- Species
- Juglans nigra
- Janka
- About 1,010 lbf
- Density
- About 610 kg/m³
- Stability
- High
- Relative cost
- Premium
- Target moisture
- 6 to 9 percent for heated interiors
Materials / Temperate hardwood
Black Walnut: Sapwood, Steaming, Grades and Specs
Dark, stable and easy to work. The usual choice for high end furniture, table tops and gift boxes, priced by width, length and sapwood allowed.
Black walnut is the dark North American hardwood. Its chocolate brown heartwood needs no stain, it machines and finishes well and it moves less than oak or maple, which is why it is used for high end furniture, dining and desk tops, cabinet fronts, boxes and small wood goods.
The trees grow scattered across the central and eastern United States, mostly on farmland and in mixed forests, so logs are smaller than oak and wide clear boards are scarce. That is why walnut is priced by width and length more steeply than other species, and why its grading rules allow more than other hardwoods.
Most cost and quality questions with walnut come back to sapwood. The narrow outer band of the tree is pale cream, and almost every board has some. How much sapwood you accept, and whether the lumber was steamed to darken it, sets both the look of the product and the price.
Properties
| Janka hardness | About 1,010 lbf (4,490 N) |
| Density at 12 percent moisture | About 610 kg/m³ |
| Shrinkage, green to oven dry | About 5.5 percent radial, 7.8 percent tangential |
| Grain and texture | Usually straight grain, sometimes wavy or curly. Medium texture with open pores that are finer than oak. |
| Color | Light to dark chocolate brown heartwood, sometimes with purple or gray tones. Pale cream sapwood. |
| Heartwood durability | Durable to very durable against decay. Mostly used indoors. |
| Steam bending | Good |
Typical published values for wood at about 12 percent moisture. Individual boards and panels vary.
Grades you will see on a quote
The grade decides how much clear wood you pay for. Name it on the RFQ and ask for photos of what the factory calls that grade.
- FAS and FAS 1 Face (NHLA)Walnut has special NHLA allowances: smaller minimum board width and length than standard FAS and sapwood is not counted as a defect. FAS walnut can still carry a lot of pale sapwood.
- No. 1 Common (NHLA)Shorter clear cuttings. The usual grade for furniture components and staves for edge-glued tops.
- No. 2A Common and rusticKnots, checks and color allowed. Used for rustic tops, small parts and boxes. Much lower price.
- Steamed walnutGreen lumber is steamed before drying so the sapwood darkens toward the heartwood color. The board is more uniform, the heartwood a little duller and grayer.
- Unsteamed or air dried walnutKeeps the richer, warmer heartwood color but shows pale sapwood clearly. Sold at a premium for natural finish products.
- Sap limitsBuyers add their own rule, for example sap free on one face or sapwood up to a stated percentage. Each limit lowers yield and raises price.
Where black walnut works
Products and parts where it earns its price, and where another material is the better buy.
Dining and desk tops
Edge-glued tops and slab style tops with a natural oil or lacquer finish.
High end furniture components
Legs, rails, frames and drawer fronts for collections where the wood color is the selling point.
Cabinet doors and fronts
Solid frames with walnut veneered panels to control cost and movement.
Gift boxes and small goods
Watch and jewelry boxes, trays, desk items and serving boards.
Turned and carved parts
Bowls, handles and knobs. Turns and carves cleanly.
Veneer faces
Sliced veneer on plywood or MDF for wide panels at a fraction of the cost of solid wood.
Where it is a poor fit
- Painted or heavily stained products. The price buys the natural color, so a paint grade species is the better choice.
- Large volumes of wide, long, sap free parts on a tight budget. Yield from walnut logs is low and the price rises steeply with each restriction.
- Products that must keep their exact color for years in sunlight. Walnut lightens and turns more golden under UV.
In the factory
How black walnut behaves in machining, gluing, finishing and drying. These points explain most price and quality differences between quotes.
- MachiningMachines, routes and turns cleanly with sharp tools. Softer than oak and maple, so cutter wear is moderate.
