| If You See This… | Likely Cause | Adjust This… | Why It Works |
|---|---|---|---|
| Dust or powder instead of chips | Feed rate too low, RPM too high (rubbing not cutting) | ➕ Increase Feed Rate ➖ Reduce RPM | Increases chip load so the tool actually cuts, not polishes. |
| Long, stringy chips | Feed rate too high or poor chip evacuation | ➖ Reduce Feed Rate ➕ Improve chip clearance (air blast, upcut bit) | Prevents overheating and tool stress. |
| Burn marks or smoke | RPM too high or feed too low | ➖ Lower RPM ➕ Increase Feed Rate Improve cooling | Reduces heat buildup and rubbing. |
| Bit breaks or dulls quickly | Feed too fast, depth too deep, poor rigidity | ➖ Reduce Feed Rate ➖ Reduce Depth of Cut Check tool sharpness and clamping | Lowers tool load and vibration. |
| Chatter or vibration sounds | Tool deflection, workpiece loose, wrong speed/feed ratio | ➖ Reduce Depth/Step-over ➕ Increase Feed Slightly Secure workpiece, shorten tool stick-out | Stabilizes cutting forces and harmonics. |
| Tear-out or fuzzy edges (wood) | Wrong cutter type or direction | Use Down-Cut or Compression Bit ➕ Increase RPM Slightly | Shears fibers cleanly instead of pulling them. |
| Dull, gray, or discolored chips (metal) | Excessive heat or dull tool | ➖ Reduce RPM ➕ Apply coolant Replace or resharpen bit | Keeps temperature in proper range. |
| Tool leaves ridges or poor finish | Feed too high, tool deflecting, or worn bit | ➖ Reduce Feed Rate ➖ Reduce Step-over Check runout or replace tool | Ensures smoother passes and tighter tolerance. |
| Squealing or whining sound | Too high RPM or rubbing | ➖ Lower RPM ➕ Increase Feed Rate | Brings chip load into optimal range, reducing friction. |