Straight & Taper Pipe Taps Standards & Dimensions General Dimensions (Table 311) Dimensions (inch) Nominal Size (inch) Overall Length Thread Length Length of Square Shank DiameterABCD Size ofSquareE 1/16 2-1/8 11/16 3/8 0.3125 0.234 1/8 2-1/8 3/4 3/8 0.3125 0.234 1/8 2-1/8 3/4 3/8 0.4375 0.328 1/4 2-7/16 1-1/16 7/16 0.5625 0.421 3/8 2-9/16 1-1/16 1/2 0.7000 0.531 1/2 3-1/8 1-3/8 5/8 0.6875 0.515 3/4 3-1/4 1-3/8 11/16 0.9063 0.679 1 3-3/4 1-3/4 13/16 1.1250 0.843 1-1/4 4 1-3/4 15/16 1.3125 0.984 1-1/2 4-1/4 1-3/4 1 1.5000 1.125 2 4-1/2 1-3/4 1-1/8 1.8750 1.406 Tolerances Element Range(inch) ToleranceDirection(inch)Cut ThreadGround Thread Overall Length-A 1/16 to 3/4 incl.1 to 4 incl. Plus or MinusPlus or Minus 1/321/16 1/321/16 1/16 to 3/4 incl. Plus or Minus 1/16 1/16 Thread Length-B 1 to 1-1/4 incl. Plus or Minus 3/32 3/32 1-1/2 to 4 incl. Plus or Minus 1/8 1/8 Length of Square-C 1/16 to 3/4 incl.1 to 4 incl. Plus or MinusPlus or Minus 1/321/16 1/321/16 1/16 to 1/8 incl. Minus 0.0070 0.0015 Shank Diameter-D 1/4 to 1/2 incl.3/4 to 1 incl. MinusMinus 0.0070 0.00200.00900.0020 1-1/4 to 4 incl. Minus 0.0090 0.0030 1/16 to 1/8 incl. Minus 0.0040 0.0040 Size of Square-E 1/4 to 3/4 incl. Minus 0.0060 0.0060 1 to 4 incl. Minus 0.0080 0.0080 Thread Limits *Gage Measurement Taper per Foot (inch) (inch) Nominal Size Threads per Tolerance(inch)Inch NPTProjection(+/-)Cut ThreadGroundThreadCut ThreadMin.Max.Ground ThreadMin.Max. 1/16 27 .312 1/16 1/16 23/32 27/32 23/32 25/32 1/8 27 .312 1/16 1/16 23/32 27/32 23/32 25/32 1/4 18 .459 1/16 1/16 23/32 27/32 23/32 25/32 3/8 18 .454 1/16 1/16 23/32 27/32 23/32 25/32 1/2 14 .579 1/16 1/16 23/32 13/16 23/32 25/32 3/4 14 .565 1/16 1/16 23/32 13/16 23/32 25/32 1 11-1/2 .678 3/32 3/32 23/32 13/16 23/32 25/32 1-1/4 11-1/2 .686 3/32 3/32 23/32 13/16 23/32 25/32 1-1/2 11-1/2 .699 3/32 3/32 23/32 13/16 23/32 25/32 2 11-1/2 .667 3/32 3/32 23/32 13/16 23/32 25/32 *Distance small end of tap projects through American Standard Pipe Thread Ring Gage. 666 Threading Technical WWW.OSGTOOL.COM