Threaded fasteners such as screws and bolts fasten objects, large and small, together and hold them in place. While some might interchange screws and bolts, there are some differences.
An externally threaded fastener that has thread form which prohibits assembly with a nut having a straight thread of multiple pitch length is a screw. (Example: wood screws, tapping screws.)
A screw is a fastener capable of being inserted into holes in assembled parts, of mating with a preformed internal thread or forming its own thread, and of being tightened or released by torquing the head.
An externally threaded fastener which is prevented from being turned during assembly and which can be tightened or released only by torquing a nut is a bolt. (Example: round head bolts, track bolts, plow bolts.)
A bolt is a fastener designed for insertion through holes in assembled parts and is normally intended to be tightened or released by torquing a nut.
Our screws and bolts can be customized to your application and industry. Please review and download our screws and bolts size chart below.
| Nominal Size &Threads/lnch & Series Designation | Allowance | Major Diameter | Pitch Diameter | ||||
| Max | Min | Max | Min | Tolerance | |||
| 0-80 1-64 1-72 2-56 2-64 |
UNF UNC UNF UNG UNF |
0.0005 0.0006 0.0006 0.0006 0.0006 |
0.0595 0.0724 0.0724 0.0854 0.0854 |
0.0563 0.0686 0.0689 0.0813 0.0816 |
0.0514 0.0623 0.0634 0.0738 0.0753 |
0.0496 0.0603 0.0615 0.0717 0.0733 |
0.0018 0.0020 0.0019 0.0021 0.0020 |
| 3-48 3-56 4-40 4-48 5-40 |
UNG UNF UNG UNF UNC |
0.0007 0.0007 0.0008 0.0007 0.0008 |
0.0938 0.0983 0.1112 0.1113 0.1242 |
0.0938 0.0942 0.1061 0.1068 0.1191 |
0.0848 0.0867 0.0950 0.0978 0.1080 |
0.0825 0.0845 0.0925 0.0954 0.1054 |
0.0023 0.0022 0.0025 0.0024 0.0026 |
| 5-44 6-32 6-40 8-32 8-36 |
UNF UNG UNF UNG UNF |
0.0007 0.0008 0.0008 0.0009 0.0008 |
0.1243 0.1372 0.1372 0.1631 0.1632 |
0.1195 0.1312 0.1321 0.1571 0.1577 |
0.1095 0.1169 0.1210 0.1428 0.1452 |
0.1070 0.1141 0.1184 0.1399 0.1424 |
0.0025 0.0028 0.0026 0.0029 0.0028 |
| 10-24 10-32 12-24 12-28 1/4-20 |
UNG UNF UNG UNF UNG |
0.0010 0.0009 0.0010 0.0010 0.0011 |
0.1890 0.1891 0.2150 0.2150 0.2489 |
0.1818 0.1831 0.2078 0.2085 0.2408 |
0.1619 0.1688 0.1879 0.1918 0.2164 |
0.1586 0.1658 0.1845 0.1886 0.2127 |
0.0033 0.0030 0.0034 0.0032 0.0037 |
| 1/4-28 5/16-18 5/16-24 3/8-16 3/8-24 |
UNF UNG UNF UNG UNF |
0.0010 0.0012 0.0011 0.0013 0.0011 |
0.2490 0.3113 0.3114 0.3737 0.3739 |
0.2425 0.3026 0.3042 0.3643 0.3667 |
0.2258 0.2752 0.2843 0.3331 0.3468 |
0.2225 0.2712 0.2806 0.3287 0.3430 |
0.0033 0.0040 0.0037 0.0044 0.0038 |
| 7/16-14 7/16-20 1/2-13 1/2-20 9/16-12 |
UNG UNF UNG UNF UNG |
