INCH-POUND
A-A-57174A
July 20, 2010
SUPERSEDING
A-A-57174
September 17, 1992
COMMERCIAL ITEM DESCRIPTION
NUT, CAP, DUAL WHEEL MOUNTING
The General Services Administration has authorized the use of this commercial
item description as a replacement for MS53068C for all federal agencies.
1. SCOPE. This commercial item description covers dual wheel mounting cap, nut, which is
used to mount and secure dual wheels on the vehicle's axle.
2. SALIENT CHARACTERISTICS.
2.1 Material. The nut, cap shall be made of low carbon steel (carbon content 18 to 35%) and
case hardened to a surface hardness of Rockwell 15N-85.5 minimum and to a depth of 0.005 to
0.012 inches or made from alloy steel that are through hardened to produce a core hardness
reading of Brinell 227-277 and a surface hardness reading of 15N-78-84.
2.2 Protective finish. The surface shall be zinc plated per ASTM B633, Type II, class SC3
(Fe/Znl2), except for the inner threads which are not fully plated. Hydrogen embrittlement relief
shall be done within one hour after plating.
2.3 Design and construction. The nut, cap shall be designed and constructed in accordance with
figure 1 and shall be capable of sustaining a proof load of 44,000 pounds (lb) without failure or
permanent set. The proof load shall be verified in accordance with the following test procedure
or other equivalent test:
a. Engage a 3/4-16 threaded hardened mandrel into nut, cap using 10 to 12 threads.
b. Thread cap, nut into a hardened fixture engaging 6 to 8 of the 1 1/8-16 outer threads.
c. A 44,000 lbs tensile force shall be loaded axially through the threads and maintained
for 15 seconds.
Beneficial comments, recommendations, additions, deletions, clarifications, etc. and any data that
may improve this document should be sent to DAMI_STANDARDIZATION@conus.army.mil or
U.S. Army RDECOM, Tank Automotive Research, Development and Engineering Center,
ATTN: RDTA-EN/STND/TRANS MS #268, 6501 E. 11 Mile Road, Warren, MI 48397-5000.
Since contact information can change, you may want to verify the currency of this address
information using the ASSIST Online database at https://assist.daps.dla.mil/online/.
AMSC N/A
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