Flexible Couplings - Keyless Fits (Metric Edition)

ANSI/AGMA 9103-C17 (Errata included)

ANSI/AGMA 9103-C17 (Errata included)

Errata included on last page.


This standard presents information on design, dimensions, tolerances, inspection, mounting, removal, and equipment that is in common use with keyless tapered and keyless straight (cylindrical) bore hubs for flexible couplings. Calculated hub stress values and hub to shaft torque capacities are nominal values. This standard does not present a rigorous analysis of the components.

This Standard applies only to hubs and solid shafts made of steel, which generally have material properties of modulus of elasticity equal to 2.0
7 × 105 MPa, density equal to 7830 kg/m3, and thermal expansion coefficient equal to 11.4 × 10-6 mm/mm/ºC.

This standard does not apply to couplings attached to shafts with keyways, splines, split hubs or polygon


This standard was developed after intensive study of existing practices, standards and literature. The intent of this document is to offer to rotating equipment designers and users a standard for design practice and dimensions regarding keyless fits for flexible couplings. In general, the information in this standard is a consolidation of the most common practices and standards currently in existence. This AGMA standard and related publications are based on typical or average data, conditions, or applications.

Work was begun on ANSI/AGMA 9103-A91 in 1985 and was approved by the AGMA membership in February 1991. It was approved as an American National Standard on May 20, 1991. ANSI/AGMA 9103-B08 split the original standard into inch and metric versions (ANSI/AGMA 9103-B08), updated Annex B and added an example calculation as Annex D.

The first draft of ANSI/AGMA 9103-B08 was made in October 2004. It was approved by the AGMA membership in October 2007. It was approved as an American National Standard on May 20, 2008.

ANSI/AGMA 9103-C17 provides a revised description of the effective hub to shaft engagement length, and Figure 5c has been deleted as a result. The first draft of ANSI/AGMA 9103-C17 was made in August 2016. It was approved by the membership in November 2017 and as an American National Standard on December 6, 2017.

The following standards contain provisions which, through reference in this text, constitute provisions of
this American National Standard. At the time of publication, the editions indicated were valid. All
standards are subject to revision, and parties to agreements based on this American National Standard
are encouraged to investigate the possibility of applying the most recent editions of the standards
indicated below.

  • ANSI/AGMA 9112-B04, Bores and Keyways for Flexible Couplings (Metric Series)
  • ANSI/AGMA 9009-D02, Flexible Couplings – Nomenclature for Flexible Couplings

Reaffirmed August 2022

ISBN: 978-1-64353-001-7

Pages: 35

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