Question 68 QMED02 - Electrician-Refrigerating Engineer

The Correct Answer is D. The primary function of a square shank on a heavy-duty screwdriver is to **allow turning with a wrench** (Option D). When a screw is seized, corroded, or requires exceptionally high torque, the user can slip an open-end or adjustable wrench onto the square section of the shank. This provides extra leverage beyond what the handle alone can provide, enabling the application of significant torque necessary to loosen or tighten stubborn fasteners. ### Why Other Options Are Incorrect: * **A) permit striking with a hammer:** While some heavy-duty screwdrivers (like cabinet or engineer's screwdrivers) are designed for striking, the striking force is meant to be applied directly to the end of the handle, often reinforced with a steel cap or tang that runs through the handle (a "through-tang"). The square shank is positioned further down the shaft near the handle and is not designed as the striking surface. * **B) prevent the shank from bending:** Although square stock is inherently very strong, the primary structural integrity and resistance to bending come from the overall diameter and material properties of the steel used. Round shanks of equivalent diameter and material are generally strong enough for standard heavy-duty use. The square shape is an added functional feature for torque application, not primarily a Bending Stress Mitigation feature. * **C) allow it to be used as a pry bar:** While a sturdy screwdriver can sometimes be misused as a small pry bar, this action is strongly discouraged as it can chip the tip, damage the blade, or cause the tool to fail. The square shank does not specifically enhance the tool's effectiveness or safety for prying; its purpose remains focused on rotational force (torque).