Screw cheese head, set screw, head diam 3/8in, 1/4 in x 1in Whitworth Zinc Plated, Norton rocker box inspection cover, each. 1938-1947. 6 required 1936; 7 required 1937+ Orig part number 8897; A3/93 - rocker box cover screw [1936 to 1947]