Side-by-Side Comparison
Imperial Threads (UNC/UNF)
#2-56 UNC vs. #8-32 UNC
Comparing 2 standards across 8 specifications. 8 key differences identified.
Comparing:
#2-56 UNC
#8-32 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.
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
8 Parameters| Parameter / Spec | ||
|---|---|---|
|
Nominal Major Diameter
|
0.0860 in (2.184 mm) | 0.1640 in (4.166 mm) |
|
Threads Per Inch (TPI)
|
56 TPI (Coarse pitch: 0.454 mm) | 32 TPI (Coarse pitch: 0.794 mm) |
|
Fine Pitch Equivalent
|
#2-64 UNF (0.397 mm pitch) | #8-36 UNF (0.706 mm pitch) |
|
Recommended Tap Drill Size
|
#50 drill bit (0.0700 in / 1.78 mm) | #29 drill bit (0.1360 in / 3.45 mm) |
|
Minor Diameter (Internal)
|
0.0667 in (1.694 mm) | 0.1302 in (3.307 mm) |
|
Tensile Stress Area
|
0.00370 in² (2.39 mm²) | 0.0140 in² (9.03 mm²) |
|
Thread Profile Angle
|
60 degrees | — |
|
Common Drive Size
|
— | PH2 / Slotted / Square #2 |