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STI Taps for E-Z Coil™ Threaded Inserts


A screw thread insert tap, or STI tap, operates in the same manner as a "standard" tap. However, the difference is that STI taps produce an oversized thread specifically for E-Z Coil™ inserts.

During installation, the threads cut by an STI tap allow the E-Z Coil™ insert to compress and form into the desired thread size, guaranteeing a snug fit. STI taps are ideal for softer metals that require a strong threaded insert.

E-Z LOK’s E-Z Coil™ STI taps are manufactured from high-speed steel (HSS) for superior durability, and we offer them in a wide range of sizes to meet your unique requirements.

E-Z LOK™ STI tap for E-Z Coil™ threaded inserts

STI Taps for E-Z Coil™

Available In:

  • Inch sizes from #2 to 1-1/2
  • Metric sizes from M3 to M39
  • Spark plug sizes from M10 to M18
  • Straight flute
  • 4-thread lead

A Closer Look at STI Taps from E-Z LOK

Our screw thread insert taps (or STI taps) are ideal for cutting oversized threads that can be used for E-Z coil inserts. They provide a stronger tapped thread for a balanced distribution of loads. When you need a helical coil insert sized down for your project, look no further than our STI taps. To learn more about them, continue reading for resources and information from our experts.

1. What are some examples of softer metals that require a strong threaded insert?

STI taps are ideal for projects involving the following soft metals:

  • Cast iron
  • Mild steel
  • Aluminum

2. What makes E-Z LOK's STI taps so durable?

Our STI taps are durable and dependable thanks to high speed steel. They have the following characteristics:

  • Excellent toughness
  • High wear hardness
  • High retention of hardness and red hardness
  • High working hardness

3. I have a question that wasn't answered here. Where can I ask it?

If you have a question about STI taps or any other of E-Z LOK's products, we're happy to provide our expertise. Fill out our contact form or reach out to our customer service representatives at the following number: 800-234-5613. We also recommend checking out our additional resources below for more information about STI taps.