Side-by-Side Comparison
Imperial Threads (UNC/UNF)
#2-56 UNC vs. 3/8"-16 UNC
Comparing 2 standards across 8 specifications. 8 key differences identified.
Comparing:
#2-56 UNC
3/8"-16 UNC
2-56 UNC is a numbered miniature Unified Coarse machine screw thread with a major diameter of 0.0860 inches (2.184 mm) and 56 threads per inch (TPI). Requiring a #50 (0.0700 inch) tap drill, it is widely used in precision model engineering, musical instrument pickups, and micro-electromechanical assemblies.
3/8"-16 UNC is a fractional Unified Coarse machine screw thread with a major diameter of 0.3750 inches (9.525 mm) and 16 threads per inch (TPI). Requiring a 5/16 inch (0.3125 inch) tap drill, it is the international standard for professional photography tripod-to-head mounting studs, cinema camera baseplates, and stage microphone stands.
Specification Comparison Table
8 Parameters| Parameter / Spec | ||
|---|---|---|
|
Nominal Major Diameter
|
0.0860 in (2.184 mm) | 0.3750 in (9.525 mm) |
|
Threads Per Inch (TPI)
|
56 TPI (Coarse pitch: 0.454 mm) | 16 TPI (Coarse pitch: 1.588 mm) |
|
Fine Pitch Equivalent
|
#2-64 UNF (0.397 mm pitch) | 3/8"-24 UNF (1.058 mm pitch) |
|
Recommended Tap Drill Size
|
#50 drill bit (0.0700 in / 1.78 mm) | 5/16 in drill bit (0.3125 in / 7.94 mm) |
|
Minor Diameter (Internal)
|
0.0667 in (1.694 mm) | 0.3073 in (7.805 mm) |
|
Tensile Stress Area
|
0.00370 in² (2.39 mm²) | 0.0775 in² (50.0 mm²) |
|
Thread Profile Angle
|
60 degrees | — |
|
Common Drive Size
|
— | 9/16" Hex (14.28 mm) / 5/16" Allen |