How to Make Wooden Bowls Using Your Bandsaw

Materials:
Wood Boards - I use red oak and maple in this example: 3/4" by 2-3/8" by 6' linear ft for the sides; and 3/4" by 4" by about 3' linear ft for the bottoms (resawed and planed to 3/8" or less thickness).
MDF Board - 11" by 22" for the jig
Wood Glue
Masking Tape
A Few Nails - 6d and 8d
Sandpaper - 100, 150, 220, and 320 grid
Danish Oil Finish or similar

Tools:
Bandsaw - 1/8" or 1/4" blade
Miter Saw
Drill
Clamps

Additional Useful Tools if Available:
Bench Top Belt Sander and/or Spindle Sander
Finish Sander
Router or Router Table
Planer

The bowl sides are made from several stacked 'ring' layers. The dimensions given are flexible, adjust to suit your needs. What I show will yield four to six bowls with the largest outside diameter of 6-3/4", and about 2-1/4 " tall.  Start with a 3/4" oak board, 2-3/8" wide. Two layers will require about 22" linear inches.

Resaw (slice) the board in half to get two boards at about 3/8" thick by 2-3/8" wide. While this isn't absolutely necessary, the bowls will look nicer if each layer is thinner than the 3/4" board. Run the board through a thickness planer if you have one, otherwise don't worry about it.

Set your miter saw to 22.5 degrees and cut 8 pieces at 2-3/4" outside (long) length; see picture. This will give you 8 segments for an octagonal 'ring'. You will need to cut a total of 48 segments for six layers. By assembling the layers from octagons, the end-grain of the wood will be hidden when you cut the bowl, and your bowl sides will look and finish a lot nicer.

Now glue up each layer (octagon). The easiest way to do this is by setting up a fence on your workbench, and setting the individual segments on masking tape, sticky side up as shown in the picture. Apply glue, then 'roll-up' the segments into an octagon. Lay flat (I use wax paper to prevent the glue from sticking to the bench), and close the octagon. The masking tape is your glueing-clamp. Try to get the butt-joints to close and fold the tape over to hold everything together. Don't worry about the glue squeeze-out, just wipe clean, and make sure you octagon is laying down flat. The butt joints don't have to be very strong. Try to avoid larger gaps in the joints, they will show in your final bowl.
Make six of these octagons. Let the glue dry for a few hours.

Once the glue has hardened, remove the tape and scrape off any excess glue; and sand the octagons to make sure they are flat. Don't worry about how the surfaces look; just make sure they are flat enough to make a good glue joint with the next layer.
If you have any larger gaps in the butt joints, fill in with wood putty or glue/sawdust mixture. Small gaps will not show much in the final bowl.
Stack and glue together the octagon layers you prepared in the prior step. When stacking, make sure to offset the butt joints from layer to layer to make a strong wall for the bowl. I rotate each octagon for a one-half overlap, but you could create more of a 'spiral' pattern by using less of a turn. Each octagon ring adds 3/8" to the height of the side of the bowl. Six layers make a nice 2-1/4" rim for a 5" to 7" diameter bowl. Make sure that your stack is reasonably straight and doesn't look like the "Leaning Tower of Pisa".
In the pictures, I definitely used too much glue; don't worry, the glue squeeze-out and glue drips will not show up in your bowls. Clamp the assembly and let dry overnight.

While you wait for the glue in your stack of octagons to dry, you can prepare the jig to cut the rings for the bowl walls.
Start with a 22" by 11" piece of 3/4" MDF. First, mount a stop on the underside of the board five inches from the trailing (short) edge. The stop will need to clear your bandsaw front fence rail and stop the jig-board at the front of the bandsaw table. I used several nails for the stop, cut very short in order to clear the front fence rail. You may use a wooden stop block, or whatever fits your bandsaw. The jig will slide on your bandsaw table along the fence and into the blade.

Once you have the stop installed on your jig board, set the bandsaw fence for 1-1/2" and run the jig (stop down) along the fence into the blade until you hit the stop. This will cut a straight line (kerf)  into your jig 1-1/2" from the left edge. Back out from the bandsaw. With a carpenter's square, draw a perpendicular line from the fence-edge of the board to the end of the cut and extend across the board. This line represents the front edge of your saw blade. It will also be the line on which you will locate the pivot points for cutting the circles for the bowl.
Drill a 3/32" hole on this line 3-1/2" from the kerf (i.e. 5" from fence-edge) and insert a 6d nail. This pivot point will produce a 3-1/2" radius, i.e.  7" diameter circle (Fence still at 1-1/2" as before!).

