I used this with a template I milled out of aluminum for a neck pocket for an electric guitar. The bit cut aluminum shavings so the bit didn't exactly work with the bearing. Perhaps I expected too much - the accuracy of the machine from a wood drill, but the machined pocket turned out to be too large. I need to wrap the bag in a piece of veneer so it's quite functional and I don't regret the purchase. Perhaps the bit available from Stuart McDonald would have been more accurate, but I needed aβ¦