Side-by-Side Comparison
Imperial Threads (UNC/UNF)
#10-24 UNC vs. #4-40 UNC
Comparing 2 standards across 9 specifications. 9 key differences identified.
Comparing:
#10-24 UNC
#4-40 UNC
10-24 UNC is a numbered Unified Coarse machine screw thread with a major diameter of 0.1900 inches (4.826 mm) and 24 threads per inch (TPI). Requiring a #25 (0.1495 inch) tap drill, it provides high clamping torque for household appliances, outdoor power equipment, and light mechanical 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
9 Parameters| Parameter / Spec | ||
|---|---|---|
|
Nominal Major Diameter
|
0.1900 in (4.826 mm) | 0.1120 in (2.845 mm) |
|
Threads Per Inch (TPI)
|
24 TPI (Coarse pitch: 1.058 mm) | 40 TPI (Coarse pitch: 0.635 mm) |
|
Fine Pitch Equivalent
|
#10-32 UNF (0.794 mm pitch — widely used in 19" AV racks) | #4-48 UNF (0.529 mm pitch) |
|
Minor Diameter (Internal)
|
0.1449 in (3.680 mm) | 0.0849 in (2.156 mm) |
|
Tensile Stress Area
|
0.0175 in² (11.3 mm²) | 0.00604 in² (3.90 mm²) |
|
Tap Drill Size (UNC)
|
#25 drill bit (0.1495 in / 3.80 mm) | — |
|
Tap Drill Size (#10-32 UNF)
|
#21 drill bit (0.1590 in / 4.04 mm) | — |
|
Recommended Tap Drill Size
|
— | #43 drill bit (0.0890 in / 2.26 mm) |
|
Common Computing Role
|
— | D-sub / VGA / DVI thumbscrew standoffs |