Portable Drill Safety Precautions
Check carefully for loose power cord connections and frays or damage to the cord. Replace damaged tool and extension cords immediately.
Be sure the chuck is tightly secured to the spindle. This is especially important on reversible type drills.
Tighten the bit securely as prescribed by the owner/operator's manual. The chuck key must be removed from the chuck before starting the drill. A flying key can be an injury-inflicting missile.