This plan assumes you have a table saw. There are no dimensions given because you can make the box whatever size you want. We want to make the frame all from one board. So make sure it is at least twelve inches longer than the total length of all four sides. Make all these cuts before you cut your miters and keep the inside face of the stock down.
Cut a forty five degree bevel about one quarter of an inch wide a long the front edge of the board. Cut a groove for the glass Using a standard kerf blade make a cut one quarter of an inch deep and one half of an inch in from the same edge of the board with the bevel. Make the cut with the bevel down. This groove should accommodate a standard piece of glass. Cut a rabbit on the back edge of the stock for the back. With the saw blade the same height, move the fence over so it is a quarter of an inch from the blade. Stand the work piece on edge with the bevel facing the fence and make the cut. Raise the blade up to three eights of an inch. Move the fence over until it is an eighth of an inch from the blade. Position the work piece so the bevel is facing down and away from the fence and make the cut. You should now have a rabbit a quarter of an inch deep and three eighths of an inch wide. This will accommodate the plywood for the back. Now you can cut your miters and assemble. A few tips for assembly. Dry fit the four sides with the glass in place and check the fit of the glass and the miters. You can cut a thin piece of card board the size you need the glass to be. When you have the right fit with card board take it with you when you get the glass cut. Make sure the glass is in place before you glue all the corners together. Just using yellow glue like Tight Bond 2 will be enough to hold the frame together. A frame clamp can be helpful with assembly. Put your finish on all the parts before assembly. Just do not get finish on the miter cuts where the glue will go. Cut a quarter of an inch thick plywood to fit the back. After you mount the item to the back, (the piece of plywood), attach the back with tiny screws in case you ever want to take out the item without destroying the box. By Darrel Vickers