A-A-50503A
3.1.3 Pivots and bearings. Bearings shall be self-aligning and shall be hardened steel, ceramic, or polished agate. The pivot knife edges shall be sharp, straight, and shall be hardened steel.
Bearings shall be protected by dust covers or equivalent enclosures to minimize contamination and corrosion of the precision bearing surface.
3.1.4 Load receivers. Stainless steel load receivers shall conform to American Society for Testing Materials (ASTM) A 167, "Standard Specification for Stainless and Heat-Resisting Chromium-Nickel Steel Plate, Sheet, and Strip" (DoD adopted).
3.1.4.1 Style A. The load receiver for style A scales shall be stainless steel plate type and shall be 152 ± 13 mm in diameter. The plate shall be flat except that a raised peripheral lip not exceeding 7 mm in height will be acceptable.
3.1.4.2 Style B. The load receiver for style B scales shall be stainless steel pan type and shall be
152 ± 13 mm in diameter by 25 ± 7 mm in depth.
3.1.4.3 Style C. The load receivers for style C scales shall be scoop type, not less than 254 mm long, 152 mm wide, and 65 mm in depth. The scoops shall be stainless steel or break resistant polypropylene as specified in the acquisition order (see 7.4(c)).
3.1.5 Attachment weight set. Each scale shall be furnished with a set of attachment
counterpoise weights consisting of one 500 gram and two 1000 gram weights. Each weight shall be legibly marked to indicate the equivalent load capacity.
3.1.6 Cover. A translucent or opaque plastic fitted cover shall be furnished with each scale.
3.1.7 Tare weight assembly. When specified in the contract or acquisition order (see 7.4(d)), a tare weight assembly shall be furnished with each scale. The tare weight assembly shall consist of a separate tare beam and poise or a tare counterpoise weight. The tare assembly shall be adjustable within a range up to at least 200 grams.
3.1.8 Specific gravity assembly. When specified in the contract or acquisition order (see 7.4(e)), a specific gravity assembly shall be furnished with each scale. The specific gravity assembly shall consist of a stand or counter clamp and rod for supporting the scale above the counter surface at a height of at least 254 mm.
3.2 Performance. The scales shall be designed to meet the applicable performance requirements and basic acceptance tolerances of National Institute of Standards and Technology (NIST) H44, "Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices". The scales shall be designed to support, without permanent deformation or misalignment, a 3260 gram load or a load equal to 125 percent of the nominal capacity, which ever is greater. The scales shall be capable of accurately registering weight indications regardless of repeated manipulation of any scale element, as in normal usage, including the following:
a. Repeated application and removal of maximum loads and attachment weights. b. Repeated operation of locking services.
c. Repeated displacement of all weight beam poises to the limit of each beam scale.
2
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business