Ebony

 

Botanical Background:

The ebony family, Ebenaceae, contains slightly upwards of 300 species, organized into 5 genera, mostly of tropical distribution and especially plentiful in Southeast Asia and the East Indies. The genus Diospyros, with about 250 species, dominates the family and is by far the most dispersed, in that it is found in both the Eastern and Western Hemispheres. Also, a few of its species (mostly persimmons) range north into warm temperate climates, both in North America and in the Orient.

Variability Among the Ebonies:

The traditional ebony of 18th and 19th century commerce was Diospyros ebenum, native to southern India and Ceylon (Sri Lanka.) It’s jet black heartwood, fine texture, comfortably low shrinkage values, uniform texture and rather high density (average specific gravity in the range of 0.80, depending upon growing conditions) made it a very dependable species for precision turnings and it has long been a favorite “accent” species in musical instrument making. Due to its increasing scarcity, most commercial “black” ebony is now coming from African species which are, unfortunately, also becoming scarce, expensive, and limited to stock of small dimensions and short lengths. In fact, it is often sold by the pound rather than by board foot.

Most other ebony species display variegated pigmentation, such as the beautiful amber brown and black veining found in Macassar ebony, from the Celebes, and marblewood from the Andaman Islands…but these are only a couple of the better known marbled ebonies and there are many more. For example, our own native persimmon, which often displays black veining on a predominantly cinnamon brown base color is a truly beautiful wood. Because the sapwood of virtually all of the ebonies tends to be light cream colored or sometimes start white, these woods all lend themselves to some very striking, high contrast turnings, if special attention is given to incorporating both heartwood and sapwood in the piece.

Some Drawbacks:

Although the darkly pigmented heartwood of most of the ebonies has very good decay resistance, the sapwood tends to bluestain (spalt) easily…which isn’t necessarily bad news for turners seeking figure that really commands attention…but it does limit the use of the wood to “heartwood only” when planning exterior applications or using it in other humid environments, such as kitchens or bathrooms. Another negative of some of the ebonies is that they experience rather high shrinkage. Both the Indian and African black ebonies are respectably stable, but the persimmons tend to be highly unstable, difficult to season and prone to checking. In fact, our native persimmon’s average volumetric shrinkage, green to ovendry, is a whopping 19.1%...and that’s one of the highest of all of our commercially important native hardwoods. Another serious concern to keep in mind is that the fine powdery dust produced when shaping and sanding ebony is very irritating. Intensive and/or prolonged exposure to this dust can lead to health problems and even allergic sensitivity for some individuals. The ebonies are great turning woods, but treat them with caution.

 

Information developed by Jon Arno or Mark Kauder and posted by Mark  on www.woodcentral.com . Mark has graciously given East Texas Woodturners permission to add the write ups to our site.  Thanks Jon and Mark.