When I make chairs with an old-school feel, it’s nice to leave the through-tenons on both the arms and seat a little proud. Lots of old chairs have proud tenons, which is likely a result of things shrinking and getting worn.
For years, I shaped my proud tenons with a shallow gouge (or a chisel) and a mallet. It worked, but if I struck the mallet too hard there were times that the grain would get torn up and the tenon would be ugly-ish.
Years ago I changed my technique to what is shown here. I think it’s easier and produces better results, but I’m not the best woodworker in Covington.
Step 1: Seal the Surrounding Surface
When I use proud tenons on a chair with a clear finish, I first seal the surrounding surface with two coats of shellac to prevent glue from fouling the arm or seat. It’s a quick process. I rag two thin coats of shellac on the unassembled arm or seat.
After the shellac is dry, I assemble the chair as usual, wedge the tenons and remove any excess glue with hot water and a toothbrush.
Step 2: Saw the Tenons
After the chair is assembled, I saw the tenons so they are all 3/16” (about 5mm) proud of the arm or seat. On the seat, I just eyeball it with a saw. On the arms, I take a scrap of crap 5mm plywood and drill a 3/4” hole through the center. Place the scrap over the wedged tenon and saw it flush to the scrap.
Step 3: Shape the Tenons
Now the fun part. I tape around the tenon. The tape prevents the surface from getting dented. Then I chip away at the tenon with my scorp. I press the scorp’s cutting edge against the tenon and lever the handles up, removing a chip. I work all around the tenon until it looks like I want it to.
Then I pull up the mass of tape with care and place it over the next tenon.
When all the tenons are shaped, I decide if I need to remove the shellac. If I am adding a film finish (such as shellac or lacquer) then I leave the shellac as-is. If I am finishing the chair with an oil/wax blend, I need to remove the shellac. This is easily done by flooding the surface with alcohol and wiping it up with a rag. I do this a couple of times, then lightly sand around the tenons.
— Christopher Schwarz