Page 79 - Aluminum_Machining_catalog_2023

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
Oversized tap jamming improve lubrication and direction of 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 Tap
Chipping 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
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 Tap
Chipping 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 and/or quantity check that the coolant is reaching the cutting zone
Tap Wear
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 67-68

77