I’m looking for help with maintaining the precise center location of holes as I enlarge them. I’m a violin maker. In creating the holes for tuning pegs and the end button, the locations are critical to proper function. The center point is laid out and marked with an awl, then progressively larger bits are used to get the holes large enough to accept the tapered reamer that finishes the job. The problem is that, particularly with highly flamed maple, the drill bits tend to bore slightly eccentrically as the size increases (probably because of variable hardness or grain directions) so that the location has shifted a little by the time the largest bit has done its job. It seems to me that the perfect tool for this job would be a stepped drill bit with a small diameter guide pin at the business end that could follow a pilot hole exactly and then having a step up to the final bored diameter (4 to 5 mm) something like the bit used for Kreg pocket hole jigs. The bits that come with the Kreg system are too large in diameter for this application (3/8″). Because the work piece is a nearly finished instrument, I don’t think there’s a practical way to clamp it to a drill press table-the drilling needs to be done by hand. Any ideas? Thanks