A-A-52531 Kingpin, Fifth Wheel, 2 Inch And 3.5 Inch, UniversalThis CID covers the requirements for a universal kingpin used in coupling military trailer to a truck-tractor or a trailer converter dolly fifth wheel. It also includes the requirements for kingpins used in trailers when transported on flat cars.

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A-A-52531

Part Identification Number

Former MS part no.

AA52531-1

MS53038-1

NOTES:

1. Unless otherwise specified, all radii shall be 0.125 inch.

2. Dimensions are in inches. Dimensions indicated by pound sign (#) shall be in accordance with SAE J700 and J848.

3. Heat treat: Oil quench and temper to a surface hardness of 443-512 BHN over all areas of kingpin.

4. The use of asterisks (*) indicates that dimensions are covered by international agreement (see 6.5).

5. Unless otherwise specified, tolerances are + 0.015; + 1E on angular dimensions.

6. Unless otherwise specified, machined surfaces shall be 125 or better, according to

ANSI/ASME B46.1 (see 6.1.2).

FIGURE 1. Kingpin, fifth wheel, 2 inch and 3.5 inch, universal.