Side-by-Side Comparison
Imperial Threads (UNC/UNF)
#2-56 UNC vs. #4-40 UNC
Comparing 2 standards across 8 specifications. 8 key differences identified.
Comparing:
#2-56 UNC
#4-40 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.
4-40 UNC is a numbered Unified Coarse machine screw thread with a major diameter of 0.1120 inches (2.845 mm) and 40 threads per inch (TPI). Requiring a #43 (0.0890 inch) tap drill, it is the worldwide computing standard for D-subminiature connector jackscrews (VGA, DVI, RS-232 serial ports).
Specification Comparison Table
8 Parameters| Parameter / Spec | ||
|---|---|---|
|
Nominal Major Diameter
|
0.0860 in (2.184 mm) | 0.1120 in (2.845 mm) |
|
Threads Per Inch (TPI)
|
56 TPI (Coarse pitch: 0.454 mm) | 40 TPI (Coarse pitch: 0.635 mm) |
|
Fine Pitch Equivalent
|
#2-64 UNF (0.397 mm pitch) | #4-48 UNF (0.529 mm pitch) |
|
Recommended Tap Drill Size
|
#50 drill bit (0.0700 in / 1.78 mm) | #43 drill bit (0.0890 in / 2.26 mm) |
|
Minor Diameter (Internal)
|
0.0667 in (1.694 mm) | 0.0849 in (2.156 mm) |
|
Tensile Stress Area
|
0.00370 in² (2.39 mm²) | 0.00604 in² (3.90 mm²) |
|
Thread Profile Angle
|
60 degrees | — |
|
Common Computing Role
|
— | D-sub / VGA / DVI thumbscrew standoffs |