"Size","Pitch (coarse)","Head Ø dk max","Head height k","Hex key s"
"M3","0.5","5.5","3","2.5"
"M4","0.7","7","4","3"
"M5","0.8","8.5","5","4"
"M6","1","10","6","5"
"M8","1.25","13","8","6"
"M10","1.5","16","10","8"
"M12","1.75","18","12","10"
"M14","2","21","14","12"
"M16","2","24","16","14"
"M18","2.5","27","18","14"
"M20","2.5","30","20","17"
"M22","2.5","33","22","17"
"M24","3","36","24","19"
"Reference only — confirm against drawing. ISO 4762 · DIN 912. REL India"