I’ve found the table saw to be the most accurate way to make picture frames and other miter cuts. The trouble with using the table saw is that it takes eight individual cuts to complete one frame. To solve this problem, I made the table saw sled shown above. It reduces the number of passes needed to make one frame from eight to three.
As you can see in the drawing below, the sled consists of a 1/2" plywood base with front and back bridges made from two pieces of 3/4" plywood laminated together. Two triangular fences attached to the base hold the four workpieces at the correct angle for mitering one end of each blank. Short sections of T-track sit in stopped grooves cut in the top of the fences. These T-track sections house hold-down clamps used to secure the workpieces to the sled. To cut the parts to length, a pair of fence extensions are secured to the T-tracks on the fences. They provide support for the workpieces. A section of T-track is attached to one side of each extension, allowing a stop block to slide along its length. The stop block can be locked in place to set the final length of your frame piece.
To build the sled, start by cutting the base to size. After gluing up the bridge pieces, shape them at the band saw. Round the upper edges, and attach them to the base with glue and screws. The miter bars are then attached to the bottom of the base using screws. These are spaced to accommodate the miter slots on your saw. Now, place the sled on the table saw and cut into the bridges and base to create the kerf.
Use a combination square to lay out and cut the fences to size. You can then rout the stopped dadoes along the edges. After installing the T-tracks in the grooves, attach the fences to the base using glue and screws.
Now cut the fence extensions and the keys to size. The keys fit in the opening of the T-track on the fences. The fence extensions are held in place with a knob and flange bolt. Next, screw a section of T-track to the extension. The stop block construction is similar to the fence extensions with a hardboard key fit into a dado. A knob and flange bolt are used to hold it to the T-track.
To cut miters, start by placing four frame pieces on the sled so they just overlap the kerf line. Lock them down as shown in the main photo. Pass the sled over the blade to make the first cut on all four pieces. Now remove the frame pieces and install the two fence extensions. Orient the extensions as shown in the photo above and lock them down in the T-tracks.
Set one stop block for the length of a frame stile and the other for the length of a rail. Insert one stile and one rail piece on the sled, lock them down, and pass the sled over the blade to make the second cut. Now, install the other stile and rail and cut them to size.
