For slots or pockets in traditional manufacturing, which corner geometry is easier to machine?

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

Answer: (A)

The tendency in traditional milling is that a curved, round corner is easiest to machine. That’s because standard cutting tools have a nose radius, so forming a rounded interior corner fits neatly with a single, straightforward toolpath using a common end mill (for example, a ball-nose or corner-radius tool). This avoids the complications of sharp edges, which would require a tool with an almost zero radius or multiple operations to approximate true sharpness. Sharp or highly acute corners—like square, triangular, or pentagonal profiles—often demand extra passes, multiple tools, or special tooling to reproduce the geometry accurately, and they can cause tool chatter or clearance issues if approached with a simple, single-pass strategy. Round corners also improve chip evacuation and reduce stress concentration, making the pocket easier to finish cleanly with conventional machining.