What item should never be left in the lathe chuck?

• A. Chuck Key
• B. Spindle Key
• C. Chuck Guard
• D. Tool Bit

Answer: (A)

Safety first: never leave a chuck key in the lathe chuck. The chuck key is used to tighten or loosen the jaws, and once the spindle starts, the jaws grip anything in them. A loose key fits perfectly into the rotating chuck and can be hurled out at high speed, posing a serious risk of injury to you or others and potentially damaging the machine or workpiece. Always remove the key before turning on the lathe and store it in a designated spot or use a holder to remind yourself. The guard should stay in place for protection, and a tool bit belongs in the tool post only when actively cutting and should be removed when not in use.