basicdimensions & gauging practice:ansi/ asme b 1.2-1983 raw material – oil hardened non shrinking steel 3/8” 16 unc 24 unf 32 unef 875 875 1290 50% on 2a thread rings. 2. price for thread rings other than 2a class, diameter above 1" add 12 - 28 UNF : Basic Thread Dimensions (Pitch, minor & major diameters, depth, lead), Tolerance range for all applicable classes and much more #12 - 28 UNF 2A (External) * Permisable values for thread Class 2A # Description Value (Inch) Value (mm) es: Allowance: 0.0009 (Ref) 0.023 (Ref) d: 1- 32 32-UN : Basic Thread Dimensions (Pitch, minor & major diameters, depth, lead), Tolerance range for all applicable classes and much more External Threads. 2A, 3A. Internal Threads. 2B, 3B. 0.028 (Ref) d: Major Diameter: 0.9929 - 0.9989: 25.22 - 25.372: d 2: Pitch Diameter: 0.975 - 0.9786: 24.765 - 24.856: d 3: Minor Diameter (UNR ThreadPitch Chart Nominal Size, Threads per inch and Thread Series A s A r As Area sq. in. Thread Stripping Areas sq. in. per in. of Engagement External Thread Internal Thread Class 2A Class 3A Class 2B Class 3B 0 ‐ 80 UNF 0.00180 0.00151 0.0673 0.0748 0.106 0.116 1 ‐ 64 UNC 0.00263 0.00218 0.0835 0.0913 0.133 0.144 3/8 ‐ 24 UNF 2- 12 12-UN : Basic Thread Dimensions (Pitch, minor & major diameters, depth, lead), Tolerance range for all applicable classes and much more. External Threads. 2A, 3A. Internal Threads. 2B, 3B. 2 - 12 12-UN 2A (External) (UNC/UNF/UNEF) National Pipe (NPT) Dryseal Pipe (BPTF) British Pipe (BSP) ACME; Threading Glossary. Overview The Unified Thread Standard (UTS) defines a 60° thread form in Inch dimensions as described in the ASME B1.1 standard. It is the North American FineThread Table. Basic Dimensions for Fine Thread Series Parts (UNF/UNRF) (measured in inches) Nominal Size. Major Diameter. Threads/inch. Basic Pitch Diameter. Minor Diameter. Threadgeometry - Unified Fine (UNF) All dimensions in mm unless otherwise stated. d1 - Minor thread diameter male. d2 - Minor thread diameter female. d3 - Pitch diameter. d4 - Major diameter. Thread. The28 thread series (28-UN) have been used more or less widely in industry for various applications where the Standard Coarse, Fine or Extra-fine Series were not as applicable. They are now recognized as Standard Unified Thread Series in a specified selection of diameters for each pitch. 5/16" - 1" 1 1/16" - 1 1/2". Nominal Size. Code62 Flange HeadO.D. 1.25 1.62 1.88 2.12 2.50 3.12 British Thread BSPP/BSPT 1/8 - 28 1/4 - 19 3/8 - 19 1/2 - 14 3/4 - 14 1 - 11 1 ¼ - 11 1 ½ - 11 Copper NylonAir Brake Thread 7/16 - 24 17/32 - 24 11/16 - 20 13/16 - 18 1 - 18 SAE 45-FlareThread 5/16 - 24 3/8 - 24 7/16 - 20 1/2 - 20 5/8 - 18 11/16 - 24 3/4 - 16 7/8 - 14 11/16 - 14 Inverted ypwWPyn.