The lathe tool shown as figure "R" in the illustration would best be used to __________. GS-0090

Correct Answer: Option C — form a right-cut square shoulder

Figure R is a side-facing tool designed to cut square shoulders. By positioning the cutting edge perpendicular to the axis of rotation, it allows the machinist to face the end of a workpiece or cut a clean, 90-degree shoulder against a larger diameter section of the shaft.