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Oak timber is a strong and hard wood with many uses, such as for furniture, floors, building frames, and veneers. [70] The wood of a red oak Quercus cerris (the Turkey oak) has better mechanical properties than those of the white oaks Q. petraea and Q. robur; the heartwood and sapwood have similar mechanical properties. [71]
When testing wood in lumber form, the Janka test is always carried out on wood from the tree trunk (known as the heartwood), and the standard sample (according to ASTM D143) is at 12% moisture content and clear of knots. [3] The hardness of wood varies with the direction of the wood grain. Testing on the surface of a plank, perpendicular to the ...
Cross-section of wood showing heart shakes. Shakes are cracks in timber. Arising in cut timber they generally cause a reduction in strength. When found in a log they can result in a significant amount of waste, when a log is converted to lumber.
In ring-porous woods the vessels of the early wood often appear on a finished surface as darker than the denser latewood, though on cross sections of heartwood the reverse is commonly true. Otherwise the color of wood is no indication of strength. Abnormal discoloration of wood often denotes a diseased condition, indicating unsoundness.
Live oak lumber is rarely used for furniture, because it warps and twists while drying. The wood of live oaks continues to be used occasionally in shipbuilding—and in tool handles for its strength, energy absorption, and density, although modern composites are often substituted with good effect.
Note that the ultimate strength of a beam in bending depends on the ultimate strength of its material and its section ... Oak wood (along grain) 11: 0.76 ±0.17 [21 ...
Fumed oak choir stalls at Clonfert Cathedral, Ireland. Ammonia fuming is a wood finishing process that darkens wood and brings out the grain pattern. It consists of exposing the wood to fumes from a strong aqueous solution of ammonium hydroxide which reacts with the tannins in the wood.
It is also known as the strength-to-weight ratio or strength/weight ratio or strength-to-mass ratio. In fiber or textile applications, tenacity is the usual measure of specific strength. The SI unit for specific strength is Pa ⋅ m 3 / kg , or N ⋅m/kg, which is dimensionally equivalent to m 2 /s 2 , though the latter form is rarely used.