Cut, fit, and glue a small scrap piece of plywood like a 'spoke' in the bottom layer of your glued-up stack. Mark the circular center of the stack by drawing lines across along the butt joints. Drill a 3/32" hole through the marked center in the spoke. This is your pivot point for cutting the circle walls. See pictures for illustration.
Mount the stack on your jig with the 6d nail set in the pivot point and thru into the jig. Drill a 1/8" diameter hole offset from the pivot point through the spoke and partially into the jig. Don't drill all the way through! This hole will accept an 8d nail to stop the stack from rotating when you first cut into it. You'll see below how this works. Insert the 8d nail.
Set the bandsaw fence to 1-3/4". Now run the jig into the blade along the fence, with the stack mounted on the pivot hole and the 8d nail stop in place. This will cut a second kerf into your jig, and partially cut into your stack until you hit the stop. Once you hit the stop, shut off the bandsaw. Clamp the jig to the bandsaw table; then remove the 8d nail stop. Turn on the bandsaw and slowly turn the stack into the blade until you complete the circular cut. Turn off the bandsaw, unclamp and back out the jig. You just completed the first cut - the outside of your largest bowl. 
All following circular cuts will use the same procedure. See the video in the next step.
Use a 1/8" or 1/4" bandsaw blade for best results. A 1/8" blade is required to cut smaller circles.

Now move the fence 1/4" to the left. Clear off any sawdust from the jig and the bandsaw table. With the stack on the jig and the 8d nail stop in place, run the jig again along the fence into the blade. Once you hit the jig stop, turn off the bandsaw, clamp the jig to the bandsaw table, remove the 8d nail stop, and cut your next complete circle. Back out, move the fence, and repeat. See pictures and the video clip.

Repeat the circular cuts until you run out of  stack width. I get six good rings out of the sample shown. The two smaller inner circles are difficult for the 1/4" blade; an 1/8" blade is better for a clean cut.

Save the inside/outside waste pieces if you want to test different stains for your bowls later on.

I get six good rings for making six nesting bowls. Note that I purposefully cut the rings at different width of 1/4" to 3/8" in order to show variations. The width is obviously determined by how far you move the fence over between subsequent cuts. Your jig will have a number of parallel kerfs in it, representing each of the cuts you made. You can use the jig again for future projects.

Next you glue the seams in each ring to close them up. I use a piece of an index card or a narrow strip of wood to apply glue to the inside of the seam, and spring clamps to close the seam. Wipe off any glue squeeze-out with a wet rag; it's easier to clean now than after the glue dries.
Let dry overnight.

Sand the outside of each 'ring' wall on a benchtop belt sander. Let the ring run with the belt while you push down on the inside (wear leather work gloves!). See the video. Be careful and don't apply too much pressure. Get the outside smooth; but don't worry about finish-sanding the outside yet, it should be finished after the bowl has been completely assembled.

If you have a spindle sander, use it to sand the inside of each ring smooth. Finish the inside by hand with 150, 220, and 320 grid sandpaper. Do this before you attach the bottom; it will be much more difficult to get a smooth inside finish after the bowl has been assembled.

I use 1/4" thick red oak boards to make the bowl bottoms. You can make the boards by resawing 3/4" oak with your bandsaw and then running them through your planer, or you can buy them at a big box or hobby store. Lay out the boards to fit the bowl diameter and edge-glue together. I use masking tape on the bottom side to hold the boards together during the glue-up. It also helps with glue squeeze out. Let the glue set overnight before sanding.

Now sand both sides of the bottoms with 80 or 100 grid to flatten any seams. Then finish-sand only the inside bowl bottom with 150, 220, and 320 grid sand paper to prepare for staining before attaching to the bowl side. The bottom-bottom :) will be finished later.

Place the bowl on the bottom panel and draw a pencil line around the outside. Then apply a thin line of glue to the bottom of the bowl ring, and a small line of glue along the pencil line you drew around the outside. Try to avoid getting glue or glue squeeze-out on the bowl inside; it's a little difficult to clean. Press the bowl ring onto the bottom panel, and clamp in place. Clean up any visible glue with a wet rag. Let the glue dry for a few hours.

Trim the excess outside on your bandsaw by cutting as close as you can, but don't cut into or marr your bowl side, then use your router or router table to flush-trim the outside bottom with a trim bit.

Optionally, if you bowl rim is 1/4" or thicker, you can reinforce the bottom attachment with 1/8" dowels inserted from the bottom. This adds a nice touch but is not necessary. See pictures for details. 

Finally, sand the outside of your bowl through successive grids; I like 100, 150, 220, and optionally 320. Sand the bowl bottom-bottom to your desired finish.

Now you are ready to stain and finish your bowls.

Finish the bowls with your favorite stain or finish. I use Danish oil (natural, golden oak, or dark walnut); then I let it dry for two days. Don't apply a second coat to soon, it makes a 'gummy' and sticky mess. Apply as many coats as it takes to make a good looking finish.
Use a polyurethane stain or spray if you prefer.
If you want to use the bowls for serving or presenting food, apply a finish that is FDA approved for food.

Here are a few pictures of bowls I made during the past year from mesquite and other woods.

Variations:

(1) Use different colored woods in each layer, or in each segment of a layer for additional visual effects. I have also used smaller special pieces of wood I brought home from trips or from volunteer projects we've done with students. Great memories embedded into your bowl!

(2) If you set your bandsaw table at an angle when you cut the 'rings' you can make slanted sides for your bowl. 

(3) You could also use this method to make round boxes with lids, stacking toys for children, a 'Lazy Susan' serving tray, a round picture or mirror frame, etc. If you use a scroll saw instead of a bandsaw you could cut smaller diameter napkin rings.

Use your imagination!