The T-DRILL method was developed in the 1970s. The idea that
pipes and tubes could be branched much more quickly and cost-
effectively into end products of greater strength and higher
quality was as revolutionary as it was simple, and one of the
major inventions in the field. As the tee is fabricated from the
basic tube, no costly T-pieces are needed. Instead of three
joints there is only one joint! This saves a lot of time and
means considerably lower total costs. The construction also
makes the tube stronger and provides for better flow
characteristics. Pipe branching - i.e. connecting a branch pipe
to a run pipe - using T-DRILL method is also called collaring.
The joint can be completed by brazing (= lap joint) or by
welding (butt joint). For the lap joint process, a round hole is
drilled in the pipe wall using a collaring head. After the tube
wall is penetrated, two forming pins are extended from the drill
bit. The collaring head then automatically withdraws from the
main run pipe and forms a collar in rea