Application Guide Troubleshooting - HSS Drills
1
Problem
1 Breaking of drill
2 Outer corner breaks down
3 Cutting edges chip
4 Drill splits up centre
5 Drill will not enter work
6 Hole rough
7 Hole oversize
8 Tang breaks
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5
6
7
8
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450
Possible Reason Solution
Dull point Sharpen
Drill has front taper due to wearing Sharpen
Insufficient lip clearance on point Grind correctly
Lip clearance too great Regrind to correct clearance angle
Drill in incorrectly point ground Regrind correctly
Flutes clogged with chips Remove drill from hole and
to clear flutes
Spring or backlash in drill press,
fixture or work Check each item for rigidity
and alignment
Feed too heavy Reduce Feed
Cutting speed too high Reduce speed
Dry cutting, no lubricant at
cutting edges Apply cutting fluid
Drill web (core) diameter too big Thin web to original size
Fixture/Clamping not rigid Secure job firmly
Unequal angle or uneven length
of cutting edges Regrind to same lip lengths
and angles
Spindle run-out/Loose spindle Check machine
Bad fit between shank taper & socket. The
drive & alignment is controlled by the taper fit Remove dirt, nicks or burrs, or
replace worn socket
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