Because they have no flutes, they are much stronger than conventional thread cutting taps and where used correctly result in greater tap life.
Due to the absence of swarf they also achieve much better blind hole characteristics without the associated chip removal problems. Higher than normal tapping speeds have been found to be advantageous and in some cases twice the normal recommended speed for thread cutting taps has been applied.
Better results have been achieved using lubricating oils rather than conventional cutting oils.
Cold forming, compared to cutting, produces threads with an unbroken grain structure and therefore much stronger. As a result the normally accepted 75% thread depth produced with thread cutting taps can be reduced to 60% depth without any loss of strength.
Note :
- This displacement of metal during cold forming has a tendency to upset the metal on the workpiece surface and counter-sinking of drilled hole is therefore recommended to eliminate interference between mating parts.
- Cold forming taps are not recommended where the wall thickness is less than 70% of the nominal tap diameter.
- Since the tapping drill size is based on metal deformation, the recommended tapping drill sizes for thread cutting taps do not apply to cold forming taps. For recommended sizes, contact GRIPCOIL technical sales.
