Goldo Triple Edge Countersink, 1/4"

The Göldo 1/4" (6.3mm) Triple Edge Countersink (MFG# WS63S) is a high-quality countersink bit used for beveling screw holes and enlarging potentiometer holes that are too narrow (like when switching from metric to US-spec pots that require a larger hole).  To enlarge holes, simply drive the countersink as far into the hole as necessary.