Самонарезающие и самосверлящие винты: в чем реальная разница?

In the commercial construction and metal building industries, the terms self-tapping screws and self-drilling screws are frequently used interchangeably. However, misinterpreting the technical difference between these two fasteners can result in damaged substrates, stripped screws, or costly onsite delays.

To establish the foundational rule utilized by global engineering standards (including ISO and ASME):

The Golden Rule: All self-drilling screws are self-tapping, but not all self-tapping screws are self-drilling.

Here is an industry-grade breakdown of self-tapping vs. self-drilling screws, their point mechanics, and how to choose the right fastener for your structural project.

Defining the Fasteners: Tip Design & Mechanics

What are Self-Tapping Screws? (Often called Tapping or Sheet Metal Screws)

Self-tapping screws are engineered with a sharp, pointed (Type A/AB) or blunt (Type B/F) tip. Their primary function is to “tap” (cut or form) mating threads inside an existing hole.

The Catch: They cannot drill through heavy structural raw metal on their own. They require a pre-drilled or pre-punched pilot hole of a precise diameter. As the screw is driven in, it displaces or cuts material to create a high-retention, vibrations-resistant grip.

What are Self-Drilling Screws? (Widely known as Tek Screws)

Self-drilling screws are a highly specialized subset of self-tapping screws. They are instantly recognizable by their drill bit-shaped tip (ranging from Point 2 to Point 5).

• The Advantage: They do not require a pilot hole. In a single, continuous operation, the drill point bores the starter hole, and the trailing threads immediately follow to tap and secure the connection.

Side-by-Side Comparison: Self-Tapping vs. Self-Drilling

Application Guide: When to Spec Self-Tapping vs. Self-Drilling

When to Specify SCREWTRADE TIMBER-Tite Self-Tapping Screws:

1.Thin-Gauge Material Stitching: When fastening ultra-thin sheet metal where a drill tip might over-enlarge or “strip out” the hole during the drilling phase, a self-tapping screw with a pre-drilled pilot hole offers superior clamping force.

2.Maintenance and Retrofitting: Ideal for replacing existing fasteners in pre-engineered frames where matching pilot holes already exist.

3.Softer Substrates: Excellent for fastening metal components to plastics, composites, or treated timber.

When to Specify SCREWTRADE METAL-Tite Self-Drilling Screws:

Metal Roofing & Siding Installation: The absolute industry standard for securing corrugated roof panels, standing seam clips, and siding to steel purlins.

Thick Structural Steel Penetration: For applications involving heavy steel framing or rigid H-sections. BDN’s Point #5 heavy-duty drill points can penetrate up to 1/2” (12.5mm) structural steel without pre-drilling.

High-Volume Commercial Projects: When labor costs and speed are critical. Eliminating the pre-drilling step cuts installation time by up to 50%, significantly reducing onsite tool wear.

Why Choose SCREWTRADE Fasteners for Your Metal Construction Needs?

Whether your blueprints call for high-performance thread-cutting self-tappers or high-speed structural self-drillers, SCREWTRADE Fasteners manufactures products compliant with rigorous global standards (including AS3566 Class 3/4 corrosion resistance). Our METAL-Tite series features proprietary surface coatings engineered to prevent galvanic corrosion and red rust in the harshest environments.

What’s the Difference Between Self-Drilling and Self-Tapping Screws?

Despite their widespread availability and usage in commercial, industrial, and construction applications, many still confuse self-tapping screws with self-drilling screws.

Part of the reason this happens is that self-drilling screws are a subtype of self-tapping screws.

Let’s go through these two products separately to clarify these differences.

Self-Tapping Screws

Self-tapping screws have various names. They’re often called metal screws, sheet metal screws, tapping screws, or tapper screws.

Their tips come in different shapes: pointed (like a pencil), blunt, or flat, and they are described as thread-forming, thread-cutting, or thread rolling. If the screw is pointed, it will be thread-cutting – tapping and creating threads in a pre-drilled hole. If the tip is flat, it is thread-rolling – rolling or extruding threads and creating zero clearance between screw and material.

When it comes to selecting the right self-tapping screw, it’s important to consider the material the screw will be used on. Different types of self-tapping screws are designed for specific materials such as wood, metal, or plastic. The size and length of the screw should also be considered, as well as the desired level of torque, or tightening force, required for the application.

