What must be true of lathe centers to achieve a true cylindrical form?

• A. They must be ground
• B. They must be sharpened
• C. They must be replaced
• D. They must be lubricated

Answer: (A)

Lathe centers must be ground to achieve a true cylindrical form because grinding produces a precise, concentric geometry with a smooth, accurate center point and bearing surfaces. This exactness keeps the workpiece aligned with the spindle axis, minimizing runout and eliminating wobble or taper as it turns. Sharpening can create irregularities in the center geometry, leading to eccentricity, while lubrication helps reduce friction but cannot correct geometric inaccuracies. Replacing parts or other tweaks don’t inherently guarantee the precise geometry required for a true cylinder.