flush (flat) countersunk (included angle - less than 135 deg w or w/o chamfer) head style 0.563" grip length ns" letters after the material code "b" indicate no preference to lock type (may be visible or internal) . rivets with no letter code (indicating visible lock type)
right-hand nut thread 22.2mm nut thread thread length 46.55mm overall length shoulder with extended washer 17.6 max dia by 1.3 mm min thk zinc surface treated shouldered m stud thread thread series