AAR Circular Letter C-9283

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February 21, 2001

Circular Letter

(c-9283)

 

Subject: Implementation of Revisions to Section H, Part II, Rule 3.19

TO THE MEMBERS AND PRIVATE CAR OWNERS                                                                                             File Number: TWBL-25.8

In Circular Letter c-9208, dated September 15, 2000, comments were solicited concerning proposed revisions to MSRP Section H, Part II, Rule 3,19.  The Wheels, Axles, Bearings and Lubrication Committee has reviewed all comments received and implemented the revision as presented below.  The revision is effective March 21, 2001.

RULE 3.19 Inspection of Inner and Outer Rings

Masters used in the calibration of gages for the measurement of inner ring inside diameters and outer ring counterbores should conform to American Gage Design Committee Standards and should be of at least Class X tolerance.  It is mandatory that the masters be certified at least every three (3) years by a qualified metrology laboratory against standards traceable to that National Institute of Standards and Technology and that up-to-date records of certification be maintained in each bearing repair facility.  Digital reading devices must be graduated in at least 0.0001" graduations.  Masters, gages, and the parts being gaged should be at the same temperature

This is your authority to update Section H, Part II, Rule 3.19.  These revisions will be included in the next revision of the manual.

Sincerely,

Thomas Stahura