Plastic Deformation

• Excessive heat in cutting zone
• Wrong grade
• Inadequate coolant supply
• Depth of cut too large
• Cutting speed too high
• Nose radius too small

• Reduce RPM/reduce depth of cut/check turned dia.
• Use coated grade/use harder grade
• Apply coolant
• Reduce depth of cut /increase no. of passes
• Reduce cutting speed
• If possible use insert with larger radius

Premature Wear

• Cutting speed too high
• Infeed depth too small
• Highly abrasive material
• Inadequate coolant supply
• Wrong inclination anvil
• Wrong turned dia. prior to threading
• Insert is above center line

• Reduce RPM
• Modify flank infeed /increase depth of cut
• Use coated grade
• Apply coolant
• Reselect anvil
• Check turned dia.
• Check center height

Insert Breakage

• Wrong turned dia. prior to threading
• Wrong Grade
• Poor chip control
• Incorrect center height

• Check turned dia.
• Use tougher grade
• Change to M/B type inserts and use modified flank infeed
• Check center height

Built-up Edge

• Cutting edge too cold
• Wrong grade
• Inadequate coolant supply
• Incorrect cutting speed

• Increase RPM /increase depth of cut
• Use coated grade
• Apply coolant
• Change cutting speed

Vibration

• Incorrect workpiece clamping
• Incorrect tool setup
• Incorrect cutting speed
• Incorrect center height

• Use soft jaws
• Check tool overhang / use anti vibration bars
• Increase cutting speed
• Check center height

Poor Surface Finish

• Wrong cutting speed
• Excessive heat in cutting zone
• Poor chip control
• Inadequate coolant supply
• Wrong inclination anvil
• Tool overhang too long
• Incorrect center height

• Increase/reduce RPM
• Reduce depth of cut
• Modify flank infeed
• Apply coolant
• Reselect anvil
• Reduce tool overhang
• Check center height

Poor Chip Control

• Excessive heat in cutting zone
• Wrong grade
• Inadequate coolant supply
• Wrong turned dia. prior to threading
• Incorrect method of infeed

• Reduce RPM /change depth of cut /check turned dia.
• Use coated grade /check turned dia./use M/B type inserts
• Apply coolant
• Check turned dia.
• Modified flank infeed 3-5°

Thread Profile is Too Shallow

• Incorrect center height
• Worn insert
• Insert isn’t machining the tread crest
• Excessive wear

• Check center height
• Change to new cutting edge sooner
• Check the workpiece dia.
• Increase radial infeed

Broken Nose During First Pass

• Cutting edge too cold
• Depth of cut too large
• Wrong grade
• Wrong turned dia. prior to threading
• Incorrect center height
• Infeed depth too shallow
• Wrong inclination anvil
• Tool overhang tool long

• Increase RPM
• Reduce depth of cut/increase number of infeed passes
• Use tougher grade
• Check turned dia.
• Adjust center height
• Modify flank infeed
• Reselect anvil
• Reduce tool overhang

Incorrect Thread Profile

• Unsuitable thread profile
• Incorrect center height
• Incorrect pitch in the program

• Adjust to correct tool ,anvil and insert
• Adjust center height
• Change the program

Flank Wear

Cause	High cutting speed
Remedy	Reduce cutting speed
Cause	Chip too thin
Remedy	Increase feed rate and reduce radial passes
Cause	Insufficient coolant
Remedy	Check coolant pressure / flow direction

Fracture/Chipping

Cause	Vibration
Remedy	Check stability
Cause	High load on cutting edge
Remedy	Reduce feed rate Add radial passes

Build up Edge

Cause	Cutting speed too low
Remedy	Increase cutting speed
Cause	Insufficient coolant
Remedy	Check coolant pressure / flow direction

Thread Surface-Chatter Marks/Vibrations

Cause	Feed rate is too high
Remedy	Reduce feed rate
Cause	Large profile
Remedy	Add passes
Cause	Thread length too long
Remedy	Add radial passes Reduce overhang

Thread Accuracy (GO/NOGO Gauge)

Cause	Tool deflection
Remedy	Reduce feed rate Add radial passes Use ZERO compensation
Cause	CNC program error
Remedy	Check CNC program

Insert/Tool Breakage

Cause	High load on the cutting edge
Remedy	Add radial passes
Cause	Unproper cutting conditions
Remedy	Adjust cutting conditions
Cause	Chip evacuation
Remedy	Add sufficient coolant
Cause	CNC program error
Remedy	Check CNC program

Tapered Thread

Cause	Tool cutting load
Remedy	Add radial passes and/or reduce cutting conditions
Cause	Tool overhang
Remedy	Clamp tool to the minimum overhang length

Short Tool Life

Cause	Unsuitable cutting conditions
Remedy	Adjust feed/speed
Cause	Vibrations
Remedy	Reduce overhang as short as possible Check tool and workpiece clamping