3a thread class right-hand 4.0300" overall length 1.0932" bore diameter 20 thread quantity per inch shaft has a spherical bottom holewhich is 0.3800 in. in diameter, and is 1.8800 in. deep; it also has a chamfer that measures 0.0600 in. with a 45 degree angle; item used on B1b acft shouldered flange type unjef thread series