Pilot hole bit, same size as screw's minor diameter
clamps (optional - only if using wood glue)
Cut the following pieces from your 1" x 6" : 6" x 8" (this will be the top piece that will be cut in half and have the hole drilled in it), 3" x 6" (front support piece), 6" x 36" (bottom), 3" x 36" (back)
Following the diagram in the photo, drill pilot holes and screw together your four pieces. If using glue, clamp and allow to dry.
Draw a line down the centre of the top piece, splitting it into two halves of 3" by 8". Drill a 3/8" diameter hole into this line, about 2" in from the back piece. This hole will enable the user to look through to align their cut line when preparing to saw their board.
With a handsaw, cut through this centre line and down through the front and back pieces until you graze the bottom board.
Make cut boxes to accommodate different widths of boards
Make a cut box to accommodate the cutting of a 45 degree angle. This could be used to cut boards to make different types of boxes, picture frames, etc.