GGG-B-121B

Abstract

This specification covers requirements for sine bars, plates, and fixtures. They are for use in inspection and layout work. <br>Federal specifications do not include all varieties of the commodity as indicated by the title of the specification, or which are commercially available, but are intended to cover only those generally used by the Federal Government. <br>Sine bars, plates, and fixtures covered by this specification shall be of the following types, grades, and classes, as specified (see <a>6.1</a>): </span><pre> Type I.&#8212;Sine bars. Grade A.&#8212;Laboratory. Class 1.&#8212;Lapped. Class 2.&#8212;Ground. Grade B.&#8212;Commercial. Class 1.&#8212;Lapped. Class 2.&#8212;Ground. Type II.&#8212;Sine plates. Grade A.&#8212;Laboratory. Class 1.&#8212;Lapped. Class 2.&#8212;Ground. Grade B.&#8212;Commercial. Class 1.&#8212;-Lapped. Class 2.&#8212;Ground. Type III.&#8212;Sine bar fixtures. Grade A.&#8212;Laboratory. Class 1.&#8212;Lapped. Class 2.&#8212;Ground. Grade B.&#8212;Commercial. Class 1.&#8212;Lapped. Class 2.&#8212;Ground. Type IV.&#8212;Sine plate fixtures. Grade A.&#8212;Laboratory. Class 1.&#8212;Lapped. Class 2.&#8212;Ground. Grade B.&#8212;Commercial. Class 1.&#8212;Lapped. Class 2.&#8212;Ground.</pre> <br> <br>Size of sine bars, plates, and fixtures shall be 5 inches, 10 inches, or 20 inches, as specified (see <a>6.1</a>), except that special lengths may be specified (see <a>3.10</a>). <br>