by Mark V on Mar 28, 2014 at 9:34 AM
This is how they make the holes in Mavic Ksyrium SL rims and other similar rims where the nipples thread directly into the rim. It’s called friction drilling. Rather than having a metal bit that bites into the work piece and removes material in its path, friction drilling uses a fast-spinning conical bit that is pressed hard to the piece. The friction heats the material which flows out of the way of the bit. The friction drill bit must be made of a heat resistant material like cemented carbide (I mean, all good drill bits are made of heat resistant material, but this is way beyond cobalt steel). The advantage is that the process creates a hole with material left around the circumference; then that material can be tapped with threads for the spoke nipple.