Self-tapping screws are generally easy to install and can be used with a variety of tools, including power drills and screwdrivers. However, it’s important to note that over-tightening can cause the screw to strip the threads, reducing its holding power. It’s also important to ensure that the pilot hole, or hole that the screw is inserted into, is the correct size and shape to ensure proper thread formation and holding power.

The most important difference between self-tapping and self-drilling screws is that self-tapping screws cannot go through metal without a pilot hole, which must be pre-drilled or pre-punched.

One of the main advantages of self-tapping screws is that they do not require pre-tapping, which is the process of creating threads in the material before inserting the screw. This eliminates the need for additional tools and can save time and labor costs. Additionally, self-tapping screws can be used in materials that are too thin or brittle to be pre-tapped, making them a versatile choice for a wide range of applications.

Exact drill or punch hole size is also important. If the hole is too big, the screw will become loose and not thread properly and securely into the hole. If the hole’s too small, the screw can break or cause the material to split or crack.

Self-tapping screws are good for use with metals, various types of plastics (plywood, fiberglass, polycarbonates), and cast or forged material, like iron, aluminum, brass, bronze. Self-tapping screws also work for surfaces where you can’t secure the rear end with a nut. Common applications include fastening aluminum sections, attaching metal brackets onto wood, or inserting screws into plastic housings.

In conclusion, self-tapping screws are a versatile and convenient option for creating threads in a variety of materials. They are easy to install and can save time and labor costs, making them a popular choice for many applications. By considering the material, size, length, and thread pattern of the screw, and by following proper installation techniques, you can ensure that your self-tapping screws will provide a secure and reliable hold.

Self-Drilling Screws

Self-drilling screws are easy to distinguish if you look at their point, which curves gently at the end and is shaped like a twist drill. They’re often called Tek Screws, after the brand name that popularized them.

Self-drilling screws are generally easy to install and can be used with a variety of tools, including power drills and screwdrivers. However, it’s important to note that over-tightening can cause the screw to strip the threads, reducing its holding power. It’s also important to ensure that the pilot hole, or hole that the screw is inserted into, is the correct size and shape to ensure proper thread formation and holding power.

Screw lengths vary, but drill points are standardized, identifiable by number (1 to 5), which determines their length and thickness. Head and drive styles vary; self-drilling screws are most commonly hex, Phillips, or square.

Unlike self-tapping screws, self-drilling screws need no pilot hole to cut and fasten; they can drill, tap, and fasten in one go, which saves you the extra step of drilling, then fastening.

When it comes to selecting the right self-drilling screw, it’s important to consider the material the screw will be used on, such as wood, metal, or plastic. The size and length of the screw should also be considered, as well as the desired level of torque, or tightening force required for the application.

Another important factor to consider when using self-drilling screws is the tip of the screw. Self-drilling screws come in a variety of tip styles, such as a fluted, split-point screw to encourage chip removal. The different tip styles are designed to help guide the screw through the material and prevent tip overheating, which can lead to a poorly formed hole or damaged material.

These screws can fasten metal to metal, wood to metal, and work well with light, self-tapping screws. They are good for metal building and light gauge metal assemblies; Point #5 is already capable of fastening half-inch steel sheets. Self-drilling screws are useful in HVAC applications, cladding, metal roofing, steel framing, and general construction tasks.

In conclusion, self-drilling screws are a versatile and convenient option for creating threads and drilling hole in a single step. They are easy to install and can save time and labor costs, making them a popular choice for many applications. By considering the material, size, length, and tip of the screw, and by following proper installation techniques, you can ensure that your self-drilling screws will provide a secure and reliable hold.

Similarities and Differences

What’s most similar about these two types of screws is that both form theads as they penetrate the material being worked with. Both attach steel on steel and steel on wood when rivets or nuts and bolts cannot do the job.

The main advantage with self-drilling screws over self-tapping screws is two instant advantages: time and costs saved at assembly time, no mistakes of drilling, which often happens if one pre-drills holes in the wrong size.

Consult with self-drilling screw manufacturers you can trust – contact Screwtrade Fasteners today.

Explore Our Full Range of Screwtrade Self Drilling Screws Here