Single point counterbores are designed for concentrically boring out pre-drilled or cored holes prior to reaming or to counterbore a hole. Used in conjunction with the Type 49035 eccentric clamping collar these tools are able to finish the bore to size by virtue of the /-0.5mm adjustment provided by the collar. Use single point tools for guaranteed concentricity. Will continue to operate effectively at a maximum of 5 x D. High tool rigidity gives maximum accuracy. Plain (Type 49030)