UNC / UNF Thread Reference
Printable shop wall chart: UNC / UNF Thread Reference. Free letter-size PDF to print and post at the counter; 25 x 36 inch poster version available.
| Size | UNC TPI | UNC tap drill | UNF TPI | UNF tap drill |
|---|---|---|---|---|
| #4 | 40 | #43 (0.0890) | 48 | #42 (0.0935) |
| #6 | 32 | #36 (0.1065) | 40 | #33 (0.1130) |
| #8 | 32 | #29 (0.1360) | 36 | #29 (0.1360) |
| #10 | 24 | #25 (0.1495) | 32 | #21 (0.1590) |
| 1/4 | 20 | #7 (0.2010) | 28 | #3 (0.2130) |
| 5/16 | 18 | F (0.2570) | 24 | I (0.2720) |
| 3/8 | 16 | 5/16 (0.3125) | 24 | Q (0.3320) |
| 7/16 | 14 | U (0.3680) | 20 | 25/64 (0.3906) |
| 1/2 | 13 | 27/64 (0.4219) | 20 | 29/64 (0.4531) |
| 9/16 | 12 | 31/64 (0.4844) | 18 | 33/64 (0.5156) |
| 5/8 | 11 | 17/32 (0.5312) | 18 | 37/64 (0.5781) |
| 3/4 | 10 | 21/32 (0.6562) | 16 | 11/16 (0.6875) |
| 7/8 | 9 | 49/64 (0.7656) | 14 | 13/16 (0.8125) |
| 1 | 8 | 7/8 (0.8750) | 12 | 59/64 (0.9219) |
| 1-1/8 | 7 | 63/64 (0.9844) | 12 | 1-3/64 (1.0469) |
| 1-1/4 | 7 | 1-7/64 (1.1094) | 12 | 1-11/64 (1.1719) |
| 1-3/8 | 6 | 1-7/32 (1.2188) | 12 | 1-19/64 (1.2969) |
| 1-1/2 | 6 | 1-11/32 (1.3438) | 12 | 1-27/64 (1.4219) |
Tap drills are the common shop set for about 75% thread, not the ASME B1.1 basic minor diameter. UNC and UNF nuts are not interchangeable. UNR, 8-UN and UNEF series are not covered on this shop chart.
These tables carry the same figures as the printed sheet below.
The printed sheet
25 x 36 inch poster version
For the full-size shop poster, tell us where to send it.
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Text version of this sheet
UNC - COARSE
UNF - FINE
ASME B1.1 Unified inch threads · threads per inch and tap drills
Size
UNC TPI
UNC tap drill
UNF TPI
UNF tap drill
#4
40
#43 (0.0890)
48
#42 (0.0935)
#6
32
#36 (0.1065)
40
#33 (0.1130)
#8
32
#29 (0.1360)
36
#29 (0.1360)
#10
24
#25 (0.1495)
32
#21 (0.1590)
1/4
20
#7 (0.2010)
28
#3 (0.2130)
5/16
18
F (0.2570)
24
I (0.2720)
3/8
16
5/16 (0.3125)
24
Q (0.3320)
7/16
14
U (0.3680)
20
25/64 (0.3906)
1/2
13
27/64 (0.4219)
20
29/64 (0.4531)
9/16
12
31/64 (0.4844)
18
33/64 (0.5156)
5/8
11
17/32 (0.5312)
18
37/64 (0.5781)
3/4
10
21/32 (0.6562)
16
11/16 (0.6875)
7/8
9
49/64 (0.7656)
14
13/16 (0.8125)
1
8
7/8 (0.8750)
12
59/64 (0.9219)
1-1/8
7
63/64 (0.9844)
12
1-3/64 (1.0469)
1-1/4
7
1-7/64 (1.1094)
12
1-11/64 (1.1719)
1-3/8
6
1-7/32 (1.2188)
12
1-19/64 (1.2969)
1-1/2
6
1-11/32 (1.3438)
12
1-27/64 (1.4219)
Tap drills are the common shop set for about 75% thread, not the ASME B1.1 basic minor diameter. UNC and UNF nuts are not interchangeable. UNR, 8-UN and UNEF series are not
covered on this shop chart.
The Fastener App | TheFastenerApp.com
Fastener Guide reference FG-DDA560 · thefastenerapp.com/fastener-guide/wall-charts/unc-unf-thread-reference · © The Fastener App. Reference only — verify the current governing standard, drawing and manufacturer data before specifying or installing.
