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Drill rubbing and not cutting
(a) Possible Cause
Too little lip clearance behind the cutting edge.
Solution
Check that the lip clearance is as per information on page 24/
25.
Cracks in cutting edges
(a) Possible Cause
The point is overheated and cooled too quickly when re-
sharpening.
Solution
Use coolant when grinding or grind in stages, quenching
frequently in soluble oil.
Rough hole finish
(a) Possible Cause
The drill is blunt.
Solution
Re-sharpen as per information on page 24/25.
(b) Possible Cause
Inadequate supply of coolant to the point.
Solution
The coolant must reach the point of the drill.
Drill breaks at flute runout
(a) Possible Cause
The workpiece moves during drilling.
Solution
The workpiece must be securely clamped.
(b) Possible Cause
The flutes are clogged with swarf.
Solution
Clear the flutes by frequently withdrawing the drill, or use a drill
more suited to the material e.g. a UDL drill for aluminium.
(c) Possible Cause
Using the wrong type of drill e.g. using a jobber drill for thin
material.
Solution
See pages 6 to 9 for the correct drill to suit the application.
