Decorative Woodturning Artful Designs with Exotic Woods. by
Heiko Weiner
Part 2
The First Segmented Project: A Decorative Wooden Bowl. www.hwrwood.com
No part of this manual may be reproduced for commercial purposes without prior obtaining a written permission of the author. The patterns and instructions in this manual are intended for the personal use of the reader, and may be reproduced for that purpose only.
HWR
®
© 2018 Heiko Weiner / HWRWood. All Rights Reserved.
Using hand tools, and operating machinery carry a serious risk of injury. The content described here is for informative purpose only. The reader releases and discharges the author, associates, owners and affiliates, their successors and assigns, of and from any and all claims or demands for injury to his/her person or property, resulting directly, or indirectly by reason of participation in the activities described, and hereby assumes full responsibility for his safety, and for all risk of injury to persons or property by reason thereof. Contact Information: Heiko Weiner • 4827 Baywood Dr., TX 77505 www.hwrwood.com • Phone (989) 859-0052
It is recommended to review the content of the introductory Part 1 “Introduction to Segmented Woodturning” before beginning with one of the segmented projects. A summary of the content that is provided in Part 1 is included below.
Part 1 “Introduction to Segmented Woodturning” Table of Contents (Part 1) Page No.
Basics of Segmented Woodturning
4
Domestic & Exotic Hardwoods
9
Common Hardwoods & Properties
13
Synthetic Materials
32
Adhesives & Glues
40
Finishing
43
Tools & Accessories
48
Shop Safety
51
Summary
55
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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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Review: Terms & Calculations The basic principle of designing segmented bowls is to construct individual rings, also referred to as Layers, then stacking the rings of varying diameter and thickness in order to achieve a desired layout, and then finish by turning it on a lathe. While extensive turning experience is not required to get started, it is a good idea to familiarize yourself with some basic turning techniques. After all, some significant work and time will go into assembling the three-dimensional layout of a segmented bowl, and you would want to be confident in finishing it successfully. Some similar, basic steps are part of many segmented turning projects, regardless of the size or its complexity. The projects descriptions in this project series will outline these basic sequences, and introduce certain techniques that can be used or modified for more advanced designs later on. I do recommend starting small, and getting familiar with some of the terminologies, calculations, and techniques. Review some of the basic terms and formulas as shown in Scheme 1.
Scheme 1. Several values are used to determine the materials needed for a segmented ring: Number of Segments (n); Segment Length (L); Segment Angle (MA). You will also need the Segment Height, and it’s Width. 6
Segment Length (L) = {Diameter (d) x 3.1416} / No. of Segments (n) = {Circumference (CF)} / No. of Segments (n) Miter Angle (MA) = 360 degree / (n) / 2 Number of Segments (n). The number of segments for a desired ring largely depends on its design. For average size turnings with diameters of 6 – 12 inches, this can be a number as low as 8 and all the way up to 80. Good average values are between 16 and 24, if the ring is made from the same size segments. It is a good idea to pick a number than can be divided by 4, such as 12, 16, 20, 24 and so on, which will allow to construct quarter rings that can be assembled into halves and subsequently, whole rings. I will explain the reason for this later in more detail. Segment Length (L). The length for a single segment is calculated by dividing the circumference (diameter x 3.14) by the number of segments (n). This value is also needed for calculating the amount of material (i.e., the total length of a board) that is needed to obtain a certain number of segments of this length. Segment Angle (MA). The angles for all segments (each segment has two) has to total 360 degree, regardless of their individual length. For a given number of segments, the segment angles (miter angles, MA) are obtained by dividing 360 by the number of segments (n) and dividing again by two (since two miter angles are needed for each segment). Segment Height. The height of a segment is determined by the vertical dimension of the ring. This value is also needed for estimating the amount of material that will be needed for a certain number of segments. 7
As a rough guideline, the length of a board for cutting a specific number of the same segments can be calculated as follows: Total Length = (L + 1/8”) * (n) * 1.10 with: L = Segment Length (”); 1/8” for blade width; (n) = number of segments needed; * 1.10 for a 10 % excess
This formula takes into account that you have decided on the height and the width of the segments that will be required. The formula includes a 10% excess for some additional segments if needed, and also some board length to securely hold on to while cutting the segments. I recommend using this calculation until you are comfortable that you can cut the segments safely, and do not need much excess material. When deciding on the number of segments (n) for a given ring, the diameter will mostly determine how many segments are reasonable. As a good first estimate, keep the number of segments between 12 and 24 for ring diameters of 6” to 12”. This will be sufficient for a large range of sizes.
