Overall Thread Thread+Neck Shank Size of Length of length length length dia. square square L ℓ ℓn Ds K ℓk ZELX NI SP STI Spiral Fluted Taps for Nickel Base Alloys, for Helical Coil Wire Screw Thread Inserts Size Class Code Chamfer L ℓ ℓn Ds K ℓk No. of Type (for blind hole) Spiral Fluted Taps (inch) (inch) (inch) (inch) (inch) (inch) flutes GH2 Y87448 3P STI 1/4-20UNC Y87458 2.718 0.472 1.125 0.318 0.238 0.375 3 3 GH3 Y87058 1.5P GH2 Y87449 (for through hole) Spiral Fluted Taps STI 1/4-28UNF 3P 2.718 0.394 1.125 0.318 0.238 0.375 3 3 GH3 Y87459 GH3 Y87460 STI 5/16-18UNC 3P 2.937 0.551 1.25 0.381 0.286 0.437 3 3 GH4 Y87470 GH2 Y87451 (for through hole) Spiral Pointed Taps 3P STI 5/16-24UNF Y87461 2.937 0.394 1.25 0.381 0.286 0.437 3 3 GH3 Y87061 1.5P GH3 Y87462 STI 3/8-16UNC 3P 3.375 0.630 - 0.367 0.275 0.437 3 4 GH4 Y87472 Y87453 3P Hand Taps GH2 STI 3/8-24UNF Y87063 1.5P 3.156 0.472 - 0.323 0.242 0.406 3 4 GH3 Y87463 3P STI 7/16-14UNC GH3 Y87464 3P 3.593 0.709 - 0.429 0.322 0.5 3 4 GH3 Y87465 Carbide Taps Cemented STI 7/16-20UNF 3P 3.375 0.472 - 0.367 0.275 0.437 3 4 GH4 Y87475 STI 1/2-13UNC GH3 Y87466 3P 3.812 0.748 - 0.480 0.36 0.562 3 4 Y87467 3P STI 1/2-20UNF GH3 3.593 0.512 - 0.429 0.322 0.5 3 4 Y87067 1.5P Roll Taps Simple Inspection Tools Pipe Taps Thread Mills Dies Center Drills Centering Tools ANSI SP-32 219