A Comprehensive Guide to Self Tapping Vs Self Drilling Screws
- Self-drilling Screws, Self-tapping Screws
In this educational guide, we’re shining the spotlight on two highly-utilized but often confused screw types: self tapping vs self drilling screws. On the surface, these screws may bear a close resemblance, but their differences become apparent when you dive into their unique characteristics and applications.
Table of Contents
What are self tapping screws?
Self tapping screws are a type of screw that can create their own threads as they are driven into a material. This makes them ideal for use in materials that are difficult to tap, such as metal, plastic, and wood. Self tapping screws are available in a variety of sizes and head types, and they are used in a wide range of applications, from construction to electronics.
Comprehensive Guide to Self Tapping Vs Self Drilling Screws
Self tapping screws, as their name suggests, have the unique ability to form their own threads as they are driven into material. This attribute significantly simplifies the assembly process, making self-tapping screws a go-to choice for various applications, especially when dealing with thin metal, wood, or plastic.
Let’s dig deeper into the characteristics, types, and uses of self-tapping screws:
Self-tapping screws are designed to drill their own hole as they’re screwed into material. They cut a path and create a fitting thread, saving you time and effort by removing the need for a pre-drilled hole.
The Two Types of Self-Tapping Screws Thread Forming and Thread Cutting Screws)
These two types are very different and making sure that you have chosen the correct type of thread design for your application is vital. In these sections we will explore the advantages and applications of the two types of screws.
Thread-Forming Screws Advantages
- Less Material Damage – Thread-forming screws create threads by displacing the material rather than cutting it away. This results in less material damage, particularly in softer materials like plastic.
- High Resistance to Loosening – The tight fit between the screw and the material can result in a higher resistance to loosening caused by vibration or load changes.
- No Material Debris – Since thread-forming screws do not cut away material, there is no concern about debris within the application.
- Improved Sealing – They provide a better seal against liquids and gasses in the hole due to the close contact between the screw and the material.
Thread-Forming Screws Applications
- Thread-forming screws are typically used with plastic due to the material’s ability to deform and recover.
- Soft Metals They can also be used with certain types of soft metals that can be easily displaced.
- Electronics Thread-forming screws are often used in the assembly of electronic devices, where plastic casings and parts are common.
Thread-Cutting Screw Advantages
- Easier Drive-In – Thread-cutting screws are easier to drive into harder materials due to the cutting action of the threads.
- Strong Hold – They provide a strong hold in the material because the threads are cut into the material rather than being formed by displacement.
- Suitable for Thick Materials – These screws work well with thicker and denser materials where displacement isn’t an effective option.
Thread-Cutting Screw Applications
- Metal – Thread-cutting screws are commonly used with metal because the screw can cut its own threads into the material.
- Hard Plastics & Dense Materials – They are also suitable for hard plastics and other dense materials that can withstand the cutting action of the screw.
- Construction – Often used in construction applications due to their strong hold in a variety of materials.
Common Types of Self-Tapping Screws
There are various types of self-tapping screws designed for specific applications. Some of the most common include:
- Sheet Metal Screws – Used primarily for attaching metal to metal or metal to wood. They have a sharp, pointed end and are available in a variety of head styles.
- Wood Screws – Although designed for wood applications, these are self-tapping and often used when attaching wooden parts to metal.
- Drywall Screws – Designed specifically for drywall applications. These screws have a bugle head to prevent tearing of the drywall paper.
- Pan Head Screws – Named for their flat, rounded top. These are commonly used in appliances and electronics.
- Hex Washer Head Screws -Recognized by the built-in washer under the head, these screws offer a large bearing surface and are used frequently in construction projects.
Most Common Industries and Applications for Self-Tapping Screws
Self-tapping screws are widely used across numerous industries and applications, owing to their unique ability to form their own thread. Here are some of the most common:
- Construction – Used in various tasks such as installing drywall, assembling frameworks, or fastening metal to metal.
- Automotive – Utilized extensively in car manufacturing and repair, including bodywork and interior fittings.
- Electronics – Used to fasten components together in devices such as computers, televisions, and other electronics.
- Furniture Assembly – Commonly used in assembling furniture due to their ability to securely fasten wood or metal.
- Appliances – Used in the assembly and repair of household appliances like refrigerators, washing machines, and air conditioners.
Guide to Self-Drilling Screws
What are self drilling screws?
Self-drilling screws are a type of screw that can drill its own hole as it is driven into the material. This eliminates the need to pre-drill a pilot hole, saving time and effort. Self-drilling screws are available in a variety of sizes and head types, and they are used in a wide range of applications, including construction, roofing, and metal fabrication.
Unlike regular screws that require a pre-drilled hole to be inserted, self-drilling screws feature a drill bit-shaped point that cuts through material as the screw is driven. This allows the screw to drill its own hole and subsequently form threads, reducing the number of steps required in the assembly process.
Self-drilling screws are most often used in applications involving metal. Some typical applications include:
- Metal roofing and cladding
- Steel framing
- HVAC system ducts clips & brackets
- General construction projects
Self-drilling screws come with several advantages. Their all-in-one design can significantly speed up assembly processes, reduce labor costs, and decrease the chance of misalignment caused by separate drilling and screwing processes. However, they also come with some disadvantages. For example, they can be more expensive than standard screws, and their drill bit tips can sometimes be fragile and prone to breakage, especially when used in harder materials.
Self Drilling Screws Key Points:
- Self-drilling screws are capable of both creating their own holes and forming threads in one action due to their drill-bit-like point.
- Both self-drilling and self-tapping screws can technically tap threads, though self-drilling screws also possess the ability to drill their own holes.
- Self-drilling screws can be classified into fine or coarse threads.
- Self-drilling screws’ drill point sizes, which are commonly #2, #3, #4 and #5 (Series 500), dictate their drilling capacity.
- Sizes #2 and #3 are most common, while sizes #4 and #5 are used for thicker metal.
Self Tapping vs Self Drilling Screws: The Key Differences
When comparing self-tapping and self-drilling screws, several key differences come into play. Self-tapping screws create their own threads, while self-drilling screws not only form threads but also drill their own holes. While self-tapping screws are more versatile, capable of being used in a range of materials including plastic, metal, and wood, self-drilling screws are typically used in metal applications.
There are certain situations where one type of screw is preferable over the other.
- For thin or soft materials, self-tapping screws are often the better choice as they’re less likely to cause material damage.
- For thicker or harder materials, especially metals, self-drilling screws can speed up the installation process as they eliminate the need for a separate drilling step.
The American National Standards Institute (ANSI), provides a list of the standards relating to self tapping screws that you can reference.