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Segment Number & Miter Angle # of Segments (n)
Miter Angle (MA)/degree
4
45.000
8
22.500
10
18.000
12
15.000
14
12.857
16
11.250
20
9.000
24
7.500
28
6.428
32
5.625
36
5.000
Miter Angle (MA) = 360 degree / (n) / 2
Miter Angle (MA), 2x
Note that even if you try to cut the segments as precisely as possible that there will be small deviation that can lead to problems while assembling the ring. As an example, if the deviation in the miter angle is only off by 1/10 of a degree, the compounding error for a ring with 24 segments would total up to 4.8 degree, enough for the ring not to close. For this reason, I do recommend using segment numbers that can be divided into quarters, such as 12, 16, 20, 24 and so on. Small deviations can easily be corrected for quarter, and half (two quarter) rings. We will use this approach for the first project, and select a number of 16 segments for all rings to be assembled.
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Calculations & Blueprints Center Line 2 1
2 - Second Layer (Top Ring) 1 - First Layer (Center Pattern)
B
B - Bottom (Block)
Bottom (Block): Single Block, Diameter = 4.5”; Height = 0.5” First Layer: diameter = 5”; n = 16; L = 0.981”; Width = 1”; Height = 1.125”; MA = 11.25 degree Second Layer: diameter = 5”; n = 16; L = 0.981”; Width = 1”; Height = 0.5”; MA = 11.25 degree Although it may appear more intricate at first, only three layers (”rings”) are needed for this simple design. The Bottom layer is made from a single piece of material, and no individual segments will be needed. Later on, and when using more complex or larger designs, a segmented bottom layer may be warranted. The First Layer (Center Pattern) is actually made of three individual layers. However, they will be pre-glued (laminated) before cutting them into segments. The Second Layer (Top Ring) consists of a simple ring of the same material. 10
Table 1. Summary Table for Materials & Segment Dimensions. Miter # of Ring Ring Wood Board 1 Angle2 Segm. Width Height Length No. Diam. Type3 Length4 B 1
2
4.5 (114.3) 5.0 (127.0) 5.0 (127.0) 5.0 (127.0)
n.a.
n.a.
11.25
8
11.25
8
11.25
16
n.a.
0.5 (12.7)
n.a.
1.0 (25.4) 1.0 (25.4)
1.12 (28.6) 1.12 (28.6)
0.98 (24.9) 0.98 (24.9)
1.0 (25.4)
0.5 (12.7)
0.98 (24.9)
D D/L/D L/D/L D
4.5 (114.3) 9.73 (247.1) 9.73 (247.1) 9.73 (247.1)
1 Values in inches (mm) 2 Miter Angle (degree) = 360/n/2 3 Wood Type (D = dark; L = light) 4 Board, Total Length = (L + 1/8”) x (n) x 1.10; with L = Segment length; 1/8” for blade width; n = number of segments needed; x 1.10 for 10 % excess
A summary for materials and segment dimensions is provided in Table 1. After selecting a dark, and a light colored wood (i.e., Black Walnut, and Hard Maple) proceed with cutting the boards using the dimensions provided. To assure that all boards have the exact thickness before laminating, cut all boards with the same dimensions at one setting with your table saw: (1) Dark Wood (2x): 1” wide x 0.5” high x 10” length (2) Light Wood (2x): 1” wide x 0.5” high x 10” length
Cut together, same settings
(3) Dark Wood (1x): 1” wide x 0.125” high x 10” length (4) Light Wood (1x): 1” wide x 0.125” high x 10” length
Cut together, same settings
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Board Preparation & Sizing Pattern Sequence (Single Repeat Unit)
Board #1
Board #2
+ 8x
8x Σ (n) = 16
To finish preparation of Board #1, and Board #2, laminate (glue) each by combining the 3 pieces (2 x 0.5” in height + 1 x 0.125” in height): 0.5” (1.27 cm)
Board #1
0.125” (0.32 cm)
Board #1
0.5” (1.27 cm) 10” (25.4 cm)
Board #2
0.5” (1.27 cm) 0.125” (0.32 cm) 0.5” (1.27 cm)
Clamp (use Tidebond II; 3 clamps; both ends + center), and let sit for at least 2 hrs. 12
Segment Preparations There are two basic methods for cutting segments. Each one can be used for a straight (90 degree) cut, or for an angeled cut using a tilted blade on the table saw. Both methods use stock material (i.e., properly sized boards):
Method 1 (most common): Align the stock material with the miter fence (top side up), and carry out the first cut. With the first cut, remove just enough material from the end of the board to obtain a clean angled cut. The initial “segment� is then discarded. Then, flip the board over, properly align with a stop block, and proceed with the second cut. Continue until the desired number of segments has been cut.
