The die collar, also known as skirted taper tap, is a special external fishing tool that engages
with the dropped tubular objects such as drill pipes and oil tubing, by tapping on the external
wall of the objects. It can be used in fishing cylindrical objects without inner bore or stuck inner
bore.
The die collar is a long cylindrical integral structure composed of a Sub, a Tap body with cutter
threads in the cone shaped interior. The die collar is made of high strength alloy with cutting
grooves in the fishing threads.