Segmented turning, also known as polychromatic turning, is a form of woodturning on a lathe where the initial workpiece is composed of multiple parts glued together. The process involves gluing several pieces of wood to create patterns and visual effects in turned projects.
In traditional wood turning, the template is a single piece of wood. The size, grain orientation and colors of the wood, will frame how it can be turned into the target object, such as a bowl, platter, or vase. With segmented turning, the size and patterns are limited only by imagination, skill and patience.
While the vast majority of segmented turnings are vessels of one sort or another, strictly speaking, any turned object comprising multiple pieces of glued wood could be classified as a segmented turning. Examples include pens, bowls, vases, salt mills, pepper mills, and rolling pins. By cutting and re-assembling pieces after they are turned, unique forms can be created, crossing over to pure art.
Necessarily abilities
In addition to design skills, segmented turning demands precision woodworking skills as well as turning skills. Design and construction of a bowl blank—the wood piece mounted on the lathe for turning a vessel—requires angled miter joints cut to tolerances of as little as a tenth of one degree or better.
Techniques and varities
There are essentially two different techniques for constructing a bowl blank: ring construction and stave construction.
Ring construction is the most common. A ring-constructed blank comprises rings glued in a cylindrical stack. Though a platter or shallow bowl could be made from a single ring, stacking many rings is more typical. Apart from a lid or a base made and added after the fact, the height of the finished piece is a function of the number of rings and the height of each ring, which can vary for effect. Each ring comprises three or more pieces cut and glued to form a triangle, square, pentagon, hexagon, etc. The more pieces in a ring, the more challenging for the turner, because there are more opportunities for precision errors—gaps and misalignments in the joints between pieces. The individual pieces making up a ring themselves are often assembled from smaller pieces of contrasting or complementary colors to achieve striking patterns in the finished piece. This adds to the complexity and challenge for the turner.
Native American pottery, basket, and textile designs, particularly from the southwest U.S., frequently inspire form and design features. These patterns are often geometric in design and thus are easier to recreate than more fluid forms found in nature.
Stave constructions are assembled like barrels—cylinders constructed from multiple long, vertically oriented pieces. As a rule, the grain in a ring-constructed turning runs horizontally in the finished piece, while the grain in a stave-constructed turning runs vertically, from top to bottom.
Another category of segmented turning called Open Segmented Turning is similar to ring construction but small gaps are left between the segments. Successive rings are offset so the segments interlock with the ring above and below. This type of segmentation seems very delicate and is somewhat transparent but it is generally quite strong. This concept was introduced by Yosh Sugiyama in the early 1980s.
A segmented turning can combine ring construction, stave construction, and solid, non-segmented wood as well in a single piece. However, wood expands and contracts in the direction perpendicular to its grain as a function of its moisture content, itself a function of ambient humidity. In this case, during design and assembly, the turner has to be mindful of the impact on long term structural integrity of assembling the constituent pieces into incompatible, non-parallel grain directions.
Examples of bowls from boards
An important variation of the ring construction technique is known as "bowl from a board". Imagine a flat, square board bisected to create two identical rectangles, like two twin beds placed side-by-side to form a king-sized, square bed. Rings are created by cutting concentric semicircles from each of the two boards, one concentric half-ring a mirrored-shape of a half-ring from the other. The semicircles are typically cut with a bandsaw, but a scrollsaw, jigsaw, or coping saw would work. The blade of the saw used to cut the semicircles is set at an angle from the vertical, typically 45-60 degrees, such that when each mirrored pair is glued together to form a complete ring, the rings are shaped like cross sections of a cone. The rings are then stacked to create a cone-shaped blank. An incredible variety of visual effects can be achieved as a function of how the boards are constructed before the concentric rings are cut.
Historical impact and modern evolution
There are ongoing discussions as to whether turning is a trade, craft, or an art form. Turning in its original form was certainly utilitarian. The surname "Turner" may derive in many cases from those who worked in production wood turning. Many turners produce spindle work for furniture, architectural work, toys, and bowls. But in recent years, many artists use turned pieces as a canvas for carving, pyrography, gold leaf work, inlay, stain and painting.
Woodworking is the skill of making items from wood, and includes cabinet making, wood carving, joinery, carpentry, and woodturning.
Joinery is a part of woodworking that involves joining pieces of wood, engineered lumber, or synthetic substitutes, to produce more complex items. Some woodworking joints employ mechanical fasteners, bindings, or adhesives, while others use only wood elements.
A jigsaw puzzle is a tiling puzzle that requires the assembly of often oddly shaped interlocking and mosaiced pieces, each of which typically has a portion of a picture; when assembled, they produce a complete picture.
A lathe is a machine tool that rotates a workpiece about an axis of rotation to perform various operations such as cutting, sanding, knurling, drilling, deformation, facing, and turning, with tools that are applied to the workpiece to create an object with symmetry about that axis.
Millstones or mill stones are stones used in gristmills, for grinding wheat or other grains. They are sometimes referred to as grindstones or grinding stones.
Wood carving is a form of woodworking by means of a cutting tool (knife) in one hand or a chisel by two hands or with one hand on a chisel and one hand on a mallet, resulting in a wooden figure or figurine, or in the sculptural ornamentation of a wooden object. The phrase may also refer to the finished product, from individual sculptures to hand-worked mouldings composing part of a tracery.
