An undercarriage of a belted or track-type machine includes a drive wheel rotatably mounted to the machine and a roller frame assembly pivotally mounted to the machine. The roller frame assembly includes at least one idler wheel and a number of guide rollers. Stationary shafts are mounted to the roller frame assembly and rotationally support the idler wheel and guide rollers. Mounting caps clamp the stationary shafts to the roller frame assembly. One or more fasteners fasten an end portion adjacent to the shaft engaging portion of the mounting cap in abutting contact with the roller frame assembly. A single fastener fastens the other end portion of the mounting cap to the roller frame assembly; however, the other end portion is spaced apart from the roller frame assembly. The abutting contact between the mounting cap and roller frame assembly minimizes flexure of the fasteners and movement of the shaft under moment loading.