Thread Forming Screws | Associated Fastening Products, Inc.

Thread forming screws are a special type of fastener that create threads in a mating material as they are screwed in. They do not require threaded holes, and most have sharp tips that can be screwed directly into the mating material without pre-drilling. A variety of types of thread forming screws are available for use with different types of materials including thick or thin sheet metal as well as vinyl and other polymers.

At Associated Fastening, our engineering and product design teams have been developing fastening solutions for over 35 years. We carry an extensive line of thread forming screws, as well as washers, bolts, brass fittings, and other specialized fasteners.

Learn more about thread forming screws, how they can be used, and some of their key advantages.

Material Considerations for Thread Forming Screws

Instead of cutting into the material, thread forming screws displace it, pushing the material out of the way and creating internal threads in the material. For this reason, they must be made from materials hard enough to displace the mating material without breaking or failing. The pitch, thread angle, and major and minor diameters of the screw affect the relative ease of driving it into the material. It’s also important to consider the torque required to drive the screw and the total torque along the screw’s length as it moves deeper into the material. The screw must be strong enough to withstand these forces. Coatings or lubricants can assist with installation; however, if the screw installs too easily it may not have sufficient holding power for a reliable joint.

A best practice is to use a screw that is stronger or harder than the mating material so it can tap and deform it without excessive force or stress. The relative plasticity or softness of the mating material is also important. If the material is too brittle, it could break or crack; however, if it is too soft, it may not have adequate mechanical strength to support the load in the joint. It’s also imperative to have a solid good grip between the screw and mating material for a snug fit without any “play” or loosening due to vibration.

The team at Associated Fastening can help you choose the right fasteners for your application and the mating material being fastened.

Types of Thread Forming Screws

There are different types of thread forming screws for different applications and mating materials. Some common types are explained below:

Thread Forming Screws for Plastic

Plastics are relatively pliable and soft; however, if they are too brittle or soft, they can fracture or develop shavings under pressure. Different types of thread forming screws are made that can accommodate the range of strengths and hardnesses of both thermoset and thermoplastic polymers.

Choosing a thread forming screw for plastics saves time by eliminating tapping. This further limits the amount of wear and stress to the plastic, since the screw is installed directly without additional drilling or abrasion.

Thread Forming Screws for Thin Steel

These screws have a sharp point that is easy to align with a hole or point on the material. Assemblers can quickly align with a hole in the thin steel face. Wide-spaced threads drive into the metal and create a secure joint. Thin sheets of steel or other metals are generally used for lighter loads.

Thread Forming Screws for Heavy Steel

Thick steel sheet metal, with thicknesses up to about twice the diameter of the screw, requires screws with hardened threads in order to displace the material and create inner threads. These thread forming screws are similar to coarse threaded bolts with a machine screw pitch. This facilitates installation with low driving torque and high stripping torque.

Thread Forming Screws for Lightweight Alloys

Lightweight components made from alloys of aluminum and magnesium call for screws hard enough to pierce the material without damaging the surrounding area. The ratio of thread pitch and screw diameter creates a particular geometry that grips the material and lowers the risk of the screw being pulled out or tearing the metal.

Advantages of Thread Forming Screws

Using thread forming screws instead of conventional fasteners offers several advantages, such as:

Rather than cutting into the mating material, thread forming screws displace it, so no material is actually removed from the component.
There is no need for thread tapping or pre-drilling.
Thread forming screws create their own threaded cavity in the mating material, eliminating inner threads; therefore, there is no need to check inner thread tolerances.
They are cost-effective because they save time and labor at installation.
Thread forming screw heads can be manufactured to match colors for assemblies with a clean and finished look.

Contact Associated Fastening for Thread Forming Screws

Thread forming screws make high-quality production and assembly fast and reliable. Associated Fastening provides high-quality screws, bolts, nuts, washers, O-rings, and other fasteners to OEMs and their suppliers. We also offer CNC machining, laser and water jet cutting, metal stamping, packaging, and vendor managed inventory services.