Notes :

• Break sharp edge on head where spherical and conical surfaces meet.
• Where specifying nominal size in decimals, zeros preceding the decimals and in the fourth decimal place shall be omitted.
• “R” in the recess size tabulation means regular depth recess and the “S” means short depth recess.
• Square recesses incorporate a slight taper on the sides od the recess. This taper can result in loss of penetration gaging depth on finished fasteners due to the build up of plating in recesses. The recess penetrations dimensions specified here are for finished (plated) product. Manufactures should be advised that they should not use all this tolerance in the heading process, or an out of tolerance condition could exist after plating.