aperture 34 the oval aperture allows for variations in the relative distance between the locating protrusions 20 on blocks with the third embodiment illustrated in fig5 a 5c holder blocks with varying distances between the locating protrusions can be employed with this mounting plate the forward locating protrusion nearest the cutting bit is inserted into aperture 36 first and the second protrusion is then positioned in the oval aperture the width of the oval opening is manufactured to snugly guide onto the locating protrusion and the elongated length for the oval aperture permits for accommodating locating protrusions of different size in length and or spacing therebetween in fig5 a the minimum allowable spacing between the locating protrusions on the block 10 is shown as distance u201c c u201d and the maximum distance between the two protrusions is represented by u201c b u201d fig5 c best illustrates the alignment members as seen in fig5 c the alignment member 28 that corresponds to the aperture 36 is a complete ring however the alignment member 28 that extends from the oval aperture is in the shape of two symmetric crescents the two arcuate crescents are received in one cylindrical hole on a drum pedestal and the complete ring alignment member is received in a second cylindrical hole similar to the embodiment shown in fig1 3 the plate has a bottom surface 38 that is attached to the circumferential surface of the rolling drum the.