I purchased a Joybird Z-chair for my first apartment about 5 years ago. A few weeks after we got Sunny he decided to use the ends of each arm as a chew toy in addition to making it his personal nighttime retreat.
I made an initial repair before I knew much about woodworking by sawing off the damage and then sanding down the nubs to round them a bit. It wasn’t pretty, but it was better.
When we moved to Houston we sanded down the entire frame of the chair and re-stained it a dark walnut color. Enter our other hound, Tig, a year later and I woke up to some freshly chewed arms. After ignoring the problem for several months I hatched a plan to repair the arms using some scrap walnut I had.
I started this project much like my previous repair attempt. I carefully measured the same distance from the interior crook and sawed straight down, revealing the biscuit joints that held the two parts of the arms together.
Making walnut blanks
I had some scrap 3/4 walnut from another project that I planned on doubling up to create a blank for the ends of the arms. The first step was to measure the angle the bottom part of the arm made with the sawed surface. This ended up being 31.6-degrees, which was a locking notch on my miter saw! (I’m sure that has significance in trim or something).
The reason to cut the blanks with this angle is to reduce the amount of material that will need to be removed to form the final shape.
I cut four pieces with the adjacent (remember your trigonometry here) side slightly longer than twice the semi-major axis of the sawed surface (which essentially made an oval). Assessing each piece for how it matched up with another, I glued two blanks making sure to mate their edges and clamping for a few hours.
Drilling for dowels
I knew that I could not just surface glue the blanks to the ends of the arms — not enough surface area for a strong joint — so I decided to try my luck drilling 3/8-inch holes in the blanks and then transferring the dowel location to the frame. This actually worked remarkably well.
The first step was to hold the blanks up to each arm and transfer the oval perimeter to the blank (and also making sure to mark which one was right and left!). Using this as a guide I marked a location roughly in the center of each outlined perimeter on the blanks. Then using a hand drill I drilled 3/8-inch holes as close to perpendicular to the surface of the blank as possible (a drill press would make this operation much less nerve-wracking) and at about an inch of depth.
I glued in some ~2-inch long 3/8-inch pine dowel and waited for the glue to set up.
I then transferred the dowel location from the blank to the end of each arm by carefully measuring the distance from the marked perimeter to the dowel circumference. Drilling a 1-inch deep hole set this up for final glue-up.
Glue-up, final shaping, and finishing
I applied glue on the mating surfaces as well as the hole drilled in the arm for the dowel. I then clamped the blanks for a couple of hours before moving on the shaping.
Shaping consisted of using a block plane to shave down the blanks. This works because I was transferring the surface contour of the existing arm on to the blanks and the planes were ending at a line (i.e. the point of the arm). I’m sure I could have sawn more off before using the plane, but it was nice to end up with a big pile of wood shavings at the end.
I sanded the arms down with 150- and then 400-grit sandpaper, which stripped some of the existing finish off the arms. Luckily, I still had the walnut stainI had used previously. After staining I applied three coats of polyurethane, sanding with 400-grit paper between applications.
The walnut blanks matched surprisingly well to the walnut finish. Obviously, the grain doesn’t match, but I think this repair is pretty cool and gives a good story behind an heirloom piece of furniture.