Security Self Tapping Screws - Resistorx Countersunk

About our Countersunk Self Tapping Screws

Countersunk heads are a type of Self-Tapping Screw used when a flush finish is required; no part of the screw head is left protruding above the level of the item being secured. 

Torx drives feature a six-pointed star-shaped (giving them the alternate name of Star drives) recess with rounded points on the star while Countersunk bolts are used when a flush finish is required, with no part of the screw head protruding above the level of the item being secured.

Like the Pozidrive, the main reason for the development of torx drive was the ability to impart increased torque loads on the head without the fear of the tool slipping. Another beneficial feature of the torx drive is that less effort is required by the operator, as the transfer of torque is more efficient. Torx drive recesses are commonly used in the automotive industry for this reason.

Our Countersunk Self-Tapping Screws all have a pin located in the middle of the drive to prevent removal with standard tools, making them an excellent choice of Tamper-Proof Screws.

The finish on our Countersunk Screws is stainless steel and they come in a choice of Pin Hexagon or Pin Resistorx 6 lobe drive.

Why use Self-Tapping Screws?

Self-Tapping Screws, usually referred to as Self-Tappers, are screws for use when fastening to metal or plastic. The main differentiator of Self-Tappers is that they eliminate the need for pre-drilling a hole as a separate operation.


All that is required to insert a Self-Tapper is a pilot or punched hole to introduce the screw. They then form their own thread as the screw is driven into position. Once inserted, Self-Tapping Screws may be removed and re-used.

Why use Security Screws?

Security Screws are machine bolts that are generally used to deter removal (often for safety purposes) or to prevent theft. They are commonly found in public conveniences, schools, prisons; on cars, boats, public transport; and in electrical items.

We stock a Security Bit Set that covers all the popular Security Screw head types.

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