Bores and Keyways for Flexable Couplings, Metric Series.

ANSI/AGMA 9112-B15

ANSI/AGMA 9112-B15

This standard presents metric dimensions, tolerances, sizes and fits for straight bores, tapered bores, keys and keyways for unmounted industrial flexible couplings. The keys and keyways followed the recommendations of ISO R773:1969 and shaft tolerances followed ISO R775:1969. Shaft keyseat dimensions and tolerances were given in ISO R773:1969. This specification includes index tolerances for multiple keyways.

Inspection methods for straight and tapered bores and keyways are included in the annexes. The annexes also include the recommended design practice for tapered shafts for use with flexible couplings.

This standard is applicable to couplings as defined in ANSI/AGMA 9009-D02, Flexible Couplings - Nomenclature for Flexible Couplings, with metric bores and keyways.

This standard does not apply to: 

  • couplings attached to shafts without keys, see ANSI/AGMA 9103-B08;
  • couplings attached to shafts with tapered bushings or keyless shaft locking devices;
  • shafts and bores with tapered keys;
  • inch bores with metric keyways;
  • metric bores with inch keyways;
  • metric bores with metric keyways; or
  • shaft keyseat tolerances. 

See ANSI/AGMA 9002-C14 for inch bores with inch keyways.

[The foreword, footnotes and annexes, if any, in this document are provided for informational purposes only and are not to be construed as a part of ANSI/AGMA 9112-B15, Cylindrical Bores and Keyways for Flexible Couplings (Metric Series).]

This standard incorporates information from the following International Organization for Standardization (ISO) and American National standards Institute (ANSI) standards:

  • ISO 286-1, ISO System of limits and fits - Bases of tolerances, deviations and fits;
  • ISO 286-2, ISO System of limits and fits - Tables of standard tolerance grades and limit deviations for
  • holes and shafts;
  • ISO R773 (withdrawn 1998), Rectangular or Square Parallel Keys and their Corresponding Keyways;
  • ISO R775 (withdrawn 1998), Cylindrical and 1/10 Conical Shaft Ends;
  • ANSI/AGMA 9002-C14, Bores and Keyways for Flexible Couplings (Inch Series).

The intent of this document is to offer designers and users of flexible couplings preferred dimensions, tolerances and fits for metric bores and keyways. ANSI/AGMA 9112-B15 describes sizes and tolerances for straight and tapered bores and associated keys and keyways, as furnished in metric flexible couplings.

This standard incorporates a small portion of the numerous variations of shaft/bore fits. These fits and tolerances have been determined to be the preferred fits and tolerances that most closely relate to the bore and keyway fit classes from ANSI/AGMA 9002-A86. A study of the existing metric standards indicated that the many possible combinations of shaft/bore fits would be impractical to adopt as an all-encompassing standard. Therefore, this standard does not intend to replace any existing metric standards, but to define what is preferred. Note that this standard is a pure metric standard, and not a metric conversion of ANSI/AGMA 9002-C14 (Inch Series).

In AGMA 9112-B15 the “measurement of bores” section was moved from an annex to clause 4, now becoming a part of the standard. Bores are to be measured prior to cutting the keyway.

The first draft of ANSI/AGMA 9112-B15 was made in April, 2011. It was approved by the AGMA membership in January 2015. It was approved as an American National Standard on February 4, 2015.

The following standard contains provisions which, through reference in this text, constitute provisions of this American National Standard. At the time of publication, the edition indicated was 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 edition of the standard indicated below.

  • ANSI/AGMA 9009-D02, Flexible Couplings - Nomenclature for Flexible Couplings

Reaffirmed December 2020

ISBN: 978-1-61481-092-6 

Pages: 42

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