A raise drill having a central drive stem to which a surrounding cutter mounting frame is attached, the cutter mounting frame supporting a plurality of rotary cutter units. One or more inboard cutter units each include a shaft and a rotary cutter journaled for rotation on the shaft. One end of the shaft is inserted in a bore extending into the side of the stem. A yoke member receives the outer end of the shaft. The yoke member is supported by a mounting block secured to the frame. The mounting block has first and second intersecting planar surfaces, the first surface extending substantially parallel to the axis of the bore and the second surface extending in an obtuse angle to the first surface facing the stem. The yoke member has a first surface which slidably engages the first surface of the mounting member, and a second surface spaced from the second surface of the mounting member, allowing axial movement of the cutter shaft into and out of the bore. A spacer or shim is inserted between the second surfaces after the shaft is inserted in the bore and bolts extending between the yoke and the mounting block pull the yoke against the mounting block and at the same time clamp the spacer in place.