Page 64 - HOLE MAKING CATALOG p311-382

TAPS USER GUIDE

Troubleshooting

Problem Cause Solution
Tapped hole 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
oversized Improve lubrication and direction of coolant
Tap jamming Adjust cutting speed
Regrind tap
Incorrectly reground tap (lead tip is not concentric)
Incorrect tap (cutting geometry incorrect for application) Use a tap from the relevant material group

Stripped threads Spindle speed and feed rate are not synchronized Check feed rate programming and/or pitch of leading
spindle. Use a tapping spindle with axial float (GTI/GTIN)

Bell mouthed Insufficient starting pressure exerted on tap (causes peeling) Increase starting pressure
tapped hole Use a tapping spindle with axial float (GTI/GTIN)
Unsatisfactory Incorrect starting pressure
thread surface Select tap for the relevant material group
Incorrect tap (cutting geometry unsuitable Replace or regrind tap
finish for application) Regrind tap. Check that cutting geometry is suitable for material
The tap is blunt
Tap badly re-ground

Incorrect lubricant, concentration or quantity Ensure the use of a suitable coolant and an ample supply

Swarf jamming Check cutting speed. Use alternative tap

Partial tap Tap has jammed against bottom of pre-hole Check hole and thread depths. Drill a deeper pre-hole
chipping Ensure that correct dimensions are maintained when regrinding
Tap incorrectly reground (lead-in diameter too
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

Partial tap Tap has jammed against bottom of pre-hole Check hole and thread depths. Drill a deeper pre-hole
chipping Ensure that correct dimensions are maintained when regrinding
Tap incorrectly reground (lead-in diameter too
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

Excessive Coolant lacking in lubricating qualities Ensure the use of a suitable coolant and an ample supply.
tap wear and/or quantity Check that the coolant is reaching the cutting zone

Surface of the pre-hole is compacted Check pre-hole drilling conditions (drill carefully to reduce
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

Tap breakage Blunt tap regrind tap
Tap has reached bottom of pre-hole
Use tapping spindle with axial float and
slipping clutch (GTI/GTIN)

Pre-hole too small Check for correct pre-hole size, see pages 364-365

374 ISCAR