Hammer Trouble

Hammer Trouble Shooting
Problem Probable Fault Corrective Action
Hammer will not start Low Pressure Increase Compressor discharge pressure, use Booster Compressor
Incorrect Hammer Assembly Check Hammer Assembly
Dirty Hammer Clean Hammer
Damaged Components Overhaul Hammer
Intermittent Operation Worn Components, faulty Valve, Damaged Drill Bit or Drive Sub Overhaul Hammer
Dirty Hammer Clean Hammer
Too much down pressure Set the down pressure until the rotation starts to bind, then back off the down pressure until the hammer rotates smoothly
Rotation speed too slow Percussion Drill bit rotational speed of between 300mm and 400mm per second. Place chalk mark on drill string and check the advance vs the rotation. If the Drill string advance more than 12mm per rotation increase the rotation until the advance is 10mm per rotation.
DTH Hammer will not stop Hammering Plugged Bit or Inner Tube Lift hammer off bottom and blow air down. If still continuous hammer inspect inner tube and Percussion bit for blockages.
Worn Piston Measure the Large diameter of the piston, if air leaks past this it can cause the hammer to fire.
Too much water injection Reduce water injection
Check Valve not sealing Broken Check valve spring Replace check valve spring
Damaged check valve Check urethane face and internal seal, replace if worn or damaged
Low penetration/ Low Pressure Worn internal components Inspect piston, piston case and inner tube. Measure diameters and replace if clearance is greater than 1/2mm between bearing surfaces.
Lack of lubrication Ensure an oil film is coming from bit splines. (place cardboard under hammer to check)
Thread Damage to Top Cylinder or Drive Sub Hammer not correctly torque up prior to Drilling Refer Make up torque table (Page 24)
Incorrect breakout location. Refer breakout location.
Piston Galling Lack of lubrication Ensure an oil film is coming from bit splines. (place cardboard under hammer to check)
Piston Cracked Lack of lubrication Ensure an oil film is coming from bit splines. (place cardboard under hammer to check)
DTH Hammer badly bogged which can cause piston case to distort causing heat checks and cracks Flood tool with water when badly bogged
Using breakout wrench over wrong areas can cause piston case to distort which can initiate heat checks in piston Use breakout wrench in the approved areas only
Problem Probable Fault Corrective Action
Piston strike face cracking Not enough down force Increase down pressure until rotation binds and then back off until rotation and pressure become smooth.
Contamination from excess or acidic water causes pitting in the piston face Avoid excessive water during Drilling operation. Only use pH neutral water free from contamination.
Damaged Percussion bit Ensure strike face of percussion bit is not damaged.
Crack in Piston Case Excessive external wear Measure diameter of piston case.
Heat or weld applied to piston case Replace—never use heat on piston case.
Drive Sub cracked down spline Incorrect down pressure Increase down pressure until rotation binds and then back off until rotation and pressure become smooth.
Damaged Percussion Bit Splines Check percussion bit splines for damage; repair or replace
Tapered wear on Drive Sub Splines Not enough down force Increase down pressure until rotation binds and then back off until rotation and pressure become smooth.
Percussion Bit splines burred Check percussion bit splines for damage; repair or replace