Thread Cutting Screw

The off-center shank slot on these case-hardened screws provided the first type of thread-forming fastener. The various slot designs provide true cutting action, cleanly removing the mating metal as it is installed - eliminating a separate tapping operation and generating a perfectly mated thread that contributes to a stronger fastening.

Over the years, several types of thread cutters have been designed for specific applications and materials.

• Type 1 thread cutting screws are recommended for steel parts having a thickness less than half of the screw diameter.
• The Type 23 thread cutting screw, with its wider shank slot. is recommended for use in cast iron and soft metals such as zinc and aluminum castings -and in some plastics.
• The Type 25 thread cutting screw, combining a wide thread cutting shank slot and acute cutting edge with spaced threads for low driving/high stripping torque is ideal for cutting mating threads in thermoset plastic materials.
• The Type 17 screw will drill its own hole and cut close mating threads in wood. light plastics and particle board.

Steel Thickness