How to convert angularity in mils/inch to angles in degrees
"precision alignment"| Alignment tolerances
By Michael Keohane on January 9, 2014
Occasionally we get asked how to convert shaft alignment angularity values expressed as mils (thousandths) per inch to degrees. Since mils per inch is 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
|
|
About the Author
Michael KeohaneMike Keohane has been involved in machinery reliability since 1985. He started as a field service engineer for IRD Mechanalysis. Prior to that he was a wireline logger for Schlumberger Well Services. He joined VibrAlign in 1992 and supports clients in Georgia, South Carolina, Alabama and the Florida Panhandle. In addition to precision alignment, he has field experience in vibration analysis, field and shop balancing, oil analysis and ultrasonics. Mike holds a BSME from Michigan State University. Mike and his wife and two children currently live in Peachtree City, GA.
How many inches or mils. is a 19degree angle