This SAE Metric Aerospace Standard (MA) specifies the drawing requirements for center holes when center holes are required on the finished part.

Application:

Center holes make it possible to install a part between bench or machine centers in the process of manufacturing. With such center holes, it is possible to:

a. Achieve center related runout requirements

b. Simplify manufacture and inspection of some revolution generated parts, namely those featuring multiple concentric diameters requiring several machining operations

Dimensional Standards:

Dimensions and tolerances in this standard are expressed in millimeters and comply with those for Type A center holes per ISO 866 and Type B center holes per ISO 2540.