①,The diameter of the unthreaded body shall not be more than the maximum major diameter nor less than the minmum pitch diameter of the thread. ②,For screw lengths four times the major diameter or less, thread length shall extend to within two threads of the head bearing surface. Screws of greater length shall have comlete threads for a minimum of four major diameters. ③,Screws shall be free of all projecting burrs, observed at 3x magnification. |