Wood species
Ramin wood
Ramin is a hardwood (Gonystylus bancanus). At 12% moisture content it has a Janka hardness of 1,300 lbf (5,783 N) and it weighs about 40 lb/ft³ (633 kg/m³), 3.3 lb (1.49 kg) per board foot.
Key numbers
- Janka hardness, 12% MC
- 1,300 lbf (5,783 N)
- Green: 640 lbf (2,847 N)
- Weight at 12% MC
- 40 lb/ft³ (633 kg/m³)
- 3.3 lb per board foot
- Specific gravity (oven-dry weight)
- 0.52 on green volume
- Shrinkage, green to oven-dry
- 8.7% tangential
- Radial 4.3%, volumetric 13.4%
One source: USDA Forest Products Laboratory, collected from the world literature (its Tables 5-5 and 4-4)
Why: From the USDA Wood Handbook, which collected these values from the world literature; ramin's density is worked from its specific gravity with the Handbook's own equations.
How much ramin moves
A 12 in wide flatsawn board of ramin that goes from 6% to 12% moisture content swells about 0.22 in (about 7/32 in, 5.7 mm). Quartersawn, the same board moves about 0.11 in (about 3/32 in, 2.7 mm). Flatsawn faces move 2 times as much as quartersawn ones, because the wood shrinks 8.7% around the growth rings but only 4.3% across them.
Worked from the Wood Handbook's shrinkage values (Table 4-4) with its Eq. 13-4; the Handbook gives no movement coefficients for imported woods. Individual boards vary: the Handbook gives shrinkage a coefficient of variation of about 15% (p. 4-11).
Color, grain and working
- Color
- Pale straw, yellow or whitish throughout.
- Grain and texture
- Straight or shallowly interlocked; even, moderately fine texture like American mahogany, with no figure or luster.
- Working and character
- Moderately hard and heavy, easy to work, finishes and glues well. Not resistant to decay.
- Uses
- Moldings, dowels, broom handles, plywood, furniture, turnery and flooring.
The Handbook reports that the IUCN rates ramin critically endangered and that it is listed in CITES Appendix II.
Adapted in our own words from the Wood Handbook, Chapter 2, p. 2-34.
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE). Values for ramin from Wood Handbook Table 5-5b (p. 5-24), which the Handbook says were collected from the world literature, on clear, straight-grained specimens. Knots and cross grain make lumber weaker than these clear samples (Handbook Chapter 5).
| Property | Green | 12% MC |
|---|---|---|
| Bending strength (MOR) | 9,800 psi (68 MPa) | 18,500 psi (128 MPa) |
| Stiffness (MOE) | 1,570,000 psi (10.8 GPa) | 2,170,000 psi (15 GPa) |
| Crushing strength (compression parallel to grain) | 5,390 psi (37 MPa) | 10,080 psi (69 MPa) |
| Shear parallel to grain | 990 psi (7 MPa) | 1,520 psi (10 MPa) |
A dash means the Handbook prints no value; none is filled in.
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 Wood Handbook prints 1,300 lbf of side hardness at 12% moisture content for ramin, a value it says was collected from the world literature (Table 5-5b, p. 5-24).
One source: USDA Forest Products Laboratory, collected from the world literature (its Tables 5-5 and 4-4) , 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, collected from the world literature (its Tables 5-5 and 4-4) , sources [1]
So
The Handbook gives only the green specific gravity (0.52) for ramin, so it is moved to 12% with the volumetric shrinkage of 13.4% (Eqs. 4-9 and 4-11), then multiplied by water's density and 1.12 (Eq. 4-14).
Arithmetic: exact by definition , sources [1]
The number
About 40 lb/ft³, or 3.3 lb per board foot (1/12 ft³), at 12% moisture content.
Arithmetic: exact by definition
Sources