I had been wanting to learn how to do Mortise and tenon joinery for a while now, but for one reason or another just hadn’t found the time. When my wife said she wanted a custom picture frame for a Disney puzzle she was building that she wanted to put in our daughters room I jumped at the chance. I came up with a simple but unique idea for a black walnut picture frame that was built using mortise and tenon joints instead of more traditional miter joints.
I used 4/4 black walnut for the frame. The frame is custom fit to the size of the puzzle with has an inside dimension of approx 21×27 inches.
Before I started the joinery I had to fix a flaw in the form of a hollow knot in one of my pieces of walnut. Since I didn’t want to waste good wood, and since it didn’t pass all the way through the board and had a very pleasant looking face I decided to fix it. I used painters tape to mask off the area around the knot and then filled it with epoxy and left it to dry. I then used card scrapers to smooth it out. I then marked the face side of the frame using green painters tape so I wouldn’t get it confused with the backside.
To create the mortise I marketed out the locations and used my drill press to remove the bulk of the material. I then used chisels and a mallet to clean up the tenon.
For the tenon I used my table saw. I cut the tenon to almost correct size. I left them slightly oversized. I then custom fit each tenon to its matching mortise using a shoulder plane and chisels to sneak up on the perfect fit.
After fitting each joint I test fit the entire frame together, and to my partial surprise it actually fit together! And I could pick the frame without any glue and it felt solid! Nice! The next step was to glue the frame together.
I then routed 2 grooves (Rabbets?) into the back of the frame using a rabbeting bit. The first groove was 1/8 deep and was the max width of my bit. This groove is intended to help me recess the hardware so the frame can sit flush to the wall. The second grove was using my largest bearing on the bit (smallest rabbet) and was 3/8 below the first grove or ½ in total depth from the back face of the frame. This is where the picture will go. I will be using a 1/8 piece of acrylic for the front, the puzzle is 1/8 thick and then a 1/8 piece of hardboard for the backing. I squared the corners of my Rabbets using a chisel and a mallet.
For the ends of the four sides I decided to leave them extend past the corner and stand proud, with a simple rounded end. To create the rounded ends I created a template out of ¼ hardboard. I then traced the round over’s onto the ends. I then cut the bulk of the waste of with a carcass saw. After I had removed the bulk of the waste I used a router and a pattern bit to finish the round over’s.
For the hanging hardware I simply placed the hardware on the backside of the frame at the desired locations and traced them on with Pencil (inside and outside) I then used a small hand router to recess the entire bracket so it would be flush with the backside of the frame and so that the center would be further recessed to allow for the head of the screws that will eventually secure the picture frame to the wall.
I then sanded everything smooth and finished the frame with boiled linseed oil and amber shellac.
I think it turned out nicely! it even sits flush to the wall.