Things You'll Need
Instructions
Cut two 18-inch long pieces from your 1 by 4-inch lumber.
Set one of the pieces on its longest narrow edge so the long, wide side is facing you.
Place the second piece on top of the first so the long, narrow edge is facing you and the back of the wood&'s underside is lined up with the first piece of wood. If you looked at it from the side, it would form an upside-down "L" shape.
Screw the pieces together by driving the screws down from the top. Use the leftover scrap from the lumber to help prop up the front edge while you complete the project.
Cut an 18-inch long piece of your dowel and glue it to the top of the front edge of your shelf with wood glue. This will keep the shot glasses from sliding off due to vibration.
Measure the distance from the inside of the dowel piece to the back of the shelf (it will be slightly less than 2 1/2 inches) and cut two more dowel pieces that length. Glue them onto the shelf to complete the safety ridge around the sides. The wall will, of course, keep the glasses from sliding off the back.
Attach the shelf to the wall after the glue dries by driving screws through the bottom support (the first piece of lumber you cut) into the wall.