Define feed in machining.

• A. The speed of the spindle.
• B. The distance the tool advances per revolution (or per tooth in milling).
• C. The depth of cut per pass.
• D. The total length of the cut.

Answer: (B)

Feed is the rate at which the cutting tool advances through the workpiece. It describes how far the tool moves relative to the work for each rotation of the spindle (in turning) or for each tooth engagement (in milling). This is commonly expressed as inches per revolution (IPR) or millimeters per revolution, and as feed per tooth in milling. Spindle speed, on the other hand, refers to how fast the spindle rotates, not how fast the tool advances. The depth of cut per pass tells how deeply the tool bites into the material in one pass, while the total length of the cut is about the overall travel distance, not the incremental advancement per rotation.