ExternalThread Dimensions EXTERNAL THREADS-CLASS 2A ASME B1.1 Nominal Size Series Designation Allowance 3/8-24 UNF 0.0011 0.3739 0.3667 0.3468 0.3430 0.0038 7/16-14 UNC 0.0014 0.4361 0.4258 0.3897 0.3850 0.0047 Cap Screw threads Home Thread Gages. Unified Inch Thread Gages. 3/8-24 UNF 2A Go Set Plug. SKU. 3/8-24-TSP-2A GO. $107.00. Accessories. Taperlock Handle-2 + $13.00. Calibration. Long threadsymbol: G nominal diameter d₁ [mm]: 16.662 mm nominal size: 3/8 pitch [mm]: 1.337 mm pitch [in]: 0.053 "threads per inch: 19 type of gage: go thread sense of rotation: right hand standard of dimensions: DIN2285 gauge system: Gauge dimensions according to DIN EN ISO 228-2. 3/8-24 UNF-2A; 3/8-24 UNF-3A; 3/8-24 UNJF-3A; 3/8-32 UNEF TapDrill Sizes for #1 - 72 UNF. If not specified, assume a thread depth of 75%. You can learn more about thread depth in tapping here. To get the tap drill size in other depths, use our Tap Drill Size Calculator . Thread Depth. Tap 15/8 - 18 UNEF : Basic Thread Dimensions (Pitch, minor & major diameters, depth, lead), Tolerance range for all applicable classes and much more 1 5/8 - 18 UNEF 2A (External) * Permisable values for thread Class 2A # Description Value (Inch) Value (mm) es: (UNC/UNF/UNEF) National Pipe (NPT) Dryseal Pipe (BPTF) British Pipe (BSP) ACME 8– Thread Series (8UN) This series is used for diameters one inch and above. Coarse Thread Series - UNC Fine Thread Series - UNF 8-Thread Series - 8UN; Nominal Size and Threads Per In. Basic Pitch Dia. Section at Minor Dia. 3 ⁄ 8 - 16: 0.3344: 0.0678: 0.0775: 3 ⁄ 8 - 24: 0.3479: UNC= Unified National Coarse Screw Thread. This is one of three graded series: UNC (Unified National Corase); UNF (Unified National Fine); and UNEF (Unified National Extra Fine). The Nominal Major Diameter and Threads-per-inch (Pitch) are defined by ANSI/ASME B1.1 and are the choices for the customary Unified screws and nuts. 58 - 18 UNF : Basic Thread Dimensions (Pitch, minor & major diameters, depth, lead), Tolerance range for all applicable classes and much more. 5/8 - 18 UNF 2A (External) * Permisable values for thread Class 2A # Description Value (Inch) Value (mm) es: Allowance: 0.0013 (Ref) 0.033 (Ref) d: qVnIz.