Side-by-Side Comparison
Imperial Threads (UNC/UNF)
#6-32 UNC vs. #8-32 UNC
Comparing 2 standards across 7 specifications. 6 key differences identified.
Comparing:
#6-32 UNC
#8-32 UNC
6-32 UNC is a numbered Unified Coarse machine screw thread with a major diameter of 0.1380 inches (3.505 mm) and 32 threads per inch (TPI). Requiring a #36 (0.1065 inch) tap drill, it is the universal standard for desktop PC case covers, power supplies, 3.5-inch hard drive mounting, and North American electrical wall outlet boxes.
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
|
0.1380 in (3.505 mm) | 0.1640 in (4.166 mm) |
|
Threads Per Inch (TPI)
|
32 TPI (Coarse pitch: 0.794 mm) | 32 TPI (Coarse pitch: 0.794 mm) |
|
Fine Pitch Equivalent
|
#6-40 UNF (0.635 mm pitch) | #8-36 UNF (0.706 mm pitch) |
|
Recommended Tap Drill Size
|
#36 drill bit (0.1065 in / 2.71 mm) | #29 drill bit (0.1360 in / 3.45 mm) |
|
Minor Diameter (Internal)
|
0.1042 in (2.647 mm) | 0.1302 in (3.307 mm) |
|
Tensile Stress Area
|
0.00909 in² (5.86 mm²) | 0.0140 in² (9.03 mm²) |
|
Common Drive Size
|
PH2 / 1/4" Hex (6.35 mm) | PH2 / Slotted / Square #2 |