This reamer holder is unique in that you can adjust the reamer to enter the bore of the barrel by adjusting the three thumbscrews. Once adjusted in, the reamer is supported for no drag withdraw and plunge of the reaming operation. The tension springs give a constant force to the reamer to stay seated on the dead center in the tailstock. The holder comes with the dead center.The greatest advantage is the 360Adeg. hold on the reamer. Ever try to tap a straight hole by turning and holding onto one handle of a tap handle? The same thing happens when reaming. The reamer tips 90Adeg of applied pressure and the pilot rides hard on the top side of the rotating bore.Radial alignment is corrected with this reamer holder. Axial alignment is not. The axial displacement in the ram of the tailstock will provide what is needed. That is if the correct alignment procedure has been performed to the lathe and tailstock for reaming operations, i.e. chambering for rifles! Tailstock alignment procedure...