The Love of My Life suggested that for my next wood turning project I should try to assemble a set of stacked bowls in the Japanese style of bento stacked lunch boxes or jubako tiered lacquered boxes.
I had cut several square blocks of hemlock so those were good candidates for the stacking lunch boxes/bowls. I traced diagonal lines from the 4 corners on each block to find the exact center of the block.
With the drill press I used a 2 1/8 Forsner bit to drill a .25 inch deep hole in the center of each
block. I used a compass to draw a circle on the face with the drilled hole. Using the powered miter saw I cut off the 4 corners from each block and trimmed off any sides of the blocks that extended out beyond the radius of the drawn circle. This resulted changing the shape of the block face from
square to octagonal, and that makes the block much easier to turn into a cylinder. The holes in the face of the blocks are for mounting the block on the lathe with an expansion chuck. After turning the block into a cylinder I then cut a tenon on the tail stock end of the block for reverse mounting the block with a compression chuck.
For the two bowls that were to be stacked on top of the base bowl I also cut an indent into the rim of the base of those bowls and that indent would allow that bowl to sit inside the bowl below it. Once I had reversed the block into the compression chuck I hollowed out the insides of the bowls and sanded the inside and outside of the bowls. I then had to reverse chuck the bowls once more using a jam chuck to turn off the remaining tenon from the bottom of the bowls. For the most part, the jam chuck will only permit removing some of the tenon before the chuck begins to slip, so to remove the rest of the tenon I used a flexible handsaw. When I turned the block for the top bowl, which is smaller in height than the other bowls, I parted off that section of the block that was excess and left a tenon on it so I could mount the parted section and turn a lid for the stacked bowl set. That lid has an indent on the underside of the lid to allow the lid to sit securely inside the top bowl.
The top bowl presented a couple of other problems while I was turning it. First, a knot located in the corner of the bowl popped out while I was turning the inside corner of the bowl. This left a 3/8 to 1/2 inch hole in the bowl. Luckily the knot was intact, so I put some glue on it and reinserted it into the hole. After the glue dried I had to turn the bowl again to smooth out the knot edges in both the inside and outside of the bowl. As I smoothed out the outside of the bowl with a scraper, I noticed a 1/8 inch hole in the side of the bowl where the grain had torn out. The hole did not crack or degrade the rest of the side of the bowl, so I repaired that hole with a mixture of sawdust and glue.
The finished stack of bowls shows some nice grain patterns and even some interesting knots on the sides of the bowls and lid. I used an elastic strap and a small wedge of wood to hold the stack together.
Two things did not pan out as I had planned. The diameters of the 3 bowls varies from the
bottom to the top bowl in a pyramid fashion, while I had planned to make the bowls all the same diameter. To avoid that in the future, I think I will turn all the blocks into cylinders, one after the other, and insure that the final diameters are all the same after finishing and sanding. Also, the fit
between the indents in the bottom of the stacked bowls and the bowls below them is loose.
The same can be said for the lid in that its indent has a loose fit inside the third bowl. The solution maybe to limit the depth of the indent. However, if the wood moves, the indent had to be deep enough to keep the bowls and lid from binding. Next time I try this stacked bowl project I will use something other than hemlock to minimize the potential wood movement. So, let's consider this set of stacked lunch bowls as a prototype for a future project.