U.S. Bolt Head / Wrench Size Chart
| Bolt Diameter | Wrench Size | |
|---|---|---|
| Hex / Lag / Square Bolts | Heavy Hex Bolts | |
| #6 | 1/4" | -- |
| #8 | 1/4" | -- |
| #10 | 5/16" | -- |
| #12 | 5/16" | -- |
| 1/4" | 7/16" | -- |
| 5/16" | 1/2" | -- |
| 3/8" | 9/16" | -- |
| 7/16" | 5/8" | -- |
| 1/2" | 3/4" | 7/8" |
| 9/16" | 13/16" | -- |
| 5/8" | 15/16" | 1 1/16" |
| 3/4" | 1 1/8" | 1 1/4" |
| 7/8" | 1 5/16" | 1 7/16" |
| 1" | 1 1/2" | 1 5/8" |
| 1 1/8" | 1 11/16" | 1 3/4" |
| 1 1/4" | 1 7/8" | 2" |
Nut Compatibility Chart
| Grade of Bolt | Surface Finish | Nominal Size | A563 Grade & ANSI Nut Style | |||
|---|---|---|---|---|---|---|
| Recommended | Suitable | |||||
| Hex | Heavy Hex | Hex | Heavy Hex | |||
| A307 Grade A & C | Any | 1/4" to 11/2" | A | -- | B, D, DH | A, B, C, D, DH,DH3 |
| 1 1/2" to 2" | -- | A | A | C, D, DH,DH3 | ||
| 2" to 4" | -- | A | -- | C, D, DH,DH3 | ||
| A307 Grade B | Any | 1/4" to 11/2" | -- | A | B, D, DH | B, C, D, DH,DH3 |
| 1 1/2" to 2" | -- | A | A | -- | ||
| 2" to 4" | -- | A | -- | -- | ||
| A325 Type 1 | Plain | 1/2" to 1 1/2" | -- | C | -- | C3, D, DH, DH3 |
| Galvanized | 1 1/2" to 2" | -- | A | A | -- | |
| A325 Type 3 | Plain | 1/2" to 1 1/2" | -- | C3 | -- | DH3 |
| A354 Grade BC | Plain | 1/4" to 1 1/2" | -- | C | D, DH | C3, D, DH, DH3 |
| >11/2" to 4" | -- | C | -- | C3, D, DH, DH3 | ||
| Galvanized | 1/4" to 1 1/2" | -- | DH | -- | -- | |
| >11/2" to 4" | -- | DH | -- | -- | ||
| A354 Grade BD | Plain | 1/4" to 11/2" | -- | DH | DH | D, DH, DH3 |
| >11/2" to 4" | -- | DH | -- | DH3 | ||
| A449 | Plain | 1/4" to 11/2" | B | -- | D, DH | B, C, C3, D, DH, DH3 |
| >11/2" to 3" | -- | A | -- | C, C3, D, DH, DH3 | ||
| Galvanized | 1/4" to 11/2" | -- | DH | D, DH | D | |
| >11/2" to 3" | -- | DH | -- | D | ||
| A490 Type 1 | Plain | 1/2" to 11/2" | -- | DH | -- | DH3 |
| A490 Type 3 | Plain | 1/2" to 11/2" | -- | DH | -- | DH3 |
| A687 | Plain | 5/8" to 3" | -- | D | -- | DH, DH3 |
| Galvanized | 5/8" to 3" | -- | DH | -- | -- | |
| F1554 Grade 36 | Any | 1/4" to 11/2" | A | -- | B, D, DH | A, B, C, D, DH, DH3 |
| >11/2" to 4" | -- | A | -- | C, D, DH, DH3 | ||
| F1554 Grade 55 | Plain | 1/4" to 11/2" | A | -- | B, D, DH | A, B, C, D, DH, DH3 |
| >11/2" to 4" | -- | A | -- | C, D, DH, DH3 | ||
| Galvanized | 1/4" to 4" | -- | A | -- | C, D, DH, DH3 | |
| F1554 Grade 105 | Plain | 1/4" to 11/2" | D | -- | -- | DH, DH3 |
| >11/2" to 3" | -- | DH | -- | DH3 | ||
| Galvanized | 1/4" to 4" | -- | DH | -- | DH3 | |
Thread Pitch Chart
| Coarse Thread (UNC) | Fine Thread (UNF) | 8-Thread (8UN) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
Diameter - Threads |
Basic Pitch Diameter (In.) |
Section at Minor Diameter (Sq In.) |
Tensile Stress Area (Sq In.) |
Diameter - Threads |
Basic Pitch Diameter (In.) |
Section at Minor Diameter (Sq In.) |
Tensile Stress Area (Sq In.) |
Diameter - Threads |
Basic Pitch Diameter (In.) |
Section at Minor Diameter (Sq In.) |
Tensile Stress Area (Sq In.) |
