Problems & solutions for drilling with diamond core bits
Problems & solutions for drilling with diamond core bits

Problems & solutions for drilling with diamond core bits

The core will not drill
• The material is too hard for the core bit application range: use a specification suitable for the material in question
• The diamond impregnation is blunt: sharpen the tool with a grinding stone or abrasive material
• Speed too high: reduce speed
• Water flow too high: reduce water flow
• Excessive play of the drilling stand guides: set up the drilling stand correctly, or have it repaired
• Drilling stand not properly anchored: improve anchoring, use suitable dowels and a thread rod
• Insufficient machine power: check the motor speed and slip-clutch. Use a more powerful drill
• Drill motor running, but core bit not rotating: low contact pressure so that the slip clutch is not engaging. If the problem reoccurs, have the drill repaired

Excessive wear of the diamond segments
• Insufficient flow of water. Drilling sludge sharpens the diamonds and also wears them down: increase the water flow
• Feed / contact pressure too high: reduce feed
• Drilling material is very abrasive: use a harder core bit segment specification
• Excessive motor power: adjust the motor speed to reflect the core bit diameter
• Core drilling system has too much play, causes excessive vibrations: check and correct the settings. Tighten screws, effect repairs as needed
• The drill stand is not properly anchored: improve anchoring, use adjusting screws (make sure they are adjustable). Use the right dowels and threaded rods for the material that you are drilling

High level of core bit barrel wear
• The core drilling system is not sufficiently anchored on the substrate: improve anchoring, use the adjusting screws. Use dowels and threaded rods
• Water flow too low: increase water flow
• Core drilling system has too much play (vibrations): check and correct all settings. Tighten screws. If needed, renew damaged parts of the drill or drill stand
• Core bit not correctly seated in the motor chuck: check the chuck for damage. Is the core bit correctly aligned with the motor axis?
• Slanting in case of hand held machines: avoid slanting
• Motor shaft not turning smoothly: check drill motor, if needed readjust or repair
• Drilling is mainly in abrasive material or dry: check the core bit and the water supply
• Metal pieces causing friction in drill hole: remove residues from drill hole. Temporarily increase the coolant flow to clean the drill hole

Diamond segments breaking or working loose
• The core bit and its segments are overheated (insufficient or no water cooling): observe sufficient cooling. Remove diamond segments from drill hole
• Pronounced vibrations during drilling: adjust the core drilling system and ensure correct anchoring
• The core bit has taken some knocks in the drill hole (loose reinforcement, hard pebbles, tubes, segments that have come loose): thoroughly clear out any residues from the drill hole to avoid more damage. Break out the core, temporarily drill a smaller diameter, or drill a larger diameter
• Excessively abrupt start to drilling: allow the core bit to slowly work its way into the material until the segments are cutting along their complete circumference. Then proceed at the recommended feed speed
• Core bit has been dropped: take care during handling and transport - do not drop the core bit

Core jammed in the core bit
• The core is jammed due to insufficient cooling water or loose parts (wire ends, rubber or similar): unscrew the core bit and carefully tap with a piece of wood. Push the parts through the cooling water opening in the core bit using a metal rod
• Water flow too low: increase water flow
• Loose parts (e.g. lateral bars, reinforcement, rubber residue, wire ends) are causing the core bit to jam. Release the core bit from the machine and carefully remove the parts left in the core bit. Take care not to damage the segments
• Lateral stress in hand held applications: use the machine's linear guide or a drill stand if needed
• The diamond segments no longer have clearance: Check the clearance (the diamond segments must protrude beyond the core bit barrel on the inside and outside). Use a new core bit if needed

Cracks in the core bit barrel
• Pronounced vibrations during drilling: adjust the core drilling system and ensure correct anchoring
• Loose parts in the core bit are preventing smooth running: remove the loose parts from the core bit
• Core bit barrel walls are too thin: replace the core bit

Segments are bent inward or outward
• Play in individual core drilling system components: adjust the core drilling system
• The core drilling system is not sufficiently anchored on the substrate: ensure correct anchoring
• Core bit hitting the substrate: exercise more care
• Core bit hitting loose reinforcements: remove the loose reinforcements