Screwdrivers don't have a round head, because a round head has no torque at all. The word is to guarantee torque, and the cross allows the force to be distributed more evenly. According to the power source, there are manual screwdrivers and electric screwdrivers; according to the batch head or the cutter head, there are a flat head and a cross (phillips).
Tèt yon tournevis ki gen bon kalite -ki fèt ak asye prentan ak yon dite relativman wo. Yon bon tournevis ta dwe difisil men pa frajil, ak difisil ak difisil. Lè ouvèti a nan tèt vis la vin chòv ak glise, ou ka frape tournevis la ak yon mato fè Groove nan vis la pi fon, pou ke vis la ka devise fasil. pa pliye. An jeneral, li espere ke dite nan tèt la tournevis pi gran pase HRC60, epi li pa fasil rouye.
