Start by laying out the centers of the 3 ½” holes leaving ½” at each end and ½” between each hole. This is made easy if you use a story stick
Mark a small tic mark on the edge of the board at the center line of each hole. Transfer the marks to the other side of the board with the Story Stick or a square. Just mark a small tic mark where the center of the hole lines up with the edge. Draw a line using a square in at one of the tic marks that is 2 ¼” long and mark the end.
Install the 3 ½” hole saw in the drill press. Set the pilot bit on the mark that is 2 ¼” in from the edge of the work piece and lock the bit down on the mark. Set a fence against the work piece and clamp it against the work piece. Draw a tic mark on the fence that lines up with the line on the work piece
Release the bit and start the drill press. Drill the six holes by aligning the tic marks with the mark on the fence. After all six holes are drilled install the 1 ¾” hole saw in the drill press. Draw a line on the work piece in lime with one of the tic marks that is 1 3/8” in and mark the end of the line. Re-set the fence by setting the pilot bit on the mark and moving the fence to the work piece. Aligning the mark on the fence with the tic mark on the work piece and clamp it down. Drill the six 1 3/8”
Use the table saw to rip the pieces. Set the rip fence on the table saw so the blade center is 2 ¼” from the fence. Rip the 3 ½” piece in the center of the holes and rip the piece again so that you have two pieces the same. Re-set the fence so that the center of the blade is 1 3/8” from the fence and repeat the cuts as above.
Cut off a piece of the left over from the previous step that is 9” long and notch both ends ¾” down X 3/8” deep. For this step you can use a number of methods. I use a dado blade on the radial arm saw however a table mounted router with a ¾” straight bit will work also. You can use a back saw or hand saw too. After the end is notched, rip the piece into 4, ¾” X 9” pieces. These pieces will become the “stringers”.
Rip the balance of the left over stock into 3/8” strips and cut two pieces 8 ½” and two pieces 7 ¾” long. These will become the risers.
Begin assembly by marking the two 3/8” X ¾” x 8 ½: risers two and one quarter inches from the end and the two 7 ½” risers 1 3/8” from the end. The marked end will become the top
Make end frames with one 8 ½ “riser and one 7 ¾” riser and two ¾ X ¾ X 9”stringers. Start by fastening a stringer and the two risers at the bottom and the other stringer at the marks on the top of the risers. Make the other end frame on the opposite side to create handed sides. Be sure to check that the frames are square before gluing and nailing.
Install the lower racks on the frames with the risers against the rack and sitting on the stringer. Install the 3 ½” semicircles at the end of the frames with the longer riser at each end
Install the upper rack on the upper stringers keeping the larger semi circles at the rear.
Sand and finish as desired .