Troubleshooting Guide
PROBLEM
CAUSE
SOLUTION
Inappropriate spindle speed Reduce spindle speed Possible work hardening of pre-drilled hole Prevent work hardening of pre-drilled hole Inappropriate thread relief Use proper thread relief Inappropriate chamfer length Adjust chamfer length
Premature Tap Wear
Change coolant method Increase volume / concentration Apply surface coating / treatment
Inappropriate lubrication
Welding / Galling
Inappropriate spindle speed
Reduce spindle speed
Change coolant method
Increase volume / concentration
Inappropriate lubrication
Apply surface coating / treatment
Deformed Lobes
Possible work hardening of pre-drilled hole Prevent work hardening of pre-drilled hole Inappropriate spindle speed Reduce spindle speed Inappropriate pre-drill size Increase pre-drill hole size as much as possible
Change coolant method Increase volume / concentration Apply surface coating / treatment Improve wear resistance of tap
Inappropriate lubrication
Tap substrate not suitable for material
Possible chip packing
Avoid chip packing
Tap Breakage
Inappropriate pre-drill size Inappropriate spindle speed Possible runout or tapered hole Too high of torque generated
Increase pre-drill hole size as much as possible
Reduce spindle speed
Reduce runout and assure hole is straight
Use compensating tension / compression tap holder Adjust feed rate appropriately Check CNC program Use compensating tension / compression tap holder Adjust feed rate appropriately Check CNC program Use tap holder with torque adjustment / limiting feature Avoid hitting the bottom of the hole, check stroke length, alignment and hole size
Possible tap collision with bottom of hole
Overcutting / Oversized Threads
Inconsistent feed of spiral fluted style tap
Inconsistent feed of spiral pointed style tap
Tearing on Flanks
Inappropriate thread relief / rake angle
Use sharper / freer cutting relief and angle
Change coolant method Increase volume / concentration Apply surface coating / treatment Select appropriate cutting conditions Select appropriate cutting conditions
Inappropriate lubrication
Extremely Torn Threads
Possible welding / galling Possible chip packing Inappropriate thread relief
Use sharper thread relief
Change coolant method Increase volume / concentration Apply surface coating / treatment
Inappropriate lubrication
Chips Remain at Bottom
Reduce chamfer relief angle Use thinner land width Reduce chamfer length Reduce cutting angle
Inappropriate geometry of tap
795
Threading Technical
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