When specifying slots or pockets for traditional manufacturing equipment, which corner is preferred?

• A. Square
• B. Round
• C. Triangular
• D. Oval

Answer: (B)

Round corners are preferred because they make slots and pockets easier to manufacture and more reliable in use. The rounded interior, or fillet, lowers stress concentrations that can become crack initiation sites under loading, which improves durability. From a machining standpoint, standard cutting tools naturally leave a small radius at corners, and achieving a true sharp square corner would require extra passes, special tooling, or risk of burrs and poorer finishes. Round corners also simplify deburring and chip clearance, and they tend to extend tool life. Sharp square corners, or nonstandard shapes like triangular or oval corners, add complexity and are not as readily produced with conventional equipment.