MAN4MACHINE1-1/2-12 UNF
Unified National Fine
Cut to a finer pitch than UNC at the same nominal diameter, leaving more material at the minor diameter (greater tensile stress area) and more thread engagement per turn -- common on automotive and precision fastening where vibration resistance matters.
- Standard
- ASME B1.1
- Flank angle
- 60° included
- TPI
- 12
- Major diameter
- 1.5000" (basic)
- Other series, same size
Thread profile
A 60 degree included flank angle.
Basic major 1.5000", pitch diameter 1.4459", minor diameter 1.4098" -- theoretical dimensions before any tolerance class is applied.
UNF sizes
| Size | TPI | Major Ø | Pitch Ø | Minor Ø |
|---|---|---|---|---|
| #0 | 80 | 0.0600" | 0.0519" | 0.0465" |
| #1 | 72 | 0.0730" | 0.0640" | 0.0580" |
| #2 | 64 | 0.0860" | 0.0759" | 0.0691" |
| #3 | 56 | 0.0990" | 0.0874" | 0.0797" |
| #4 | 48 | 0.1120" | 0.0985" | 0.0894" |
| #5 | 44 | 0.1250" | 0.1102" | 0.1004" |
| #6 | 40 | 0.1380" | 0.1218" | 0.1109" |
| #8 | 36 | 0.1640" | 0.1460" | 0.1339" |
| #10 | 32 | 0.1900" | 0.1697" | 0.1562" |
| #12 | 28 | 0.2160" | 0.1928" | 0.1773" |
| 1/4 | 28 | 0.2500" | 0.2268" | 0.2113" |
| 5/16 | 24 | 0.3125" | 0.2854" | 0.2674" |
| 3/8 | 24 | 0.3750" | 0.3479" | 0.3299" |
| 7/16 | 20 | 0.4375" | 0.4050" | 0.3834" |
| 1/2 | 20 | 0.5000" | 0.4675" | 0.4459" |
| 9/16 | 18 | 0.5625" | 0.5264" | 0.5024" |
| 5/8 | 18 | 0.6250" | 0.5889" | 0.5649" |
| 3/4 | 16 | 0.7500" | 0.7094" | 0.6823" |
| 7/8 | 14 | 0.8750" | 0.8286" | 0.7977" |
| 1 | 12 | 1.0000" | 0.9459" | 0.9098" |
| 1-1/8 | 12 | 1.1250" | 1.0709" | 1.0348" |
| 1-1/4 | 12 | 1.2500" | 1.1959" | 1.1598" |
| 1-3/8 | 12 | 1.3750" | 1.3209" | 1.2848" |
| 1-1/2 | 12 | 1.5000" | 1.4459" | 1.4098" |
Did you know
Why fine pitch bolts don't just work harder
A UNF bolt isn't a "better" UNC bolt -- it trades thread depth for tensile area. Cutting a shallower thread at the same nominal diameter leaves more metal at the minor diameter, which is why fine threads resist stripping and hold torque under vibration better, even though the coarser UNC thread is actually faster to run down and more tolerant of a dinged or dirty hole.
Tap drill calculator
Try “1/4-20 UNC-2A”, “#10-32 UNF”, or “1-8 UN-3A”. Add “LH” for a left-hand thread.
Basic (theoretical) dimensions and a shop tap drill only -- ASME B1.1's exact Class 1A/2A/3A pitch diameter limits depend on length of thread engagement as well as grade. Consult the standard or a calibrated thread gauge for gauge-critical work.
Calculated live
Basic dimensions
- Major diameter
- 1.5000"
- Pitch diameter
- 1.4459"
- Minor diameter
- 1.4098"
Clearance (normal)
- Clearance drill
- 1-17/32" (1.5313")
Looking for a different size or series? Open the full calculator →