the threaded top part 10 that screws into the bottom of the hydraulic cylinder 2 and the aperture 13 on each side of the shaft 6 through which the bolt 7 that secures the top tooth 4 in place extends fig9 is an exploded view of the shaft 6 and top tooth 4 of the present invention as shown in this figure the top tooth 4 comprises an extension 25 that fits up into the bottom end of the shaft 6 the extension 25 comprises an aperture 26 through which the bolt is inserted 7 after passing through the aperture 13 in the bottom end of the shaft 6 thereby securing the top tooth 4 to the shaft 6 although the top tooth 4 may be secured to the shaft with a bolt 7 as shown in this figure other mechanisms for securing the top tooth 4 to the shaft 6 such as a set screw may be utilized as well the top tooth 4 further comprises a cutting edge 27 which will come into contact with the rock during operation of the invention because the top tooth 4 is fixedly attached to the shaft 6 and the shaft 6 is fixedly attached to the hydraulic cylinder 2 the top tooth 4 will move up and down concurrently with the hydraulic cylinder 2 and shaft 6 fig1 is a perspective view of three different embodiments of the top tooth 4.