STI tap for coil threaded inserts

Screw thread insert taps (STI taps) operate in the same manner as “standard” taps, but produce an oversized thread specifically for coil threaded inserts. During insert installation, the threads cut by an STI tap form the coil insert into the desired thread size. STI taps are ideal for tapping holes in 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. We offer STI taps in a wide range of inch, metric, and spark plug sizes to meet your unique requirements.

View our online catalog for full specifications. Request a quote on the STI taps you need, or contact E-Z LOK for more information.


E-Z Coil STI Taps


  • Inch sizes from #2 to 1-1/2
  • Metric sizes from M3 to M39
  • Spark plug sizes from M10 to M18
  • Manufactured from high speed steel (HSS)
  • Straight flute
  • 4-thread lead