Problem 1: The Blue Tip (Overheating)
Symptom: The tip of the drill bit turns rainbow/blue/black.
Cause: Excessive RPM with no cooling. High Speed Steel (HSS) loses its hardness at around 600°C. Once it turns blue, the bit is permanently softened and useless. Check correct RPM.
- Solution: Lower your RPM (Speed). Increase your Pressure (Feed). Add cooling fluid or water.
Problem 2: Chipped Corners
Symptom: The outer corners of the cutting lips are chipped or worn round.
Cause: The bit is wobbling or the material is inconsistent (e.g., hitting rebar in concrete). Also caused by using a woodworking bit on metal.
- Solution: Use a drill press for stability. Switch to an SDS drill for concrete (Rotary Hammer).
Problem 3: Shank Failure
Symptom: The bit snaps near the chuck end.
Cause: Jamming. The flutes got clogged with debris (swarf), locking the bit in the hole while the machine twisted it. This is common in deep holes.
- Solution: "Peck Drill" (pull the bit out frequently to clear chips).
Problem 4: Carbide Tip Loss
Symptom: The carbide plate is missing from the steel body.
Cause: Thermal shock or bad brazing. If you pour cold water on a hot carbide bit, the thermal shock can crack the braze. Learn more about carbide brazing quality.
- Manufacturing Insight: Cheap drills use "Induction Brazing". High-quality drills use "Vacuum Brazing" or "Copper Brazing" which is much stronger.
