Side-by-Side Comparison
Imperial Threads (UNC/UNF)
3/8"-16 UNC vs. #8-32 UNC
Comparing 2 standards across 7 specifications. 7 key differences identified.
Comparing:
3/8"-16 UNC
#8-32 UNC
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.
8-32 UNC is a numbered Unified Coarse machine screw thread with a major diameter of 0.1640 inches (4.166 mm) and 32 threads per inch (TPI). Requiring a #29 (0.1360 inch) tap drill, it is the standard fastener for North American electrical ceiling junction boxes, light fixtures, and kitchen cabinet hardware knobs.
Specification Comparison Table
7 Parameters| Parameter / Spec | ||
|---|---|---|
|
Nominal Major Diameter
|
0.3750 in (9.525 mm) | 0.1640 in (4.166 mm) |
|
Threads Per Inch (TPI)
|
16 TPI (Coarse pitch: 1.588 mm) | 32 TPI (Coarse pitch: 0.794 mm) |
|
Fine Pitch Equivalent
|
3/8"-24 UNF (1.058 mm pitch) | #8-36 UNF (0.706 mm pitch) |
|
Recommended Tap Drill Size
|
5/16 in drill bit (0.3125 in / 7.94 mm) | #29 drill bit (0.1360 in / 3.45 mm) |
|
Minor Diameter (Internal)
|
0.3073 in (7.805 mm) | 0.1302 in (3.307 mm) |
|
Tensile Stress Area
|
0.0775 in² (50.0 mm²) | 0.0140 in² (9.03 mm²) |
|
Common Drive Size
|
9/16" Hex (14.28 mm) / 5/16" Allen | PH2 / Slotted / Square #2 |