do we have any concrete fastener suggestions? (Deklite™ Nylon Reinforced Fiberglass Auger Dekspike™ strctural concrete roof anchor)
Q. Can self-tapping screws be reused?
A. No, it is not recommended for self-tapping screws to be reused.
Q. How will I know which washer type to pair with the self-tapping screw?A. For greater insights into selecting a washer, read Washer types: when to choose which.
