Question 54

The Correct Answer is C ### Why Option C (blade from overheating) is Correct When cutting metal, especially with a power hacksaw, significant friction is generated between the saw blade and the workpiece. This friction produces intense heat. Excessive heat causes the blade to lose its temper (hardness), rapidly dulling the cutting teeth and severely shortening the life of the blade. In extreme cases, overheating can even cause the blade to warp or break. The primary function of a coolant (or cutting fluid) in this context is to **dissipate this heat**, thus keeping the blade and the cutting zone cool, preserving the blade's sharpness, and improving the quality of the cut. ### Why the Other Options are Incorrect **A) cut from clogging:** While cutting fluids do help flush chips away (which reduces clogging), this is a secondary benefit. The primary and most critical function is thermal management (cooling). Furthermore, power hacksaws, due to their reciprocating motion and generally slower speeds compared to processes like milling or drilling, are less prone to severe clogging issues that would halt the operation, provided the chips are reasonably cleared. **B) blade from catching on the work piece:** The likelihood of a blade catching on the workpiece is primarily determined by factors such as the feed pressure, the shape and angle of the teeth, the workpiece clamping stability, and the clearance angle. Coolants do not directly prevent the mechanical action of "catching." **D) blade from bending:** Blade bending is usually caused by excessive or uneven feed pressure, improper blade tensioning, or a lack of rigidity in the machine setup. While an extremely hot blade might be slightly weaker, the coolant's main purpose is not to address the mechanical forces that cause bending, but rather the thermal stress.