Projects & Related Things: Large Segmented Bowl

Because there are a lot of cuts that have to be precisely made I started out by running a check of the table saw blade to make sure it was cutting square to the table. First step is to cut a couple of scrap pieces that have parallel long edges then stand them on their cut edges like below. The green tape is my cutting reference mark set against the crosscut fence. Everything looks good on the left image but if you rotate the left board 180 degrees then the out of square becomes visible as shown on the right image.

Looking closer the below left image shows how much the blade is out-of-square. Some minor adjustment of the blade, in this case rotating the blade to the right brings the pieces together and all is square.

A trip into my wood storage gave me a good group of cherry and walnut pieces to start with.

In the last post I decided to float a center panel in the bottom bowl layer. The top image below shows a section through the bottom. For reference the center panel is just under 3/16" thick. To make the slot I made one pass on the table saw then moved the fence slightly to get the slot width I needed and made a second pass. The bottom photo shows that setup. The yellow and black thing is my magnetic fence. I set it up to apply a slight pressure to keep the board pressed against the rip fence on the right.

Once the slot is cut I can start on cutting the wedge-shaped pieces that will get glued together to make the bottom layer. Here is the jig with the slotted bottom blank in place. I will use the jig to cut 18 pieces for each of the 16 rings that will make up the bowl.

This is the first cut which gives me one side of the wedge and a triangular waste piece.

Before making the second cut I flip the piece 180 degrees so the slot that was facing me now is away from me. The piece is then slid to the right and clamped in place at the Outer Face Length I obtained from the spreadsheet.

A stop that has a matching angle is then clamped in place so I can make all 18 pieces the same size.

The cut is made and I have one piece the right size. For those of you with sharp eyes this first piece is not from the same place in the board as the previous photo. That’s because when I checked the piece’s size it was a couple hundredths of an inch small. I must have bumped the stop or something else. Anyway, I reset the stop, recut the first angled side and made the cut you see here to get the right sized piece number 1.

Now it’s on to the second piece. Because of the slot there is a specific inside and outside to the pieces. This means that I have to flip the board 180 degrees back to its original position, cut a new first taper in the top view below then in the bottom view flip the board 180 degrees, push it up to the stop and make the second cut to get the second completed piece. Two down and 16 to go for this ring.

In the image below, I have the first four pieces cut and arranged along with the waste triangular pieces. The other layers without a defined inside and outside will be cut without flipping thus eliminating the waste triangle resulting in less waste.

With all 18 pieces cut I made the floating circular panel and did a test fit.

To make the center disk float in the slot it could not be glued in-place and that presented a problem. Gluing up the rings is a really messy process and glue gets EVERYWHERE. There is no way I could glue the ring up and not get any in the slot which would glue the disk permanently in place losing its floating attribute. I thought about doing a two-step gluing process where I would only glue up half the ring at a time then insert the disk and very carefully glue the two halves together. Sounds good but if the slots are not aligned dead on then there would be no way to get the disk in place plus I would probably still have glue to clean out of the slot so the disk would fit. A couple of other ways all had their problems too. What I finally ended up doing was to finish the disk and the slots before the gluing all the pieces together. Here you can see the disk and ring sections prefinished with shellac where I do not want the glue to stick. Now when I do the actual turning I think that much of the finish will be removed but the slot to disk surfaces should not be permanently glued together. At least that’s the theory.

Gluing up this many pieces, getting them aligned and clamped can best be described as semi-controlled chaos or a mad race against time before the glue sets. According to the time stamp on the photos it took me right at four minutes from the time I started applying the glue until everything was together and the glue mess cleaned up. I have to say that a couple of dry runs beforehand did not hurt my time either.