Segmented Turning
by Bill Kandler

 

Master turner Bill Kandler made a 2-hour video that follows the creation of a segmented turning from beginning to end. If you're interested in learning the technique, Bill sent us this quick run-through of his method - a summary of the video, if you will - to whet your appetite. The first 20 minutes or so focus on the design of a specific bowl project, using his own software, The Segmented Project Planner. By the end of this session, you'll have a full project plan that you can take to the shop and start cutting. The next task (28 minutes) is to build the feature ring.

 

"This is the most exciting part," says Bill. "The ring is actually two rings containing chevrons made of Purpleheart and Yellowheart. When put together, they look like lightning strikes (Photo 1). I use a lamination approach to build the chevrons (zigzags lying on their sides), so the bandsaw is used to cut a lot of strips of the two species. These are then dimensionally sanded to a constant 1/8" thickness with a drum sander. After gluing the sticks together to make the lamination board, I use a miter sled and my table saw (Photo 2) to cut a bunch of 3/8" slices. These are then glued together in pairs. Then I cut the pairs into segments while making sure the design is accurately centered in each segment."

Bill's next step (4 minutes) is to select maple for the rest of the bowl (Photo 3), and a little bit of ebony for some trim work. The maple and ebony are ripped to the appropriate widths and processed to the proper thicknesses. Maple/Ebony and Maple/Purpleheart sandwiches are then glued up as trim elements at the top, above and below the feature ring. He uses the table saw and miter sled (6 minutes of the video) to cut all the remaining segments.

 

Next up is ring gluing and ring flattening (Photo 4). Both of these sections are short because he's now in full blown assembly line operation, and it’s all repetitive stuff.

Finally, the real excitement begins with mounting the project on the lathe (7 minutes). The bottom layer is chucked up using a set of Cole jaws and a hole is cut for a plug, after which the outside is turned to a circle. After gluing in the plug, the bottom is turned round and a recess is cut for expansion chucking (Photo 5). Then the bottom is turned around again and he's ready to start building.

 

Stacking and turning the bowl takes the next 22 minutes. Bill glues one layer on at a time, followed by turning the outside true and then rough turning the inside, based on where the inner wall of the next layer will lie before he glues on the next layer. That next layer is held on center with a collection of parts attached to the tailstock during the gluing. Using this process means he doesn’t have to worry about accurate centering during the glueup, and he never has to reach very far beyond the tool rest during turning. He also sands the inside as he goes, so the inside of the bowl is finished when he reaches the top. Then, its down the outside in a race to the finish (Photo 6). Power and hand sanding down to 600-grit then prepares the piece for the final step. That would be applying the finish (13 minutes)...

"I use a home-built slow-speed attachment to the lathe which gives me a rotational speed of 30 rpm," says Bill. "That’s fast enough to prevent runs and sags and slow enough to keep material from flying off into space. The initial coats are with clear lacquer to preserve the colors as much as possible. After the surface is completely filled, a final coat of polyurethane (Photo 7) leaves the project with a tough and brilliantly shiny surface that will allow it to be used for years without signs of wear and tear."

  If you'd like to learn more about segmented turning, visit Bill at... http://www.segmentedturning.com.

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