US TAP AND DRILL BIT SIZE
| Head Marking | Class & Materials | Size Range (mm) | Mechanical Properties Proof Load (MPa) | Mechanical Properties Min. Yield Strength (MPa) | Mechanical Properties Min Tensile (MPa) |
|---|---|---|---|---|---|
 | Class 8.8 Medium Carbon Steel | Below 16mm 16mm-72mm | 580 600 | 640 660 | 800 830 |
 | Class 10.9 Alloy Steel | 5mm-100mm | 830 | 940 | 1040 |
 | Class 12.9 Alloy Steel | 1.6mm-100mm | 970 | 1100 | 1220 |
| Stainless Steel Markings Vary Usually stamped A-2 | A-2 Stainless Steel Alloy with 17-19% Chromium & 8-13% Nickel | Up to 20mm | - | 210 Min. 450 Typical | 500 Min. 700 Typical |