I made this craftsman frame to fit a 16" x 24" chalkboard. I followed the plan, using 1x3's and 1x2's, attached with a Kreg Jig which made it easy. Oh, and glue. I usually buy full sheets of plywood and paint them with chalkboard paint but time was short and I used a 24" x 48" prepainted panel. I cut three 16" x 24" chalkboards from this panel.
I allowed 1/2" all around the inside dimension in order to glue and staple the chalkboard to the back of the frame. I decided to paint them all with a barn red paint sample. Cheap enough and they're going under the tree to three family members!