This document specified the main dimensions and tolerances which affect interchangeability between end yoke earwork for the most common North American-used universal joints. Dimensions and tolerances of the mating universal joints are left to the discretion of the universal joint manufacturers.

The term "earwork" refers to the configuration and geometry defining end yoke connections directly provided for universal joint cross attachment of drivelines.

Earwork for certain styles of universal joint connections and flange connections have for a long time been proprietary to certain manufacturers. Over years of usage, proprietary rights have expired and the industry, as a whole, has used these earworks as standard. In an effort to tabulate some of the long-established practices, the following SAE Recommended Practice has been compiled. Manufacturers do from time to time, as the need arises, change tolerances or fits to better enhance component performance. This document has been prepared as a reference, and is a snapshot of current technology.

The half round (strap connection), full round (retainer plate type connection), and wing type connection are covered in this document. For an understanding of these end yoke styles, please refer to SAE J901.

There are earwork forms that still are proprietary and are not covered by this document.