Page 392 - THREADING CATALOG

USER GUIDE
TAPS Troubleshooting

Problem Cause Solution
incorrect tap (cutting geometry unsuitable for application) use tap selected from the relevant material group
faulty alignment ensure that the tap is correctly aligned with the core hole axis
Tapped hole improve lubrication and direction of
oversized tap jamming
coolant adjust cutting speed
incorrectly reground tap (lead tip is not concentric) regrind tap
incorrect tap (cutting geometry incorrect for application) use a tap from the relevant material group
check feed rate programming and/or pitch of leading
Stripped threads spindle speed and feed rate are not synchronized
spindle. use a tapping spindle with axial float (gti/gtin)
insufficient starting pressure exerted on tap (causes peeling) increase starting pressure
Bell mouthed incorrect starting pressure use a tapping spindle with axial float (gti/gtin)
tapped hole
incorrect tap (cutting geometry unsuitable select tap for the relevant material group
for application)
Unsatisfactory
thread surface the tap is blunt replace or regrind tap
finish tap badly re-ground regrind tap. check that cutting geometry is suitable for material

incorrect lubricant, concentration or quantity ensure the use of a suitable coolant and an ample supply
swarf jamming check cutting speed. use alternative tap
tap has jammed against bottom of pre-hole check hole and thread depths. drill a deeper pre-hole
Partial chipping
of tap tap incorrectly reground (lead-in diameter too ensure that correct dimensions are maintained when regrinding
short, therefore too few cutting teeth)
irregular workpiece material structure adjust cutting speed. improve lubricant quality of coolant
incorrect cutting speed adjust cutting speed to suit workpiece material
coolant lacking in lubricating qualities ensure the use of a suitable coolant and an ample supply.
Excessive tap wear and/or quantity check that the coolant is reaching the cutting zone
check pre-hole drilling conditions (drill carefully to reduce
surface of the pre-hole is compacted
risk of surface compacting). check drill cutting edges
incorrect tap in use (cutting geometry unsuitable for application) use tap from the relevant material group

centering error ensure that axes of tap and pre-hole are aligned
blunt tap regrind tap
Tap breakage
use tapping spindle with axial float and
tap has reached bottom of pre-hole
slipping clutch (GTI/GTIN)
pre-hole too small check for correct pre-hole size, see pages 379-381

ISCAR
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