| -- | -- | -- | -- | #0-80 | 0.0519 | 0.00151 | 0.00180 | -- | -- | -- | -- |
| #1-64 | 0.0629 | 0.00218 | 0.00263 | #1-72 | 0.0640 | 0.00237 | 0.00278 | -- | -- | -- | -- |
| #2-56 | 0.0744 | 0.00310 | 0.00370 | #2-64 | 0.0759 | 0.00339 | 0.00394 | -- | -- | -- | -- |
| #3-48 | 0.0855 | 0.00406 | 0.00487 | #3-56 | 0.0874 | 0.00451 | 0.00523 | -- | -- | -- | -- |
| #4-40 | 0.0958 | 0.00496 | 0.00604 | #4-48 | 0.0985 | 0.00566 | 0.00661 | -- | -- | -- | -- |
| #5-40 | 0.1088 | 0.00672 | 0.00796 | #5-44 | 0.1102 | 0.00716 | 0.00830 | -- | -- | -- | -- |
| #6-32 | 0.1177 | 0.00745 | 0.00909 | #6-40 | 0.1218 | 0.00874 | 0.01015 | -- | -- | -- | -- |
| #8-32 | 0.1437 | 0.01196 | 0.0140 | #8-36 | 0.1460 | 0.01285 | 0.01474 | -- | -- | -- | -- |
| #10-24 | 0.1629 | 0.01450 | 0.0175 | #10-32 | 0.1697 | 0.0175 | 0.0200 | -- | -- | -- | -- |
| #12-24 | 0.1889 | 0.0206 | 0.0242 | #12-24 | 0.1928 | 0.0226 | 0.0258 | -- | -- | -- | -- |
| 1/4"-20 | 0.2175 | 0.0269 | 0.0318 | 1/4"-28 | 0.2268 | 0.0326 | 0.0364 | -- | -- | -- | -- |
| 5/16"-18 | 0.2764 | 0.0454 | 0.0524 | 5/16"-24 | 0.2854 | 0.0524 | 0.0580 | -- | -- | -- | -- |
| 3/8"-16 | 0.3344 | 0.0678 | 0.0775 | 3/8"-24 | 0.3479 | 0.0809 | 0.0878 | -- | -- | -- | -- |
| 7/16"-14 | 0.3911 | 0.0933 | 0.1063 | 7/16"-20 | 0.4050 | 0.1090 | 0.1187 | -- | -- | -- | -- |
| 1/2"-13 | 0.4500 | 0.1257 | 0.1419 | 1/2"-20 | 0.4675 | 0.1486 | 0.1599 | -- | -- | -- | -- |
| 9/16"-12 | 0.5084 | 0.162 | 0.182 | 9/16"-18 | 0.5264 | 0.189 | 0.203 | -- | -- | -- | -- |
| 5/8"-11 | 0.5660 | 0.202 | 0.226 | 5/8"-18 | 0.5889 | 0.240 | 0.256 | -- | -- | -- | -- |
| 3/4"-10 | 0.6850 | 0.302 | 0.334 | 3/4"-16 | 0.7094 | 0.351 | 0.373 | -- | -- | -- | -- |
| 7/8"-9 | 0.8028 | 0.419 | 0.462 | 7/8"-14 | 0.8286 | 0.180 | 0.509 | -- | -- | -- | -- |
| 1"-8 | 0.9188 | 0.551 | 0.606 | 1"-12 | 0.9459 | 0.625 | 0.663 | 1"-8 | 0.9188 | 0.551 | 0.606 |
| 11/8"-7 | 1.0322 | 0.693 | 0.763 | 11/8"-12 | 1.0709 | 0.812 | 0.856 | 11/8"-8 | 1.0438 | 0.728 | 0.790 |
| 11/4"-7 | 1.1572 | 0.890 | 0.969 | 11/4"-12 | 1.1959 | 1.024 | 1.073 | 11/4"-8 | 1.1688 | 0.929 | 1.000 |
| 13/8"-6 | 1.2667 | 1.054 | 1.405 | 13/8"-12 | 1.3209 | 1.260 | 1.315 | 13/8"-8 | 1.1688 | 0.929 | 1.233 |
| 11/2"-6 | 1.3917 | 1.294 | 1.405 | 11/2"-12 | 1.4459 | 1.521 | 1.581 | 11/2"-8 | 1.4188 | 1.405 | 1.492 |
| --" | -- | -- | -- | -- | -- | -- | -- | 15/8"-8 | 1.5438 | 1.68 | 1.78 |
| 13/4"-5 | 1.621 | 1.74 | 1.90 | -- | -- | -- | -- | 13/4"-8 | 1.6688 | 1.98 | 2.08 |
| --" | -- | -- | -- | -- | -- | -- | -- | 17/8"-8 | 1.7938 | 2.30 | 2.41 |
| 2"-4.5 | 1.8557 | 2.30 | 2.50 | -- | -- | -- | -- | 2"-8 | 1.9188 | 2.65 | 2.77 |
| 21/4"4.5 | 2.1057 | 3.02 | 3.25 | -- | -- | -- | -- | 21/4"-8 | 2.1688 | 3.42 | 3.56 |
| 21/2"-4 | 2.3376 | 3.72 | 4.00 | -- | -- | -- | -- | 21/2"-8 | 2.4188 | 4.29 | 4.44 |
| 23/4"-4 | 2.5876 | 4.62 | 4.93 | -- | -- | -- | -- | 23/4"-8 | 2.6688 | 5.26 | 5.43 |
| 3"-4 | 2.8376 | 5.62 | 5.97 | -- | -- | -- | -- | 3"-8 | 2.9188 | 6.32 | 6.51 |
