Thread cutting - Knowledge
During thread cutting, especially the geometry of the tap is crucial, as each material has a different chipping behavior and the use of a wrong tool may lead to cold welding, chip jamming in flutes or tool break.
More information: Nomenclature, geometry and definitions of taps
Cutting speeds and lubrication / cooling
To increase the lifetime of the tools and keep the quality of the thread high, it is important to choose the cutting speed and cooling correctly.
More information: Cutting speeds and lubrication/cooling
Chamfer
The chamfer of the tap influences the distribution of the torque to the tool and the the tool life. Too high torque can cause a tool break. The longer the chamfer, the lower the torque and the force acting on the tool. In addition, the tool is better centered and easily guided into the core hole by a longer chamfer.
More information: Types of lead-in chamfers
Troubleshooting guide for tapping
| Tapping undersized threads | - Pitch error - Too small tolerance - Geometry of the tap is not suitable for the material |
|---|---|
| Tapping oversized threads | - Cutting speed is too high - Bad running accuracy - Chip jammings in flutes - Incorrect positioning of workpiece or tap - Inconsistent feed of tap - Too high tolerance |
| Poor thread surface | - Cutting speed not suitable - Cooling is not suitalbe or not existing - Geometry of the tap is not suitable for the material - Core hole too small |
| Thread break of the thread to be cut | - Geometry of the tap is not suitable for the material - Core hole too small - Core hole not deep enough - Chip jammings in flutes - Bad running accuracy - Incorrect positioning of workpiece or tap - Inconsistent feed of tap |
| Low tap lifetime | - Cutting speed not suitable - Cooling is not suitalbe or not existing - Geometry of the tap is not suitable for the material - Surface treatment/ coating for tap needed - Core hole too small |
| Tool outbreaks | - Geometry of the tap is not suitable for the material - Core hole too small - Core hole not deep enough - Chip jammings in flutes - Bad running accuracy - Incorrect positioning of workpiece or tap - Inconsistent feed of tap - Worn tap |
| Cold welding on the tap | - Cutting speed not suitable - Increase coolant supply |
Formulas
