Machining troubleshooting guide
Start from the symptom to find likely causes and fixes (cutting conditions, tool, setup, coolant). Based on cutting-tool makers’ troubleshooting guides, with points that two or more makers agree on listed first.
In trouble?
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the symptom.
Turning and milling
Chatter (vibration)11 causes, 15 fixes Turning, MillingRough, torn, or fuzzy finished surface8 causes, 9 fixes Turning, MillingDimensions vary or are out of tolerance5 causes, 8 fixes Turning, MillingBuilt-up edge forms7 causes, 6 fixes Turning, Milling, Drilling, TappingChips stretch long or tangle5 causes, 6 fixes Turning, Milling, DrillingChips are too fine, scatter, or stick3 causes, 5 fixes TurningChips clog or jam (milling, end milling)6 causes, 6 fixes MillingBurrs appear (turning, milling)6 causes, 9 fixes Turning, MillingEdge chipping (workpiece edge breaks off)6 causes, 7 fixes Turning, MillingHeat generation is large (accuracy loss, shorter tool life)2 causes, 2 fixes TurningEnd mill breaks7 causes, 9 fixes MillingWalls lean or are wavy (end milling)5 causes, 6 fixes MillingPoor flatness or parallelism (face milling)3 causes, 3 fixes Milling
Tool damage (wear and chipping)
Flank wear is rapid6 causes, 7 fixes Turning, MillingLarge rake face wear (crater wear)5 causes, 4 fixes Turning, Milling, DrillingBoundary wear (groove-like wear at the depth-of-cut line)4 causes, 5 fixes Turning, MillingCutting edge chipping10 causes, 8 fixes Turning, MillingFracture (large chipping or cracking)6 causes, 6 fixes Turning, MillingWorkpiece material welds to the cutting edge6 causes, 6 fixes Turning, MillingThermal cracks4 causes, 6 fixes Turning, MillingPlastic deformation of the cutting edge4 causes, 4 fixes Turning, Milling, DrillingFlaking (peeling of the cutting edge surface)4 causes, 5 fixes Turning, Milling
Drilling
Hole becomes oversized (drilling)7 causes, 6 fixes DrillingHole becomes undersized (drilling)4 causes, 3 fixes DrillingHole bends or leans (poor straightness)6 causes, 6 fixes DrillingHole position shifts or hole is not round (rice-ball shape)6 causes, 6 fixes DrillingDrill breaks8 causes, 7 fixes DrillingBurrs at the hole exit (breakthrough)4 causes, 6 fixes DrillingChips clog (drilling)3 causes, 4 fixes DrillingDrill chipping (periphery, chisel edge)7 causes, 6 fixes DrillingDrill wears quickly (peripheral corner, margin, center)6 causes, 5 fixes DrillingRough hole inner surface (drilling)6 causes, 4 fixes Drilling
Tapping
Tap breaks11 causes, 10 fixes TappingThread is loose (internal thread oversized; no-go gauge goes in)7 causes, 7 fixes TappingThread will not go through (internal thread undersized; go gauge does not go in)6 causes, 6 fixes TappingThread is torn or galled6 causes, 7 fixes TappingTap teeth chip6 causes, 6 fixes TappingTap wears quickly or welds5 causes, 5 fixes TappingBurr or raised material at the entrance with a form (roll) tap1 causes, 2 fixes Tapping
Reaming
Material-specific problems
Stainless steel quirks (work hardening, welding, boundary wear)7 causes, 7 fixes Turning, Milling, Drilling, Tapping, ReamingAluminum alloy quirks (welding, built-up edge, chips)6 causes, 6 fixes Turning, Milling, Drilling, Tapping, ReamingTitanium and titanium alloy quirks (heat, welding, ignition)7 causes, 7 fixes Turning, Milling, Drilling, Tapping, ReamingCast iron quirks (powdery chips, edge chipping, black scale)7 causes, 5 fixes Turning, Milling, Drilling, Tapping, ReamingHardened steel (high-hardness steel) quirks3 causes, 3 fixes Turning, Milling, DrillingHeat-resistant alloy (Ni-base alloy, etc.) quirks3 causes, 4 fixes Turning, Milling, Drilling, TappingMagnesium alloy quirks (chip ignition)2 causes, 2 fixes Milling, Drilling, Tapping, TurningCopper and copper alloy quirks3 causes, 2 fixes Turning, Milling, Drilling, Tapping, ReamingMild steel (low-carbon steel) quirks2 causes, 4 fixes Turning, Milling