By far the best peg shapers that I’ve used are those by Alberti Designs. They make a set of 12 blocks to cover all sizes of violin and cello peg. These shapers feature a series of sizes in smallish increments, the blades are tool steel planer knives and are very straight and sharp and hold their edges for a long time. Alberti claim that they will never need sharpening and if they do they will sell you an inexpensive replacement. They also manufacture the “skiver”, a dual purpose tool shown here. This extra item is worth every penny, it allows new pegs to be precisely fit into existing holes (rather than opening peg holes up to accommodate the new peg), thereby preserving original wood.
The first step in shaping pegs is to use the skiver to make a shallow saw cut around the base of the peg collar. The cut helps to prevent blowing off the collar (again!) when trimming the peg with the peg shaver. I use this prior to starting on each new hole.
To turn the pegs in the shaper I use this socket in a hand power drill. I think that Howard core sells a plastic version of the socket, I made this one after a visit to Robertsons Violins. At first I was skeptical about working this way thinking that everything would move too fast to control, but I soon found that, with the drill set to its lowest speed, I actually had more control over the work. Turning the peg at a constant rate allows the job to feed in more evenly and with less pressure than when turning the pegs by hand, you can take off a finer shaving and the finish on the peg is better. There’s also a time and no-blister bonus.
When you get onto your final hole on the peg shaper, use the skiver a couple of times to remove the step on the peg shank near the collar (next picture). Minimizing this step on the shank will prevent the tear out that normally occurs when too much material is fed into the shaper.
The skiver’s blade is dull except at the last 12mm. Insert your peg and feed it into the the blade to remove the step on the shank.
Having trimmed the new pegs to size the peg holes are opened to size using reamers. It is nice to start with a very small reamer such as the lute-peg reamer on the left, allowing time to adjust the pegs alignment. The spiral-cut reamer is supposed to prevent some of the chatter that occurs as the reamer cuts up into end grain. I’ve found that this reamer, which is very sharp, actually digs in more than the straight-cut reamer. The spiral-cut does however have a very good overall taper so I use it for the last 2mm or so.
When the peg is close to length use a finer file, and then take it down through the grades of sandpaper ending with an oil and pumice cloth.