Side-by-Side Comparison
Imperial Threads (UNC/UNF)
1/4"-20 UNC vs. #10-24 UNC
Comparing 2 standards across 9 specifications. 9 key differences identified.
Comparing:
1/4"-20 UNC
#10-24 UNC
1/4"-20 UNC is a fractional Unified Coarse machine screw thread with a major diameter of 0.2500 inches (6.350 mm) and 20 threads per inch (TPI). Requiring a #7 (0.2010 inch) tap drill, it is the universal global standard under ISO 1222 for camera tripod mounting sockets, studio light stands, and general machinery bolting.
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.
Specification Comparison Table
9 Parameters| Parameter / Spec | ||
|---|---|---|
|
Nominal Major Diameter
|
0.2500 in (6.350 mm) | 0.1900 in (4.826 mm) |
|
Threads Per Inch (TPI)
|
20 TPI (Coarse pitch: 1.270 mm) | 24 TPI (Coarse pitch: 1.058 mm) |
|
Fine Pitch Equivalent
|
1/4"-28 UNF (0.907 mm pitch) | #10-32 UNF (0.794 mm pitch — widely used in 19" AV racks) |
|
Minor Diameter (Internal)
|
0.1959 in (4.976 mm) | 0.1449 in (3.680 mm) |
|
Tensile Stress Area
|
0.0318 in² (20.5 mm²) | 0.0175 in² (11.3 mm²) |
|
Recommended Tap Drill Size
|
#7 drill bit (0.2010 in / 5.10 mm) or 13/64 in | — |
|
Common Drive Size
|
7/16" Hex (11.11 mm) / 3/16" Allen (4.76 mm) | — |
|
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) |