Note: This method is most efficient, as nearly all of the stock material can be used. Using this method, however, results in segments with alternating sides. It is therefore best used for straight wood with an uniform grain. 13
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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Sanding (Disk Sander) Using a sharp, carbide-tip, wider blade with 80+ teeth can minimize the need for sanding. However, some segment ends will always need sanding in order to achieve a perfect glue joint. Check each segment for clean joint fit by�dry-fitting�, and sand if in doubt. Any open joints will show at the end, and even more so with lighter colored woods. The bottom line is that some sanding will always be required, regardless of how precisely the segments are cut. Small projects can be done by free-hand sanding, but for bigger ones, a sanding jig is recommended to achieve evenly round circles.
Facing outwards (away from the disk center)
Facing outwards (away from the disk center)
When sanding free-hand, do the following: (1) Have one of the long sides (outsides) of the segment contacting the disk first; (2) Sand lightly with little pressure; (3) Turn the segment over, and sand the (second) outside of the seg ment. Note: This will even out small errors in the vertical, 90 degree alignment of your sanding disk. 16
Center Ring Assembly There are no set rules of which ring or layer to start with, the order very much depends on your design. For smaller projects I recommend to (1) start with the center ring, (2) prepare the base next, and then (3) continue with the top layer(s). For each ring to be assembled, carry out the following (6) Steps. Note that this sequence is applicable to a large variety of projects, regardless of ring size or the number of segments. Recall that I recommended to select segment numbers that can be divided into quarters. The purpose of this will be shown in the following illustrations. (1) Start with gluing pairs (for a ring with 16 segments – 8 pairs); (2) Combine the pairs to obtain quarter rings (4 quarter rings, 4 seg ments ea.); (3) Check for accuracy of the 90 degree quarter circle, and correct by sanding if needed.
(1)
(2)
(3)
When assembling the segments, take note to use the alternating segment patterns. Check for the proper alignment of the center strip. 17
(4) Continue gluing & assembly by combining two of the quarter circles ea. to two half circles; (5) Check each half circle for accuracy of the 180 degree, and correct by sanding if needed; (6) Combine the two halfs, insert into a hose clamp, and tighten.
(4)
(5) Since the quarter rings had been corrected for 90 degrees (step 3), assembly of two quarters to one half ring is accomplished with only minor deviation. Correcting the half ring for 180 degrees before combining both halves assures that the ring will close.
(6)
Using this general sequence will allow to obtain clean joints and even circles for rings of nearly any size. 18
Bowl Bottom The preparation of the bowl bottom consists in the (4) following steps: (1) Mark (trace) a circle on the 4.5” x 4.5” x 0.5” blank using the center ring as template. You can do this while the hose clamp is still attached to the ring; (2) Next, cut a circle from the (4.5” x 4.5” x 0.5”) blank (band saw). Center Ring
(1) Bottom Blank
(2)
Bowl Bottom
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(3) Turn one side, and add a circular recess to this side. Use NOVA Cole flat jaws to mount the bowl bottom securely. The bottom does not have to be turned perfectly at this time. We will finish the bottom later on. When turning the recess, carefully consider the maximum width the jaws will open (step 4) in order to still be able to clamp the bottom securely. For a regular size NOVA chuck, this should be around 2.36� (60 mm); (4) Remove the bottom from the flat jaws, reverse, and mount it securely using the recess. Next turn the outside true and even for gluing. Adding some curvature to the bottom is recommended - but not necessary at this time.
(4)
Recess (~ 60 mm x 3 mm/ 2 3/8� x 1/8�)
Curvature
(3)
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Bowl Assembly, Part 1 Begin assembly of the bowl by gluing (stacking) the base onto the center ring. Prepare the center ring for gluing by sanding one side flat and even (use a belt/disk sander). You can also use NOVA Cole flat jaws for this, and is definitely recommended for larger rings. Check via “dry-fit� to ensure that the seam will be tight and closed all around. Then add glue to the center ring, and place the bowl bottom as centered as possible onto the ring. After ~5 mins, when the bottom does no longer slides easily, add pressure by clamping, or just adding some weight; only medium pressure is needed. Set aside for at least 45 mins before continuing with additional assembly. You can leave the chuck attached (see below). If you need to remove it, mark the bottom of the bowl, so you can clamp it later again using the same position. Weights
Chuck Center Ring
Bottom
In the mean time, continue with assembling the Top Ring. 21
Top Ring Assembly The top ring consists of 16 segments of the same material. For assembly of the ring (second, segmented layer), follow the same steps (1) – (6) as outlined earlier for the Center Ring Assembly:
(1) Assemble segments to pairs (8x).
