Bostech Drilling identified the need for a more robust breakout tool than that afforded by welding a lug onto a rigid stilson handle attached to a hydraulic cylinder.
Stilsons have a reduced sectional area through the threaded tail on the hook. When overloaded this section fails releasing the considerable stored energy resulting from the component strain, and violently projects the released part of the hook into the distance or the any bodies standing in the path of its flight.
The design of the Bostech Breakout tool does not allow the significant amounts of energy to be stored as the tool has a much larger stressed section and as such doesn’t strain to the same extent. So when failure happens less energy is released and the tool fails benignly, without potentially projecting parts into the distance or bodies.
The Bostech tool is so strongly constructed that observed high pressure trials only resulted in the 4140 test pieces (38HRC) being peeled like an orange.
These tools are safe even if caused to fail. They grip much better than stilsons and are less prone to slipping.