A couple years ago I bought a Kuri-Kuri Mini Drill from Highland Woodworking. It is a nice little tool (particularly because it uses standard hex-head bits), but I thought that as a “miniature bit brace” it needed some improvement. So I added a freely rotating grip and came up with

This was a little harder than it looks. The wooden grip started with a cut down spare file handle. I had to drill a 1/4″ hole straight through the center (I do not have a drill press). I then took a rip saw and cut it in two longitudinally, then put it back together around the shaft of the original drill. I did not trust glue to hold under the strains this will go through, so I screwed the two pieces together. Even with countersinking the edges of the screws stuck out too far, so I had to grind them down. After that some sanding smoothed it out. At first the grip did not turn smoothly—perhaps I should have used a 17/64″ bit (if I had one)—but some WD-40 fixed that. Then one heavy coat of boiled linseed oil as an initial finish. After that I can count on the natural oils from my hand.