The tool has a crucial part to creation of the final product. The tool consists of two main functions: 
# Localized heating 
# Material flow
The tool at its most simplest form consist of a shoulder, a small cylinder with a diameter of 50 mm, and a pin, a small threaded cylinder similar to a drill. The tool itself has been modified to reduce displaced volume of the metals as they merged. Recently two new pin geometries have arisen:
# Flared-Triflute – introducing flutes (large carving vertically on the pin)
#A-skew – the pin axis being inclined to the axis of the spindle.