HEAD MARKING SHALL BE RAISED OR DEPRESSED (.O10 MAX.) AND ARRANGED AS FOLLOWS:
MARK WITH MANUFACTURER'S SYMBOL OR TRADEMARK, LENGTH DASH NUMBER AND RECESS
NUMBERS ENCIRCLED. RECESS NUMBER TO BE APPROXIMATELY 25% LARGER THAN OTHER NUMBERS.
MARK WlTH BASIC PART NUMBER ("NAS" OPTIONAL) EXCEPT MARK .1640-32 WITH "8"