How Screwdrivers Are Made? (Mega Factories Video)
A screwdriver includes an enlarged blade and a straight bit with parallel opposing surfaces. The surfaces apply torque to a screw slot over an increased area and reduce the tendency of the bit to slip out of the slot as compared to conventional commercially available screwdrivers. The screwdrivers are preferably made of hardened high quality steel so that they will be strong enough to withstand a substantial amount of torque.
A screwdriver is classified by its tip, which is shaped to fit the driving surfaces—slots, grooves, recesses, etc.—on the corresponding screw head. Proper use requires that the screwdriver's tip engage the head of a screw of the same size and type designation as the screwdriver tip. Screwdriver tips are available in a wide variety of types and sizes. The two most common are the simple 'blade'-type for slotted screws, and Phillips, generically called "cross-recess", "cross-head", or "cross-point".
Watch the video till the end to understand the whole process !