Woods to Know: African Walnut | Canadian Woodworking & Home Improvement

Woods to Know: African Walnut

African Walnut (Lovoa trichiloides)

by Peter MacSween

Endemic to tropical West Africa, African Walnut is a large tree growing to heights of 150 feet.  African Walnut logs typically have long branch-free trunks with diameters up to 4 feet.  These trees will provide lots of lumber in decent lengths and widths.  The grain is usually interlocked which will produce a shimmering ribbon stripe on quartersawn material.
 
The heartwood colours range from a golden yellow to reddish brown, often overlayed with dark black streaks.  Upon exposure to light and air, the colour will darken to a deeper brown.  The sapwood is a yellow to light gray and is sharply demarcated from the heartwood.  Occasionally, there is a narrow colour transition zone present between the sapwood and the heartwood.
 
African Walnut is considered a diffuse pored wood with the large pores scattered evenly within the growth ring.  This gives the wood a medium and consistent texture.  Indistinct growth rings and a high natural luster are characteristic.  It dries fairly well, although shake may be present in some trees.  While it is a fairly durable wood, it is usually used in interior applications
 
Despite its name, African Walnut is not a true Walnut.  The true Walnuts belong to the genus Juglans while African walnut is actually a member of the family Meliaceae which contains the genuine Mahoganies, Sapele and Spanish Cedar.

WTK_african-walnut
 
African Walnut is similar to Black Walnut in strength and hardness.  Both woods tend to turn brown as they age, this may be the reason the tree was named African Walnut.  However, it is probably more of a marketing consideration, given that the name Walnut has a certain prestige associated with it.
 
Straight grained African Walnut is cooperative when worked by hand or machine.  However, the presence of interlocked grain in the wood increases tear out when working by hand or machining.  Sharp, carbide tooling and reduced cutting angles and feed rates are recommended.  This contrasts with Black Walnut where interlocked grain is rare and machining is much less problematic.  African Walnut glues, stains and finishes well.  Nails and screws should be predrilled. 
 
African Walnut is an ideal choice for furniture, cabinetry and turned objects.  Solid African Walnut is most commonly seen in North America as flooring.  Specialty wood dealers may import it as solid lumber.  It is also easily sourced as a veneer in North America.
 
African Walnut is not on the CITES list.  However, since its population has seen a consistent decline over the past three generations it is on the IUCN Red List.  Pricing is moderate for an imported species.  Expect to pay more for figured solids or figured veneer. 

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end-grain
 
Some woodworkers have experienced skin and respiratory irritation when working with African Walnut although severe reactions are uncommon.  Its good practise to wear dust masks and practise standard safety procedures when working with a new species until you understand your own personal tolerances.
 
Woodworkers have the luxury of an extensive supply chain.  Demand for genuine Black Walnut is high and the price is high as well, so many woodworkers will consider less expensive substitutes.  I like to think that African Walnut should be appreciated on its own merits.  Working with any new species will allow woodworkers to expand their skill set as they meet the challenges of working with a new wood.
 

Average Dried Weight34 lbs/ft³A measure of its weight at 12% moisture and an ambient temperature of 70°F.
Specific Gravity..54A measure of the ratio of its density compared to water (at 12% MC)
ShrinkageRadial: 3.7
Tangential: 5.9
Volumetric: 10.8
Radial (the amount of crosswise shrinkage);
Tangential (the amount of lengthwise shrinkage);
Volumetric (the total amount of shrinkage.)
T/R Ratio1.6A measure of the uniformity of tangential to radial shrinkage.
Janka Hardness940 lbs.A measure of resistance to denting and abrasion.
Crushing Strength6,700 lbf/in2A measure of compression strength parallel to the grain.
Colour
Heartwood is a golden yellow to reddish brown, sometimes with darker streaks and veins. Color tends to darken upon exposure and with age. Sapwood is a medium yellow to light gray,and is generally narrow: it can be up to 3 inches (7.5 cm) wide, and is clearly demarcated from heartwood; a narrow transition zone is sometimes present between heartwood and sapwood. African Walnut also displays a ribbon-stripe figuring on quartersawn surfaces, similar to Sapele.
GrainUsually slightly interlocked, but is sometimes straight.
TextureMedium, uniform texture, with a high level of natural luster.
Workability
Generally easy to work with both hand and machine tools, though care must be taken to avoid tearout when surfacing interlocked grain. Turns, glues, and finishes well.
Uses
Veneer, plywood, flooring, furniture, cabinetry, and turned objects.
PriceContact your local dealer
For a list of Canadian retailers click here

 
 
wooddatabase
 
Photos and Specifications Courtesy of: The Wood Database