Final product with a Tung oil and Renaissance wax polish.
Step 1: Who Said Geometry Was Useless?
It all begins with a little math. I wanted a lot of segments to equal 1/2" by 1/2" on the outer rim. The thickness of the boards were 1/2 in so the math will come into the number of segments and diameter of the bowl. The diameter of the bowl wasn't that critical other than it needed to be smaller than the capacity of my lathe. I planned on making 60 segments, however it ended up at 62 due to a slight error compounded 60 times in my miter gauge. Use lots of glue on both sides to keep the chance of the piece exploding to a minimum. The whole checkerboard pattern was made with a 4.5" X 30" X 1/2" piece of walnut and maple.
Step 2: Gluing Up the Segments.
Remember to use lots of glue! One thing I did discover was the thin end-grain interior portion absorbed the glue and swelled up quite a bit and caused the pattern to shift. Using a caul helped, but it's not perfect. 1/2 of the circle was glued up at a time.
Step 3: Preparing for the Ring Bevel Cuts
Using a forstner bit I created a reference surface to hot glue a pivot point which will be used later in cutting the rings out. I've also laid out the 45 degree cut lines which will be used in the next step to guide the cut alignment.
Step 4: Where the Magic Happens
The cut line is aligned with the blade and the pivot screw tightened for each ring. I couldn't resist a quick dry fit to get a sneak peek. At this point it was way better than I had imagined. This is the same technique as the "Bowl for a board" technique, however, instead of starting with a "board" it starts with a segmented "disk."
Step 5: 1/2 Rings Into Rings
Gluing up the rings is next on the list. They are no perfectly 90 degrees to each other so I have a 15" plywood disk with PSA sandpaper to take the bare minimum off to get them in perfect alignment.
Step 6: Starting to Build Out the Bowl
To stat building out the bowl I tru-up the enter hole in the 1st ring which will be glued onto a tenon on the base block of walnut. Before gluing on the next ring the face of the previous ring is flattened with chisels and a sanding board. The pattern is aligned and the next ring is glued on.
Step 7: Finishing the Rings and Rough Shaping.
It's just more of the same at this point. The rings are flattened on the sanding disk prior to glue-up. The inside and outside surfaces are trued up.
Step 8: Final Shaping, Sanding and Finishing
Don't forget your PPE! Everything is brought to final shape and size and brought down through the sanding grits to 400. The 1st coat is a Tung oil finish to bring out the contrasting wood colors. The final finish is a Renaissance wax polish. Once the polish is on the bottom is parted off and sanded flat.
I hope you all enjoyed. I can't tell you how much better this turned out than I was expecting. I've watched a ton of youtube videos on segmented turning and on "Bowl from a board" videos and I was struck by the idea to make this.
Step 9: Bonus Step
"Ohio Star" quilt block bowl using a similar technique.
Second Prize in the