Decorative Woodturning Artful Designs with Exotic Woods. by
Heiko Weiner
Part 2
The First Segmented Project: A Decorative Wooden Bowl. www.hwrwood.com
Summary of Part 1 Introduction to Segmented Woodturning. Armed with the contents of this Introduction you now should be able to understand the basic terminology of segmented wood turning. The resources provided in Part 1 will allow you to select your materials, perform the necessary calculations, and select the tools and equipment needed. Carefully review the safety recommendations for tools and equipment, and consider personal protection for respiratory safety and ventilation in your work area. Starting with Part 2 of this series, a selection of decorative woodturning projects ranging from simple to more complex designs will be introduced. The projects cover segmented woodturnings using wood only, and also mixed-materials designs that incorporate semi-precious stones and minerals, synthetic materials, and jewelry-grade metals. Each project description includes information on materials, step-by-step instruction with actual photographs, and is intended to demonstrate particular designs and techniques. Feel free to mix or replace materials, and apply the techniques to your own designs.
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Part 2 The First Segmented Project: A Small, Decorative Wooden Bowl.
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Method 2: Align the stock material with the miter fence, and carry out the first cut. Then, flip the board over, and remove just enough wood, to create the proper angle on one side of the segment. Then, flip the board back to the original side, align with the stop block, and carry out the next cut, which will produce the segment. After that, the board is flipped back again, and another cut, just removing enough material to create the proper angle is made. The short “segment� is then discarded. The board is then flipped back, again aligned with the stop block, and the next segment is cut. Continue with this sequence until the desired number of segments has
Note: This method uses more material (producing fewer segments from a single board), but results in preservation of the grain after assembly, i.e., all segments align with the same side. This may be desired for preserving the grain direction for heavily figured woods. 14
Segment Cutting In this section, all of the segments needed will be cut using the same setting on the table saw. We will cut all segments for the center ring (2 x 8 segments from each of board 1 and 2), and the 16 segments for the top ring. Note that the number of segments for each ring is identical (16), and also their length (due to the same diameter of both rings). As a result, the miter angle needed for all cuts is also the same with 11.25 degree. My preferred set-up is shown below. I added a 3/4” plywood board to the sliding table. The angle on the cutting side of the blade allows for the segments to drop away from the blade. Clamp, holding Stop Block
Sliding Table & Miter Fence, segment angle - (11.25 degree, set for n = 16)
Stop Block
Fence Cutting Stock (board) for segments ¾” board with zero clearance slot, and 45 degree edge (allow segments to move away from blade) Saw blade (10”/90 teeth, 1/8” wide)
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Turning Take the time to decide and turn the outside to the desired shape: The outer shape is the most important part for the final impression! Next, proceed with turning the upper (open) side of the bowl. Turn the opening to its intended width (approximately 3 1/8� / 80 mm). You can now invert the bowl, and re-clamp using the outer jaws of the chuck, follow with turning it to the desired shape. This will also allow you to finish the bottom of the bowl. Invert again, and now finish the inside. Try to achieve a smooth transition at the top of the bowl, on the inside, and towards the
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Finishing Before proceeding to finish your project, make sure you have completed all of the turning that was needed, and your piece does exhibit its final shape. One of the most important features of a turned project is the outer shape, much more so than any complicated or intricate design pattern. Your turning should be fairly smooth and even. Start sanding with 80 – 100 grid sandpaper or textile-backed abrasives, and work your way up to 150 – 220 grid. Make sure your sanding abrasives are clean, do not over-use them, and replace clogged or dull abrasive papers or textiles frequently. There are some different thoughts on how far to take sanding before applying the first coat of a finish. At any rate, make sure that all of the uneven marks and scratches have been removed before moving on to a higher (i.e., finer) grid. If your lathe allows to turn in reverse, sand in both directions. Check progress by running your hand back and forth across the surface. Wood fibers tend to bent and lay flat following the direction of the turning. You can remove these fibers by either sanding them off once the lathe is turned off or, more easily by reversing its direction. This will also help with sections of end grain that are more difficult to finish smoothly. Sanding with too fine of a grid sometimes tends to close pores on some woods, making it more difficult for the first layer of finish to penetrate the wood surface. I sand at least to a 220 grid, sometimes even up to 400 grid before applying the initial coat, which could be a sealer in some cases. 25