| 31/4"-4 | 3.0876 | 6.72 | 7.10 | -- | -- | -- | -- | 31/4"-8 | 3.1688 | 7.49 | 7.69 |
| 31/2"-4 | 3.3376 | 7.92 | 8.33 | -- | -- | -- | -- | 31/2"-8 | 3.4188 | 8.75 | 8.96 |
| 33/4"-4 | 3.5876 | 9.21 | 9.66 | -- | -- | -- | -- | 33/4"-8 | 3.6688 | 10.11 | 10.34 |
| 4"-4 | 3.8376 | 10.61 | 11.08 | -- | -- | -- | -- | 4"-8 | 3.9188 | 11.57 | 11.81 |
Unit Conversion Chart
| Metric | Imperial | Metric | Imperial |
|---|---|---|---|
| Millimeters | Nearest 32nd | Millimeters | Nearest 32nd |
| 2 | 3/32" | 55 | 23/16" |
| 2.5 | 3/32" | 60 | 29/16" |
| 3 | 1/8" | 65 | 23/4" |
| 4 | 5/32" | 70 | 23/4" |
| 5 | 3/16" | 75 | 31/8" |
| 6 | 1/4" | 80 | 31/8" |
| 8 | 5/16" | 85 | 33/8" |
| 10 | 13/32" | 90 | 39/16" |
| 12 | 15/32" | 95 | 33/4" |
| 14 | 9/16" | 100 | 315/16" |
| 16 | 5/8" | 110 | 45/16" |
| 18 | 23/32" | 120 | 43/4" |
| 20 | 25/32" | 130 | 51/8" |
| 25 | 1" | 140 | 51/2" |
| 30 | 13/16" | 150 | 57/8" |
| 35 | 13/8" | 160 | 66/16" |
| 40 | 19/16" | 170 | 611/16" |
| 45 | 13/4" | 180 | 71/16" |
| 50 | 2" | 190 | 71/2" |
Material Grade / Strength Chart
| American Bolts | ||||||
|---|---|---|---|---|---|---|
| Head Markings | Grade / Class | Material |
Size Range (Inches) |
Mechanical Properties | ||
|
Proof Load (PSI) |
Minimum Yield Strength (PSI) |
Minimum Tensile Strength (PSI) |
||||
 No Markings |
Grade 2 |
Low or Medium Carbon Steel |
1/4" to 3/4" | 55,000 | 57,000 | 74,000 |
| Over 3/4" to 11/2" | 33,000 | 36,000 | 60,000 | |||
 3 Radial Lines |
Grade 5 |
Medium Carbon Steel Quenched & Tempered |
1/4" to 1" | 85,000 | 92,000 | 120,000 |
| Over 1" to 11/2" | 74,000 | 81,000 | 105,000 | |||
 6 Radial Lines |
Grade 8 |
Medium Carbon Alloy Steel Quenched & Tempered |
1/4" to 1" | 120,000 | 130,000 | 150,000 |
|
Stainless markings vary Most stainless is non-magnetic |
18-8 Stainless |
Steel Alloy with 17-19% Chromium & 8-13% Nickel |
1/4" to 5/8" | -- |
40,000 Min 80-90,000 Typical |
100,000 - 125,000 Typical |
| 3/4" to 1" | -- |
40,000 Min 45-70,000 Typical |
100,000 | |||
| Above 1" | -- | 80-90,000 Typical | ||||
| Metric Bolts | ||||||
 8.8 |
Class 8.8 |
Medium Carbon Steel Quenched & Tempered |
All sizes through 11/2" |
85,000 | 92,000 | 120,000 |
 10.9 |
Grade 10.9 |
Alloy Steel Quenched & Tempered |
All sizes through 11/2" |
120,000 | 130,000 | 150,000 |
|
Stainless markings vary Most stainless is non-magnetic |
A-2 Stainless |
Steel Alloy with 17-19% Chromium & 8-13% Nickel |
1/4" to 5/8" | -- |
40,000 Min 80-90,000 Typical |
100,000 - 125,000 Typical |
| 3/4" to 1" | -- |
40,000 Min 45-70,000 Typical |
100,000 Typical |
|||
| Above 1" | -- |
80-90,000 Typical |
||||
|
Tensile Strength: The maximum load in tension (pulling apart) which a material can withstand before breaking or fracturing. Yield Strength: The maximum load at which a material exhibits a specific permanent deformation Proof Load: An axial tensile load which the product must withstand without evidence of any permanent set. |
||||||