Segmented turning

From WikiWOOD

Segmented turning is a type of woodturning where small segments of wood are carefully glued together to form a blank from which a bowl, urn, or other type of vessel is turned.

There are numerous reasons why people make segmented turnings, including:

• making it possible to build up large blanks from relatively small amounts of wood
• reducing the amount of wood that is wasted
• making it possible to create ornate patterns that couldn't be made from solid pieces of wood

Description

Segmented turnings are usually made by gluing numerous carefully cut pieces of wood, called segments, together to form a ring, or layer. These layers are then glued together in stacks, to create the segmented blank. Often segments from contrasting woods are used to produce ornate patterns.

The shape of the segments is usually determined by dividing the number of segments for the layer into 360 (the number of degrees in a circle), then dividing the result in half to get the angle each side of the segment has to be cut at. For example: if there will be 10 segments on the layer, 360/10 = 36. 36/2 = 18 degrees. So each end of the 10 segments need to be cut at 18 degrees, to produce the 10 equal segments. A simpler method is to combine the two divisions, thus dividing 360 by 2 to produce 180, then simply dividing that by then the number of segments to get the angle to cut the ends of the segments (ie., 180/10=18).

The size of the segments depends on the diameter of the ring, and is harder to determine. For that, it is necessary to use a mathematical formula: Tan of the angle (determined above) times the diameter of the ring. Thus, for a 6" diameter ring with 10 segments, the formula would be: Tan(Radians(18)) * 6. Doing the math, Tan(Radians(18)) = 0.267949192. Multiplied times 6 equals 1.607695155. So each segment has to be cut at a length of 1.608" on the long side.

There are many templates and software programs available to help layout the design of these elaborate creations.

Open-segmented turning is a variation of segmented turning where small gaps are left between the segments.

External Links

Wikipedia has an article about Segmented turning

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