Trepanning head is also named as annular drill, it is an economic, productive and high quality deep hole tool. Its productivity is more than 10 times the ordinary drill. It is better to use trepanning tool for machining the hole above 50mm in diameter. This tool is applicable to the following conditions:

(1) Hole diameter is 50mm above, and with the close tolerance on straightness and position precision.

(2) The length-to-diameter ratio of the hole is in the range of 1-75, it is the better choice to use trepanning head than other machining methods.

(3) The job material is very expensive and the core needs measuring and chemical analysis, and the entire core mandrel needs to be reserved.

(4) The machine power is not enough if drilling the big hole, so the trepanning is the good choice, It is suitable for the diameter ranged from 50 to 600mm (the matching tool bar should be also deployed).