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This table presents the
most commonly used small to medium size varieties of SAE hardware. There are two general types of SAE bolts
(sometimes referred to as machine screws). UNF (fine thread pitch) has more threads per inch than the same
diameter bolt in the UNC (coarse thread pitch). Nut dimensions are maximums per SAE. Washer dimensions are for the
regular size (vs. narrow or wide). All dimensions are in inches. Be aware that a search for hardware dimensions
will yield variable results since many reported dimensions are manufacturers' production values, not necessarily
the official SAE/ANSI values. Note: For critical applications, consult
official SAE/ANSI manuals to obtain dimensions. Click here for a table of
metric hardware sizes.
| 0-80 |
UNF |
0.046 |
0.070 |
50 |
0.180 |
0.156 |
0.068 |
0.188 |
| 1-64 |
UNC |
0.056 |
0.081 |
46 |
0.180 |
0.156 |
0.084 |
0.219 |
| 1-72 |
UNF |
0.058 |
0.081 |
46 |
0.180 |
0.156 |
0.084 |
0.219 |
| 2-56 |
UNC |
0.067 |
0.096 |
41 |
0.217 |
0.187 |
0.094 |
0.250 |
| 2-64 |
UNF |
0.069 |
0.096 |
41 |
0.217 |
0.187 |
0.094 |
0.250 |
| 3-48 |
UNC |
0.076 |
0.110 |
35 |
0.217 |
0.187 |
0.109 |
0.312 |
| 3-56 |
UNF |
0.080 |
0.110 |
35 |
0.217 |
0.187 |
0.109 |
0.312 |
| 4-40 |
UNC |
0.085 |
0.129 |
30 |
0.289 |
0.250 |
0.125 |
0.375 |
| 4-48 |
UNF |
0.089 |
0.129 |
30 |
0.289 |
0.250 |
0.125 |
0.375 |
| 5-40 |
UNC |
0.098 |
0.136 |
29 |
0.289 |
0.250 |
0.141 |
0.406 |
| 5-44 |
UNF |
0.100 |
0.136 |
29 |
0.289 |
0.250 |
0.141 |
0.406 |
| 6-32 |
UNC |
0.104 |
0.150 |
25 |
0.361 |
0.312 |
0.156 |
0.438 |
| 6-40 |
UNF |
0.111 |
0.150 |
25 |
0.361 |
0.312 |
0.156 |
0.438 |
| 8-32 |
UNC |
0.130 |
0.177 |
16 |
0.397 |
0.344 |
0.188 |
0.500 |
| 8-36 |
UNF |
0.134 |
0.177 |
16 |
0.397 |
0.344 |
0.188 |
0.500 |
| 10-24 |
UNC |
0.145 |
0.201 |
7 |
0.433 |
0.375 |
0.203 |
0.562 |
| 10-32 |
UNF |
0.156 |
0.201 |
7 |
0.433 |
0.375 |
0.203 |
0.562 |
| 12-24 |
UNC |
0.171 |
0.228 |
1 |
0.433 |
0.438 |
0.234 |
0.625 |
| 12-28 |
UNF |
0.177 |
0.228 |
1 |
0.433 |
0.438 |
0.234 |
0.625 |
| 1/4-20 |
UNC |
0.196 |
0.266 |
H |
0.505 |
0.438 |
0.281 |
0.734 |
| 1/4-28 |
UNF |
0.211 |
0.266 |
H |
0.505 |
0.438 |
0.281 |
0.734 |
| 5/16-18 |
UNC |
0.252 |
0.332 |
Q |
0.577 |
0.500 |
0.344 |
0.875 |
| 5/16-24 |
UNF |
0.267 |
0.332 |
Q |
0.577 |
0.500 |
0.344 |
0.875 |
| 3/8-16 |
UNC |
0.307 |
0.397 |
X |
0.650 |
0.562 |
0.406 |
1.000 |
| 3/8-24 |
UNF |
0.330 |
0.397 |
X |
0.650 |
0.562 |
0.406 |
1.000 |
| 7/16-14 |
UNC |
0.360 |
0.469 |
15/32 |
0.794 |
0.688 |
0.469 |
1.125 |
| 7/16-20 |
UNF |
0.383 |
0.469 |
15/32 |
0.794 |
0.688 |
0.469 |
1.125 |
