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AAR Circular Letter C-9284 |
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AAR Circular Letter C-9284 |
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February 21, 2001
Circular Letter
(c-9284)
Subject: Implementation of Revisions to Section G, Part II, Rule 1K4
TO THE MEMBERS AND PRIVATE CAR OWNERS File Number: TWBL-22.24
In Circular Letter C-9209, dated September 15, 2000, comments were solicited concerning proposed revisions to MSRP Section G Part II Rule 1K4. The Wheels, Axles, Bearing and Lubrication Committee has reviewed all comments received and implemented the revision as present below. The revision is effective March 21, 2001.
Rule 1K4 Axle journal, journal fillet and dust guard seat must be cleaned with a wire brush or other suitable means. Journal diameters on new, secondhand or reclaimed axles must be checked for proper size and journal ends for upset condition (Figure 4.10). Dial or digital snap gage (with 0.0001 scale) must be used to measure journal diameter and must be calibrated using the master disc (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 the National Institute of Standards and Technology and that up-to-date records of certification be maintained in each wheel shop facility. Master gages must be the same temperature as the axle being measured unless appropriate compensation is made for the temperature difference between the master disc and the journal being measured. Check for proper fillet with fillet gage (Figure 4.11) to insure proper seating of backing ring. Excessive galling or fretting of the fillet will require scrapping or reworking the axle, in accordance with established dimensional allowances. Axle ends must be clean and free of dirt and contaminants. Visually inspect tapped holes in the axle ends for thread damage, dirt and corrosion.
This is your authority to update Section G Part II Rule 1K4. These revisions will be included in the next revision of the manual.
Sincerely,
Thomas Stahura