The charts every counter, quality lab, and maintenance shop keeps taped to the wall — free, original, and printable. Based on published ASME and SAE standard data. Always verify critical applications against the governing standard.
| Size | UNC (coarse) TPI | UNC Tap Drill | UNF (fine) TPI |
|---|---|---|---|
| #4 | 40 | #43 | 48 |
| #6 | 32 | #36 | 40 |
| #8 | 32 | #29 | 36 |
| #10 | 24 | #25 | 32 |
| 1/4 | 20 | #7 | 28 |
| 5/16 | 18 | F | 24 |
| 3/8 | 16 | 5/16 | 24 |
| 7/16 | 14 | U | 20 |
| 1/2 | 13 | 27/64 | 20 |
| 9/16 | 12 | 31/64 | 18 |
| 5/8 | 11 | 17/32 | 18 |
| 3/4 | 10 | 21/32 | 16 |
| 7/8 | 9 | 49/64 | 14 |
| 1 | 8 | 7/8 | 12 |
| Size | Pitch (mm) | Tap Drill (mm) |
|---|---|---|
| M3 | 0.5 | 2.5 |
| M4 | 0.7 | 3.3 |
| M5 | 0.8 | 4.2 |
| M6 | 1.0 | 5.0 |
| M8 | 1.25 | 6.8 |
| M10 | 1.5 | 8.5 |
| M12 | 1.75 | 10.2 |
| M14 | 2.0 | 12.0 |
| M16 | 2.0 | 14.0 |
| M20 | 2.5 | 17.5 |
| M24 | 3.0 | 21.0 |
| Grade / Class | Head Marking | Min Tensile | Typical Use |
|---|---|---|---|
| SAE Grade 2 | No radial lines | 74 ksi (to 3/4") | General purpose, low stress |
| SAE Grade 5 | 3 radial lines | 120 ksi (to 1") | Automotive, machinery |
| SAE Grade 8 | 6 radial lines | 150 ksi | High-strength, drivetrain |
| Class 8.8 | "8.8" on head | 800 MPa | Metric standard structural |
| Class 10.9 | "10.9" on head | 1040 MPa | Metric high-strength |
| Class 12.9 | "12.9" on head | 1220 MPa | Socket cap screws, tooling |
| Bolt Dia. | Wrench Size | Bolt Dia. | Wrench Size |
|---|---|---|---|
| 1/4 | 7/16 | 9/16 | 13/16 |
| 5/16 | 1/2 | 5/8 | 15/16 |
| 3/8 | 9/16 | 3/4 | 1-1/8 |
| 7/16 | 5/8 | 7/8 | 1-5/16 |
| 1/2 | 3/4 | 1 | 1-1/2 |
| Size (UNC) | Grade 5 | Grade 8 |
|---|---|---|
| 1/4-20 | 8 | 12 |
| 5/16-18 | 17 | 24 |
| 3/8-16 | 30 | 45 |
| 7/16-14 | 50 | 70 |
| 1/2-13 | 75 | 110 |
| 5/8-11 | 150 | 220 |
| 3/4-10 | 260 | 380 |
Torque values are approximate for dry, unlubricated, plain-finish fasteners and vary with plating, lubrication, and joint design. For critical joints, calculate from the actual application or test. Reference only — not engineering advice.
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