Occasionally we get asked how to convert shaft alignment angularity values expressed as mils (thousandths) per inch to degrees. Since mils per inch are the rise over run that means that the conversion to an angle is the arctangent. Or the conversion from an angle is the tangent of that angle.
Remember to include the decimals when converting so 1 mil/1 inch = .001″/1 inch.
| Angularity in mils/inch | Angle in degrees | Angle in Radians |
| 0.1 | 0.006 | 0.0001 |
| 0.2 | 0.011 | 0.0002 |
| 0.3 | 0.017 | 0.0003 |
| 0.4 | 0.023 | 0.0004 |
| 0.5 | 0.029 | 0.0005 |
| 0.6 | 0.034 | 0.0006 |
| 0.7 | 0.04 | 0.0007 |
| 0.8 | 0.046 | 0.0008 |
| 0.9 | 0.052 | 0.0009 |
| 1 | 0.058 | 0.001 |
| 1.1 | 0.063 | 0.0011 |
| 1.2 | 0.069 | 0.0012 |
| 1.3 | 0.074 | 0.0013 |
| 1.4 | 0.08 | 0.0014 |
| 1.5 | 0.086 | 0.0015 |
| 1.6 | 0.092 | 0.0016 |
| 1.7 | 0.097 | 0.0017 |
| 1.8 | 0.103 | 0.0018 |
| 1.9 | 0.109 | 0.0019 |
| 2 | 0.116 | 0.002 |
| 2.1 | 0.12 | 0.0021 |
| 2.2 | 0.126 | 0.0022 |
| 2.3 | 0.132 | 0.0023 |
| 2.4 | 0.138 | 0.0024 |
| 2.5 | 0.143 | 0.0025 |
| 2.6 | 0.149 | 0.0026 |
| 2.7 | 0.155 | 0.0027 |
| 2.8 | 0.16 | 0.0028 |
| 2.9 | 0.166 | 0.0029 |
| 3 | 0.172 | 0.003 |
| 3.25 | 0.186 | 0.00329 |
| 3.5 | 0.201 | 0.0035 |
| 3.75 | 0.215 | 0.00375 |
| 4 | 0.229 | 0.004 |
| 4.25 | 0.243 | 0.00425 |
| 4.5 | 0.258 | 0.0045 |
| 4.75 | 0.272 | 0.00475 |
| 5 | 0.286 | 0.005 |
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