got a 91/30. rod will not screw in. dismounted the rifle from the stock and am looking at a 1/4" square metal "block" with a 1/16" vertical hole in the middle. is it threaded for a tool to facilitate removal? It "feels" like I am hitting some non-metalic object when I push a wire in lieu of the rod to the "block". Measurement tells me that I am at the face of the block. My question is . How can I remove the block so as to "clean" the female threads?