Rotation is clearly the most effective, efficient and least expensive way to remove industrial studs or bolts.

The objective is to grip a stud and through the proper use of torque, start the rotation process.

The truer the rotational circle, the less friction will be applied to the threads of the stud and the housing.  This is one of the reasons impact wrenches are used.  There is no side loading with impact wrenches.  Sometimes, hydraulic wrenches are also used.  Impact wrenches also utilize harmonics in breaking the bind between the threads.  The hammering effect of the impact wrenches vibrates the stud and creates these harmonics, which assist in removal.

The StudPuller is designed with two opposing jaws that ride on two opposing cams.  These cams are placed into the tool as two eccentric circles.

When the two jaws rotate internally on the two cams, they are designed to create a concentric circle at both the major and minor diameters of the stud.  Two eccentric circles create one concentric circle that is the very diameter of the stud being removed. 

That concentric circle is the key to the science of the StudPuller.  While it is possible that multiple jaws could be used to accomplish this task, two jaws have proven to be the most effective design.  The jaws actually “grip” the stud.  This grip allows for a pure rotation of the stud out of the housing.  Anything other than pure rotation impedes stud removal.

Tool and jaw hardness: because of the hardness of studs, StudPuller jaws are hardened to 55RC, which is harder than most studs.  This causes the jaws to slightly bite into the stud, giving it the grip necessary to secure the stud to the tool body.  The cages and tool bodies are also hardened with a QPQ coating that penetrates the surfaces of the cage and the tool.

The Swarf: TRW calls the two opposing cams a “swarf.”  The angles and dimensions of this swarf are precisely engineered, along with the cage and jaws, to rotate simultaneously and in synch with each other.  The jaws are floating inside the cage and riding on the swarf.  As the tool is rotated counterclockwise, the jaws actually stay in their original position while the tool itself is rotating around the cage and jaws.  As the jaws ride up the cam in tandem, they begin to approach and make contact with the stud.  This is the very point of the new concentric circle, which is aligned with the concentric circle of the stud.  The jaws are then locked onto the stud and the entire tool, with the stud firmly gripped, begin to rotate.  As torque is applied, the mechanical bind begins to loosen, eventually releasing the stud for extraction or removal.  TRW challenges anyone involved in stud removal to show better science than this.  Pure rotation is the ultimate in stud removal through rotation.  The Original StudPuller is easily the most productive tool on the market."