| 1/2-13 |
UNC |
0.417 |
0.531 |
17/32 |
0.866 |
0.750 |
0.531 |
1.250 |
| 1/2-20 |
UNF |
0.446 |
0.531 |
17/32 |
0.866 |
0.750 |
0.531 |
1.250 |
| 9/16-12 |
UNC |
0.472 |
0.594 |
19/32 |
1.010 |
0.875 |
0.594 |
1.469 |
| 9/16-18 |
UNF |
0.502 |
0.594 |
19/32 |
1.010 |
0.875 |
0.594 |
1.469 |
| 5/8-11 |
UNC |
0.527 |
0.656 |
21/32 |
1.083 |
0.938 |
0.656 |
1.750 |
| 5/8-18 |
UNF |
0.565 |
0.656 |
21/32 |
1.083 |
0.938 |
0.656 |
1.750 |
| 3/4-10 |
UNC |
0.642 |
0.781 |
25/32 |
1.299 |
1.125 |
0.812 |
2.000 |
| 3/4-16 |
UNF |
0.682 |
0.781 |
25/32 |
1.299 |
1.125 |
0.812 |
2.000 |
| 7/8-9 |
UNC |
0.755 |
0.906 |
29/32 |
1.516 |
1.312 |
0.938 |
2.250 |
| 7/8-14 |
UNF |
0.798 |
0.906 |
29/32 |
1.516 |
1.312 |
0.938 |
2.250 |
| 1-8 |
UNC |
0.865 |
1.031 |
1 1/32 |
1.732 |
1.500 |
1.062 |
2.500 |
| 1-12 |
UNF |
0.910 |
1.031 |
1 1/32 |
1.732 |
1.500 |
1.062 |
2.500 |
| 1-14 |
UN |
|
1.031 |
1 1/32 |
1.732 |
1.500 |
1.062 |
2.500 |
| 1 1/8-7 |
UNC |
0.970 |
1.156 |
1 5/32 |
1.949 |
1.688 |
1.188 |
2.750 |
| 1 1/8-8 |
UN |
|
1.156 |
1 5/32 |
1.949 |
1.688 |
1.188 |
2.750 |
| 1 1/8-12 |
UNF |
1.035 |
1.156 |
1 5/32 |
1.949 |
1.688 |
1.188 |
2.750 |
| 1 1/4-7 |
UNC |
1.095 |
1.281 |
1 9/32 |
2.165 |
1.875 |
1.310 |
3.000 |
| 1 1/4-8 |
UN |
|
1.281 |
1 9/32 |
2.165 |
1.875 |
1.310 |
3.000 |
| 1 1/4-12 |
UNF |
1.160 |
1.281 |
1 9/32 |
2.165 |
1.875 |
1.310 |
3.000 |
| 1 3/8-6 |
UNC |
1.195 |
1.406 |
1 13/32 |
2.382 |
2.062 |
1.438 |
3.250 |
| 1 3/8-8 |
UN |
|
1.406 |
1 13/32 |
2.382 |
2.062 |
1.438 |
3.250 |
| 1 3/8-12 |
UNF |
1.285 |
1.406 |
1 13/32 |
2.382 |
2.062 |
1.438 |
3.250 |
| 1 1/2-6 |
UNC |
1.320 |
1.531 |
1 17/32 |
2.598 |
2.250 |
1.562 |
3.500 |
| 1 1/2-8 |
UN |
|
1.531 |
1 17/32 |
2.598 |
2.250 |
1.562 |
3.500 |
| 1 1/2-12 |
UNC |
1.410 |
1.531 |
1 17/32 |
2.598 |
2.250 |
1.562 |
3.500 |
| 1 5/8-8 |
UN |
|
1.656 |
1 21/32 |
2.815 |
2.438 |
1.750 |
3.750 |
| 1 3/4-5 |
UNC |
1.534 |
1.781 |
1 25/32 |
3.031 |
2.625 |
1.875 |
4.000 |
| 1 3/4-8 |
UN |
|
1.781 |
1 25/32 |
3.031 |
2.625 |
1.875 |
4.000 |
| 1 7/8-8 2-4 1/2 2-8 2 1/4-4.5 2 1/4-8 |
UN UNC UN UNC UN |
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| 2 1/2-4 2 1/2-8 2 3/4-4 2 3/4-8 3-4 |
UNC UN UNC UN UNC |
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| 3-8 3 1/4-4 3 1/4-8 3 1/2-4 3 1/2-8 |
UN UNC UN UNC UN |
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| 3 3/4-4 3 3/4-8 4-4 4-8 |
UNC UN UNC UN |
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1) See Drill Sizes page for cross reference.
2) Nut Points is the distance between opposite corners of hex nuts. 3) Nut Flats is the distance between
opposite sides of hex nuts. |
