
Taper Pipe Taps Measurement of Taper Pipe Taps, Reaming Data and Tap Drill Sizes (Table 357) Size ProjectionNPT & NTFSAE-SHORT Ream Dia.Large EndGageWidthL1Reamed Tap Drill Tap DrillLengthfor Use w/for Use w/oL1 + L3ReamingReaming Min. Max. Min. Max. 1/16-27 0.250 0.375 0.222 0.259 0.2515 0.1600 0.2711 15/64 C 1/8-27 0.250 0.375 0.222 0.259 0.3340 0.1615 0.2726 21/64 Q 1/4-18 0.397 0.521 0.333 0.389 0.4472 0.2278 0.3945 27/64 7/16 3/8-18 0.392 0.516 0.333 0.389 0.5826 0.240 0.4067 9/16 9/16 1/2-14 0.517 0.641 0.429 0.500 0.7213 0.320 0.5343 11/16 45/64 3/4-14 0.503 0.627 0.429 0.500 0.9317 0.339 0.5533 57/64 29/32 1-11½ 0.584 0.772 – – 1.1691 0.400 0.6609 1-1/8 1-9/64 1¼-11½ 0.592 0.780 – – 1.1538 0.420 0.6809 1-15/32 1-31/64 1½-11½ 0.606 0.792 – – 1.7528 0.420 0.6809 1-45/64 1-23/32 2-11½ 0.574 0.760 – – 2.2267 0.436 0.6969 2-3/16 2-3/16 Projection Thru Ring Gage Reamed Hole Data 668 Threading Technical WWW.OSGTOOL.COM