An external hex screw head is also referred to as a hex head cap screw. The screw head is produced up of the 6-sided fastener. There are several combination-style screw heads using a slotted screw head from the Center of your hex head cap. How are types of screws categorised? https://dantezbzxu.mybloglicious.com/50448875/types-of-screw-heads-for-screwdrivers-for-dummies