What are the recommended pressure and air volume ranges for operating down hole hammer drills?

• A. Pressure: 50-125 psi; Volume: 100-300 CFM
• B. Pressure: 700-900 psi; Volume: 1500-2000 CFM
• C. Pressure: 150-500 psi; Volume: 250-1000 CFM
• D. Pressure: 10-50 psi; Volume: 20-60 CFM

Answer: (C)

Down hole hammer drills rely on a careful balance of air pressure and the amount of air delivered. The compressed air provides the impulse to drive the hammer, while the air flow (CFM) clears cuttings and cools the tool. If the pressure is too low, the hammer won’t deliver enough impact energy and may stall; if it’s too high without enough flow, you can overstress the tool or waste energy. The range of 150-500 psi with 250-1000 CFM covers a wide range of hammer sizes and rock conditions, ensuring sufficient impact energy and adequate air to clear debris and cool. The other options either don’t supply enough energy or propose pressures and flows that are excessive or impractical for typical down hole hammer operation.