Wood species
Hickory wood
Hickory is a hardwood; this page covers the true hickory group, led by shagbark hickory (Carya ovata). At 12% moisture content it has a Janka hardness of 1,880 lbf (8,363 N) and it weighs about 50 lb/ft³ (806 kg/m³), 4.2 lb (1.9 kg) per board foot.
Names and species on this page: shagbark hickory, mockernut, pignut, shellbark hickory, true hickory.
Key numbers
- Janka hardness, 12% MC
- 1,880 lbf (8,363 N)
- Green: 1,460 lbf (6,494 N)
- Weight at 12% MC
- 50 lb/ft³ (806 kg/m³)
- 4.2 lb per board foot
- Specific gravity (oven-dry weight)
- 0.72 at 12% MC volume
- 0.64 on green volume
- Shrinkage, green to oven-dry
- 10.5% tangential
- Radial 7.0%, volumetric 16.7%
One source: USDA Forest Products Laboratory, the authority for species properties it measured
Why: Measured by the USDA Forest Products Laboratory; hickory's density is worked from its specific gravity with the Handbook's own equation.
How much hickory moves
A 12 in wide flatsawn board of shagbark hickory that goes from 6% to 12% moisture content swells about 0.3 in (about 9/32 in, 7.5 mm). Quartersawn, the same board moves about 0.19 in (about 3/16 in, 4.7 mm). Flatsawn faces move 1.5 times as much as quartersawn ones, because the wood shrinks 10.5% around the growth rings but only 7.0% across them.
Worked with the Wood Handbook's dimensional change coefficients for shagbark hickory (the Handbook gives one row, "Hickory, true", for the group) (Table 13-5: 0.00411 tangential, 0.00259 radial per 1% change in moisture content), which hold between 6% and 14%. Individual boards vary: the Handbook gives shrinkage a coefficient of variation of about 15% (p. 4-11).
Color, grain and working
- Color
- Wide white sapwood and reddish heartwood.
- Working and character
- Exceptionally tough, heavy, hard and strong, and it shrinks considerably while drying.
- Uses
- Tool handles that must take shock, ladder rungs, athletic goods, dowels and furniture; lower grades for pallets; chips and sawdust for smoking meat.
Adapted in our own words from the Wood Handbook, Chapter 2, p. 2-7.
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE). Clear, straight-grained samples of shagbark hickory tested by the Forest Products Laboratory (Wood Handbook Table 5-3b). Knots and cross grain make lumber weaker than these clear samples (Handbook Chapter 5).
| Property | Green | 12% MC |
|---|---|---|
| Bending strength (MOR) | 11,000 psi (76 MPa) | 20,200 psi (139 MPa) |
| Stiffness (MOE) | 1,570,000 psi (10.8 GPa) | 2,160,000 psi (14.9 GPa) |
| Crushing strength (compression parallel to grain) | 4,580 psi (32 MPa) | 9,210 psi (64 MPa) |
| Compression perpendicular to grain | 840 psi (6 MPa) | 1,760 psi (12 MPa) |
| Shear parallel to grain | 1,520 psi (10 MPa) | 2,430 psi (17 MPa) |
| Tension perpendicular to grain | — | — |
A dash means the Handbook prints no value; none is filled in.
The true hickory group
The Handbook tests each species separately; they are sold together as hickory. Across the 4 species measured, Janka hardness at 12% runs from 1,810 to 2,140 lbf.
| Species | Janka, 12% MC | Weight, 12% MC | Tangential shrinkage |
|---|---|---|---|
| Shagbark hickoryCarya ovata | 1,880 lbf | 50 lb/ft³ | 10.5% |
| Mockernut hickoryCarya tomentosa | 1,970 lbf | 50 lb/ft³ | 11.0% |
| Pignut hickoryCarya glabra | 2,140 lbf | 52 lb/ft³ | 11.5% |
| Shellbark hickoryCarya laciniosa | 1,810 lbf | 48 lb/ft³ | 12.6% |
Dust and health
- Wood dust is classed as carcinogenic to humans (Group 1) by the International Agency for Research on Cancer, chiefly for cancers of the nose and sinuses.
- NIOSH recommends keeping wood dust exposure to 1 mg/m³ of total dust, as quoted in OSHA's sawmill guidance.
This is what the named authorities publish, not medical advice.
Compare with
Why these numbers
Why these numbers?
The situation
The USDA Forest Products Laboratory measured shagbark hickory at 1,880 lbf of side hardness at 12% moisture content, on clear, straight-grained samples (Wood Handbook Table 5-3b).
One source: USDA Forest Products Laboratory, the authority for species properties it measured , sources [1]
What that means
Side hardness (Janka) is the load needed to press a 0.444 in (11.28 mm) steel ball halfway into the wood across the grain; a higher number dents less (Handbook p. 5-5).
One source: USDA Forest Products Laboratory, the authority for species properties it measured , sources [1]
So
Density at 12% is water's density × specific gravity × (1 + 0.12) (Handbook Eq. 4-14): 62.43 × 0.72 × 1.12.
Arithmetic: exact by definition , sources [1]
The number
About 50 lb/ft³, or 4.2 lb per board foot (1/12 ft³), at 12% moisture content.
Arithmetic: exact by definition
Sources