Final Answer:
The part on a pair of shears that controls the moveable or action blade is option d. tension screw.
Step-by-step explanation:
The option d.tension screw is a critical component in shears that regulates the movement of the blades. It is located at the pivot point, and adjusting the tension screw controls the tightness or looseness of the blades. The tension screw ensures that the blades have the appropriate amount of resistance, allowing for smooth and precise cutting.
Proper tension is vital for achieving optimal performance and longevity of the shears. If the tension is too tight, it can cause excessive wear on the blades and make cutting difficult. On the other hand, if the tension is too loose, the blades may not meet properly, leading to uneven cutting and potential damage to the shears. Therefore, the tension screw serves as a key mechanism for maintaining the functionality and effectiveness of the shears.
In conclusion, the tension screw is a crucial element in shears, providing engineers and professionals with the ability to fine-tune the performance of the tool. Understanding and adjusting the tension screw appropriately ensures that the shears operate smoothly and efficiently, contributing to their overall effectiveness in various applications.