0.0014 0.0013 0.0015 0.0013 0.0016 |
0.4361 0.4362 0.4985 0.4987 0.5609 |
0.4258 0.4281 0.4876 0.4906 0.5495 |
0.3897 0.4037 0.4485 0.4662 0.5068 |
0.3850 0.3995 0.4435 0.4619 0.5016 |
0.0047 0.0042 0.0050 0.0043 0.0052 |
| 9/16-18 5/8-11 5/8-18 3/4-10 3/4-16 |
UNF UNG UNF UNG UNF |
0.0014 0.0016 0.0014 0.0018 0.0015 |
0.5611 0.6234 0.6236 0.7482 0.7485 |
0.5524 0.6113 0.6149 0.7353 0.7391 |
0.5250 0.5644 0.5875 0.6832 0.7079 |
0.5205 0.5589 0.5828 0.6773 0.7029 |
0.0045 0.0055 0.0047 0.0059 0.0050 |
| 7/8-9 7/8-14 1-8 1-12 1-14 |
UNG UNF UNG UNF UNS |
0.0019 0.0016 0.0020 0.0018 0.0017 |
0.8731 0.0834 0.9980 0.9982 0.9983 |
0.8592 0.8631 0.9830 0.9868 0.9880 |
0.8009 0.8270 0.9168 0.9441 0.9519 |
0.7946 0.8216 0.9100 0.9382 0.9463 |
0.0063 0.0054 0.0068 0.0059 0.0056 |
| 11/8-7 11/8-8 11/8-12 11/4-7 1114-8 |
UNG UN UNF UNG UN |
0.0022 0.0021 0.0018 0.022 0.0021 |
1.1228 1.1229 1.1232 1.2478 1.2479 |
1.1064 1.1079 1.1118 1.2314 1.2329 |
1.0300 1.0417 1.0691 1.1550 1.1667 |
1.0228 1.0348 1.0631 1.1476 1.1597 |
0.0072 0.0069 0.0060 0.0074 0.0070 |
| 11/4-12 1 3/8-6 1 3/8-8 1 3/8-12 11/2-6 |
UNF UNC UN UNF UNC |
0.0018 0.0024 0.0022 0.0019 0.0024 |
1.2482 1.3726 1.3728 1.3731 1.4976 |
1.2368 1.3544 1.3578 1.3617 1.4794 |
1.1941 1.2643 1.2916 1.3190 1.3893 |
1.1879 1.2563 1.2844 1.3127 1.3812 |
0.0062 0.0080 0.0072 0.0063 0.0081 |
| 1 1/2-8 1 1/2-12 1 5/8-8 1 3/4-5 1 3/4-8 |
UN UNC UN UNC UN |
0.0022 0.0019 0.0022 0.0027 0.0023 |
1.4978 1.4981 1.6228 1.7473 1.7477 |
1.4828 1.4867 1.6087 1.7268 1.7327 |
1.4166 1.4440 1.5416 1.6174 1.6665 |
1.4093 1.4376 1.5342 1.6085 1.6590 |
0.0073 0.0064 0.0074 0.0089 0.0075 |
| 1 7/8-8 2-4 1/2 2-8 2 1/4-4.5 2 1/4-8 |
UN UNC UN UNC UN |
0.0023 0.0029 0.0023 0.0029 0.0024 |
1.8727 1.9971 1.9977 2.2471 2.2476 |
1.8577 1.9751 1.9827 2.2251 2.2326 |
1.7915 1.8528 1.9165 2.1028 2.1664 |
1.7838 1.8433 1.9087 2.0931 2.1584 |
0.0077 0.0095 0.0078 0.0097 0.0080 |
| 2 1/2-4 2 1/2-8 2 3/4-4 2 3/4-8 3-4 |
UNC UN UNC UN UNC |
0.0031 0.0024 0.0032 0.0025 0.0032 |
2.4969 2.4976 2.7468 2.7475 2.9968 |
2.4731 2.4826 2.7230 2.7325 2.9730 |
2.3345 2.4164 2.5844 2.6663 2.8344 |
2.3241 2.4082 2.5739 2.6580 2.8237 |
0.0104 0.0082 0.0105 0.0083 0.0107 |
| 3-8 3 1/4-4 3 1/4-8 3 1/2-4 3 1/2-8 |
UN UNC UN UNC UN |
0.0026 0.0033 0.0026 0.0033 0.0026 |
2.9974 3.2467 3.2474 3.4967 3.4974 |
2.9824 3.2229 3.2324 3.4729 3.4824 |
2.9162 3.0843 3.1662 3.3343 3.4162 |
2.9077 3.0734 3.1575 3.3233 3.4074 |
0.0085 0.0109 0.0087 0.0110 0.0088 |
| 3 3/4-4 3 3/4-8 4-4 4-8 |
UNC UN UNC UN |
0.0034 0.0027 0.0034 0.0027 |
3.7466 3.7473 3.9966 3.9973 |
3.7228 3.7323 3.9728 3.9823 |
3.5842 3.6661 3.8342 3.9161 |
3.5730 3.6571 3.8229 3.9070 |
0.0112 0.0090 0.0113 0.0091 |