- GluingGlues well with PVAc and polyurethane adhesives. Glue lines show on light sapwood edges, so match color at each joint.
- FinishingTakes oil, lacquer and hard wax oil well. A pore filler gives a smooth gloss surface. A dye or toner can blend sapwood if your spec allows it.
- Health and safetyDust can irritate skin and airways. Factories should run dust extraction at sanding and routing stations.
At each process step
- 02Rough millingExpensive, so yield matters. Sapwood is pale and must be cut or allowed in writing. Color varies a lot from board to board.
- 05CNC routingRoutes and carves cleanly and is common for 5-axis shaped parts. Feed must stay steady to avoid burn on the dark surface.
- 08Veneering and pressingUsually plain sliced. Color varies a lot between flitches, so ask for sequenced leaves on matched sets.
- 11Inspection and packingSapwood and color variation must be sorted against the agreed grade before packing.
Hardness compared
Black walnut against the other solid woods buyers ask about. Hardness matters for tops, floors and parts that take knocks. For legs, frames and hidden parts, stability and price usually matter more.
- Hard maple1,450
- Beech1,450
- White oak1,360
- Ash1,320
- Red oak1,290
- Yellow birch1,260
- Acacia1,100
- Teak1,070
- Black walnut1,010
- Rubberwood980
- Cherry950
- Radiata pine710
- Poplar540
How to specify black walnut
Example RFQ lines you can adapt.
- Black walnut, NHLA No. 1 Common or better, steamed, sapwood up to 10 percent of each show face, kiln dried to 6 to 9 percent.
- Unsteamed black walnut for dining tops, sap free show face, staves at least 90 mm wide, color matched across each top.
- Black walnut rustic grade for serving boards, sound knots and small checks allowed if filled, no sapwood on the top face.
What to check on samples
Approve one sample in writing and keep it as the reference for every shipment.
- Sapwood on show faces measured against your stated limit
- Color spread between boards in one top and between batches: purple, gray and warm brown tones
- Whether sapwood was dyed or toned and whether that is allowed
- Filled knots and checks in rustic grades
- Moisture readings on finished parts
Alternatives to black walnut
When price, supply or the use case points elsewhere.
- CherryLower price than walnut for a warm, darker look. It starts light and darkens to reddish brown over months.
- White oak with dark stainA lower cost route to a dark brown finish, with a stronger grain pattern.
- AcaciaA lower cost plantation species with strong brown tones and lively color variation.
- Walnut veneered plywoodFor wide panels and backs, a walnut face over plywood or MDF cuts cost and movement.
Products often made in black walnut: table tops and countertops, turned parts and legs, cabinet doors and fronts, panels and veneer, millwork and mouldings, CNC routed parts, kitchenware and small wood goods, wood packaging and boxes.
Product lines in black walnut: dovetail drawer boxes, desk tops, furniture legs, stair parts, wood slat wall panels, cutting boards.
Questions about black walnut
Related guides:
- NHLA Hardwood Grades Explained: FAS, Select and Common for Buyers
- Custom Wood Table Tops: Specifications That Get an Accurate Quote
- Wooden Gift Boxes for Brands: Specs, Branding and Minimum Orders
Is steamed or unsteamed walnut better?
Neither is better, they suit different products. Steamed walnut is more even because the sapwood darkens. Unsteamed walnut has richer heartwood color but shows pale sapwood. For a natural finish with strict color rules, unsteamed with a sap limit is common.
How much sapwood is normal in walnut?
Almost every walnut board has some, and NHLA grading does not count sapwood as a defect. Put your own limit in the RFQ, for example sap free on one face or a maximum percentage of the face.
Why is walnut so much more expensive than oak?
Walnut trees are scattered and smaller, so wide, long, clear boards are scarce. Price climbs with width, length and every sapwood rule. Allowing narrower staves or some sapwood lowers cost.
Does walnut change color over time?
Yes. Walnut tends to lighten and turn warmer and more golden with light exposure, the opposite of cherry, which darkens. A UV resistant finish slows the change.
Other temperate hardwoods
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