Minor carpentry projects occasionally induce reflections upon one's tools. In this case, the reflection is upon Black & Decker's "Pilot Point" drill bits. Substance of said reflection being that while they perform very well and cut very clean holes very quickly, they are difficult to resharpen, and they are a poor choice for enlarging an existing hole¹. This latter fact is rather annoying at the moment, as I have four 7/16" blind holes that I need to enlarge uniformly to 1/2".
(Well, 31/64" would be better, actually ... for this purpose, a slight interference fit is desirable.)
In this case, as it happens, aside from the fact that the peg holes were originally drilled blind, there was no particular reason why they needed to be blind holes, and I needed to deepen them slightly anyway for teh replacement pegs, which would have left them within about 3/16" of being clear holes all the way through the rail. What's more, from the drilled side, the original pilot made a nice center spot for a new drill. So I just drilled through the center of each hole to the back with a 3/32" drill, then drilled them out to 31/64" from the back using the 3/32" hole to pilot the 31/64" drill. A quick spin of the countersink bit both sides to chamfer the hole edges, a light touch with the orbital sander, four beads of wood glue, four new shaker pegs, a few smart raps with a rawhide mallet, and alles ist in ordnung.
[1] They are, however, very good for clearing out an existing partly-blocked hole, as their shape tends to make them operate in an edge-guided mode when so doing. Say, a 7/16" hole filled by the stump of a shaker peg that splintered when you tried to remove it because, unlike the other two², it was actually held in by more than a single tiny droplet of glue.
[2] This was originally a four-peg coat/robe rail. When I got it, one of the four pegs was missing, and I replaced the missing peg, glueing the replacement in securely. Now, a second peg has come out³ and gone missing, so I'm replacing all four to avoid having three slightly different styles among four pegs on the same rail.
[3] See "single tiny droplet of glue" above. One might also say "held in place mostly by good intentions."