Question

Explain why screws are right-handed. What true synergy occurs when driving a screw?

Answer 1

The right handed thumb screws follows the principle of grip rule. By common convection, right handedness is the default handedness for screw threads. The hands supinate in opposite directions, your right hand supinates in a clockwise direction while your left hand supinates in an anti-clockwise direction. This means that you can drive a right handed screw with your right hand using your supinator and bicep, while your left hand would only be able to use the pronator muscles. Hence, a right handed screw can be driven in with the greatest strength when using your right hand.