Pierce nut system - for cost-efficient joints

Bulten’s BUFO® self-clinching pierce nut system offers several advantages in terms of in-place cost, working environment and productivity.

Introducing a pierce nut assembly system involves everything from feeding system to stamping equipment, press integration and the nut itself.

Bulten offers a complete pierce nut system including the machinery, nuts and technical support needed to maximise productivity and ensure a quality controlled assembly line.


Compared to weld nut, the pierce nut has the following advantages:

  • Saves electricity
  • No smoke
  • No weld splatter, which eliminates re-tapping of the nut
  • Avoids intermediary steps between the pressing and welding stations
  • Reduces lead times
  • Avoids difficulties with coated sheet metal
  • More secure orientation of the nut against sheet metal and a more exact right-angle, thus avoiding misassembly such as positioning.


In comparison to square pierce nuts, there are also further advantages:

  • Easier feeding and less risk of the nut getting stuck in the feeding system
  • More even distribution of pressure between nut and sheet metal
  • No stress concentrations due to sharp corners
  • Reduced risk of stress cracks in the sheet metal


If an unthreaded pierce nut will be combined with thread rolling screws, such as taptite®, a further reduction of In Place Cost is achieved, thanks to:

  • Eliminates risk of cross threading
  • Not necessary to plug or mask the nut hole
  • Not necessary to clean threads after painting or other surface treatment
  • A more vibration resistance joint is obtained
  • Additional locking features are not needed


Another advantage of the bulten system for round pierce nut is the use of a gas spring when mounting the nut. This system gives the following advantages:

  • Controlled setting force
  • Optimal torsional resistance
  • Optimal pull through force
  • Optimal push out force
  • Allows generous stamping process window compensation



Mounting the pierce nut is a straight forward, one step process. The nut, forced by the punch, makes its own hole through the sheet metal and the die ensures a solid attachment of the pierce nut.



Head office

Bulten AB
Box 9148
400 93 Gothenburg, Sweden

Visitor's address:
August Barks gata 6A, Gothenburg

Tel: + 46 31 734 59 00
Fax: + 46 31 734 59 39