Which rules apply when turning on the milling machine?

• A. Check speed range before turning on
• B. Check tool clearance before turning on
• C. Check tool direction when turning on
• D. All of the above

Answer: (D)

Before turning on a milling machine, you must verify all safety and setup conditions that affect how the machine will behave in motion. Checking the speed range ensures the spindle RPM matches the tool and the cut; the wrong speed can dull the tool, overheat the workpiece, or create dangerous chatter. Checking tool clearance ensures there’s no collision with clamps, fixturing, or the part—anything protruding into the path can cause breakage or kickback when the spindle starts. Checking tool direction means confirming the spindle rotation and feed direction are set correctly for the planned operation, which affects chip evacuation, cutting action, and the risk of tool or part interference as you begin motion. Since each check targets a different hazard and collectively covers the main startup risks, performing all of these is the safest and correct approach before turning on the machine.