Maple

Also called: rock maple, hard maple, soft maple, sugar maple, acer

Maple is a hardwood cut from trees of the genus Acer. It ranges from a plain, tightly grained timber used for ordinary carpentry and turnery to one of the most sought-after decorative timbers in the trade, prized for wavy or speckled patterns that show up on its surface once it is cut and finished.

Hard maple, soft maple and the maple family

Not all maple is the same wood. Audels (1923) described hard maple plainly as "heavy, hard, strong, tough, and close-grained," meaning its fibres are packed tightly and evenly, which gives it a smooth, fine texture when worked. A closely related timber sold as white maple was described in similar terms: fine grained, hard, strong and heavy. Other maples are markedly less dense. Hoadley (1980) grouped soft maple with woods such as ash, cherry, oak, pecan and walnut as moderately dense timbers that glue well under good working conditions, setting it apart from the denser hard maple. The naming has caused confusion over the years. Holtzapffel (1846) considered maple closely allied to the sycamore, a tree sometimes itself called the great maple (Acer pseudoplatanus), and recorded that the common maple (Acer campestre) was much used in America for house carpentry and furniture, while in England the same tree gave a pale yellow brown wood put to lighter work only, in small turned wares such as boxes and butter prints.

Figure: birdseye, curl and fiddleback

Most maple grows with straight grain, meaning its fibres run parallel to the length of the board, but certain figured forms are deliberately sought out. The USDA (2021) notes that sugar maple usually grows straight grained, yet birdseye (a scatter of small swirling eyes across the surface), curly and fiddleback grain, both wavy patterns that catch the light in shifting bands, are often selected for furniture and small decorative items. That curl shows strongest when the board is cut on the radial face, meaning the saw follows a line out from the centre of the log so the growth rings run roughly edge to edge across the board rather than flat across its face. The name fiddleback comes from long use for the backs of violins, although Porter (2004) points out that violin backs were traditionally cut not from maple proper but from European sycamore. Under a hand lens, maple's rays, the narrow ribbons of tissue that run outward across the grain, are roughly the same width as its largest pores, a detail useful for telling the wood apart from similar timbers.

Working, gluing and use

Hard maple is used mainly for solid lumber and for veneer, the thin sheets peeled or sliced from a log for facing other material. It cuts cleanly enough by hand or by machine, though Porter (2004) rates its effect on cutting edges as a moderate one, so blades need resharpening more often than with softer timbers. Sugar maple in particular has become the benchmark timber against which glued joints in other woods are judged: Hoadley (1980) used it as the standard species for testing bond quality, assessing a glued joint by the stress it can bear and by how much of any failure runs through the wood itself rather than through the glue line. Some makers build up wide tops from many narrow strips of maple glued edge to edge rather than from a single wide board, a laminated construction noted by Landis (1987) as one maker's practice. Sugar maple's average specific gravity, a measure of how dense the wood is relative to water, is given by the USDA (2021) as 0.56.