Woodturning is the craft of using a wood lathe with hand-held tools to cut a shape that is symmetrical around the axis of rotation. Like the potter's wheel, the wood lathe is a simple mechanism that can generate a variety of forms. The operator is known as a turner, and the skills needed to use the tools were traditionally known as turnery. In pre-industrial England, these skills were sufficiently difficult to be known as 'the misterie' of the turners guild. The skills to use the tools by hand, without a fixed point of contact with the wood, distinguish woodturning and the wood lathe from the machinist's lathe, or metal-working lathe.
Intarsia is a form of wood inlaying that is similar to marquetry. The start of the practice dates from before the seventh century AD. The technique of intarsia inlays sections of wood within the solid wood matrix of floors and walls or of tabletops and other furniture; by contrast marquetry assembles a pattern out of veneers glued upon the carcass. The word intarsia may derive from the Latin word interserere.
Frame and panel construction, also called rail and stile, is a woodworking technique often used in the making of doors, wainscoting, and other decorative features for cabinets, furniture, and homes. The basic idea is to capture a 'floating' panel within a sturdy frame, as opposed to techniques used in making a slab solid wood cabinet door or drawer front, the door is constructed of several solid wood pieces running in a vertical or horizontal direction with exposed endgrains. Usually, the panel is not glued to the frame but is left to 'float' within it so that seasonal movement of the wood comprising the panel does not distort the frame.
Wood shingles are thin, tapered pieces of wood primarily used to cover roofs and walls of buildings to protect them from the weather. Historically shingles, also known as shakes, were split from straight grained, knot free bolts of wood. Today shingles are mostly made by being cut which distinguishes them from shakes, which are made by being split out of a bolt.
A Windsor chair is a chair built with a solid wooden seat into which the chair-back and legs are round-tenoned, or pushed into drilled holes, in contrast to standard chairs. The seats of Windsor chairs were often carved into a shallow dish or saddle shape for comfort. Traditionally, the legs and uprights were usually turned on a pole lathe. The back and sometimes the arm pieces are formed from steam bent pieces of wood.
Wood grain is the longitudinal arrangement of wood fibers or the pattern resulting from such an arrangement.
In woodworking, veneer refers to thin slices of wood and sometimes bark, usually thinner than 3 mm, that typically are glued onto core panels to produce flat panels such as doors, tops and panels for cabinets, parquet floors and parts of furniture. They are also used in marquetry. Plywood consists of three or more layers of veneer. Normally, each is glued with its grain at right angles to adjacent layers for strength. Veneer beading is a thin layer of decorative edging placed around objects, such as jewelry boxes. Veneer is also used to replace decorative papers in Wood Veneer HPL.
A butt joint is a technique in which two pieces of material are joined by simply placing their ends together without any special shaping. The name "butt joint" comes from the way the material is joined together. The butt joint is the simplest joint to make since it merely involves cutting the material to the appropriate length and butting them together. It is also the weakest because unless some form of reinforcement is used, it relies upon glue or welding alone to hold it together. Because the orientation of the material usually presents only one end to a long gluing or welding surface, the resulting joint is inherently weak.
Fly rod building is the art of constructing a fly fishing rod to match the performance desires of the individual angler. Fly rods are usually made of graphite or cane poles. There are several commercial manufacturers of fly rods, including Echo, Hardy, Zephrus, G. Loomis, Orvis, Reddington, Sage, Scott, St. Croix, Temple Fork Outfitters, and R. L. Winston; however, many individuals make fly rods for personal pleasure or profit.
This glossary of woodworking lists a number of specialized terms and concepts used in woodworking, carpentry, and related disciplines.
Bodging is a traditional woodturning craft, using green (unseasoned) wood to make chair legs and other cylindrical parts of chairs. The work was done close to where a tree was felled. The itinerant craftsman who made the chair legs was known as a bodger or chair-bodger.
The American Association of Woodturners (AAW) is the principal organization in the United States supporting the art and craft of woodturning. It is sometimes stylized as American Association of Wood Turners (AAW). Established in 1986 and headquartered in Saint Paul, Minnesota, the organization encompasses more than 15,000 members in the United States and many foreign nations. As of 2013, the AAW was affiliated with nearly 350 local chapters worldwide. In addition to sponsoring an annual national symposium, the AAW provides support to local clubs for outreach and education. The 25th anniversary of the AAW was celebrated in 2011 at the annual symposium held in Saint Paul. Phil McDonald is executive director of the organization.
Warm glass or kiln-formed glass is the working of glass, usually for artistic purposes, by heating it in a kiln. The processes used depend on the temperature reached and range from fusing and slumping to casting.
Michelle Holzapfel is an American woodturner and a participant in the American Craft movement. Michelle Holzapfel has five decades of experience turning and carving native hardwoods in Marlboro, Vermont, where she has lived her adult life. Holzapfel fits the definitions of both Studio artist and Material movement artist. A product of the revolutionary back-to-the-earth movement of 1960s and 1970s, she attributes the expressiveness of her turned and carved forms to the idealism of those years. Raised in rural Rhode Island, she has worked alone in her Vermont studio—shared only with her husband, the furniture maker and educator David Holzapfel—since 1976. Her wood pieces which feature intricate carvings have been exhibited in museums and galleries in the U.S., Australia and Europe. Publications featuring her work include but are not limited to House Beautiful, American Craft, Woodworking, and Fine Woodworking.
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