(2) Combine pairs to quarters (4 x).
(3) Check quarters for 90 degree fit.
(4) Combine quarters to halves (2)
(5) Check halves for 180 degree fit.
(6) Combine the halves and clamp securely. 22
Bowl Assembly, Part 2 Continue assembly of the bowl by gluing (stacking) the top ring onto the center ring. Return the chuck with the center ring and bottom to the lathe. Proceed with turning off the segment edges, and turn the ring flat and true. Finish the surface with sanding. Prepare the top ring for gluing by sanding one side flat and even (belt/disk sander). “Dry-fit� the top ring to ensure that the seam will be tight and closed all around. Add glue, and place the top ring as centered as possible onto the center ring. Center Ring
Chuck Bottom Center Ring Set aside (overnight) before turning the bowl.
Weights
Top Ring
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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
Try to sand evenly, and with medium pressure. I also recommend sanding at an intermediate speed in order to avoid overheating of the wood and the abrasives. Finer grid abrasives in particular tend to just slip over the surface, rather than cutting if the speed is too high.
Figure 1. The use of a sanding sealer is optional, and depends largely on the type of wood, and the intended use of your project.
Using a sanding sealer, or grain-filler as the first coat is optional, and may be useful with some coarse, open-grained woods such as pine, cedar, poplar, walnut, or mahogany. Its intentions is to fill pores, and allow sanding to a more smooth and shiny surface. It will also reduce the amounts of finish that have to be applied in order to fill the grain, and provide adequate protection towards heavy use or the elements. I have used products like Mylands Cellulose Sanding Sealer (lacquer-based) and Zinsser SealCoat (shellac-based) with good results. For the more natural, open-grained appearance of decorative wood turnings, however, a sealer is not required, and may even be undesired. 26
Use a food-safe sealer and finish if your project is intended to be used in contact with foods. Do not use any products that are based on oils found in some nuts, such as walnut, peanuts and the like since these can cause allergic reactions for people with sensitivities to contents in nuts and seeds. There are numerous options for food-safe finishes. Be diligent and educate yourself, and select the ones you feel comfortable with. I personally prefer to use the line of Tried & True finishes for all indoor projects intended for use with foods, children’s toys, furniture etc. All Tried & True products are 100% solvent free, zero VOC, and safe for food and skin contact. These natural finishes combine beeswax with pine resin or polymerized linseed oil to bring out the beauty of wood, they are highly durable, and decorative finishes. I usually apply 3-4 coats from start to finish. Read the instructions carefully, note that sufficient curing time needs to be maintained between coats.
Figure 2. Tried & True products are natural, 100% solvent free, zero VOC, and safe for food and skin contact.
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The last step in finishing your project may be the application of a polishing paste (wax-based), applied with a clean cloth, and buffed to high shine at medium to high speed. I often use small amounts of Tried & True finish (bees wax and linseed oil), and polish the surface with a cheese cloth or clean staining pad. Repeat the final polishing step once more, if desired. In order to maintain color and appearance, avoid display or storage in areas with excessive heat or humidity. Prevent exposure to direct sunlight as the UV radiation will break down colors and stains over time, and will darken the appearance of most woods.
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Literature & Further Reading Various books and magazine articles are available on the subject of Segmented Woodturning and the related techniques. I recommend to review the Series Introduction “Introduction to Segmented Woodturning” for additional details on materials, calculations, techniques, and shop safety. Below are some references I used for composing this series of projects. Additional references are included for further reading: [1] Nish, D. L.; “Woodturning with Ray Allen”, Fox Chapel Publishing, 2004. [2] Tibbetts, M.; “The Art of Segmented Woodturning”, Linden Publishing, 2006. [3] Nish, D. L.; “Artistic Woodturning”, Brigham Young University Press, 1980. [4] Rannefeld, C.; “Laminated Designs in Wood”, Lark Books, 1998. [5] Smith, W.; “Segmented Turning”, Schiffer Publishing Ltd., 2002. [6] Hiebert, J.; Hazeu, H.; Bergen, T.; Bergen, H.; “Fabulous Turned-Wood Projects”, Sterling Publishing Co., New York, 2005. [7] Raffan, R.; “Turning Wood”, The Taunton Press, 2001. [8] Ellsworth, D.; “Ellsworth on Woodturning”, Fox Chapel Publishing, 2008. Notes
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