Woodworking Characteristics of Maple
Rock Maple - Acer saccharum
Other names: Hard Maple (Britain, Canada and USA); Sugar Maple (Canada); White Maple (sapwood) (USA)
Rock maple sometimes reaches a height of 130 ft and a diameter of 5 ft, but the usual height is 80 or 90 ft and diameters commonly 2 or 3 ft. Under forest conditions the length of clear bole may be such as 70ft, but when occurring singly in open country the first branches may only be 10 ft from the ground.
Rock maple grows in moist, rich, well drained soils either in pure stands or mixed with other species, both hardwoods and conifers. It is found in Newfoundland and westwards as far as Lake of woods on the Ontario-Manitoba boundary, and southwards to Oklahoma. Along the Appalachian and Alleghany mountains it occurs at altitudes of 3000 ft.
The Timber - General Description
A light colored wood of fine, even texture. The creamy white sapwood is not sharply defined from the heartwood which, however, generally has a more reddish tinge. Occasional large trees have a dark brown heart. Fine brown lines marking the growth rings are apparent on longitudinal surfaces and give rise to a distinctive figure on plain-sawn surfaces. The grain is usually straight, but wavy or curly grain sometimes occurs. The average weight is 45 lb/cu. Ft, seasoned.
The timber is stated to season at a slow rate but without undue difficulty
Kiln schedule E is suggested
Green to 12% moisture content:
About 5/16 in./ft or 2.5%
About 5/8 in./ft or 5.0%
Moisture content in 90% humidity
Moisture content in 60% humidity
Corresponding tangential movement
21/64 in./ft or 2.6%
Corresponding radial movement
7/32 in./ft or 1.8%
Rock maple is a dense, tough timber, possessing high strength properties for its weight. Thus, although when seasoned it is very little heavier than home grown beech, it is superior to that timber by about 20% in hardness, resistance to shock loads and resistance to splitting and about 15% stiffer. Its bending strength and compressive strength along the grain are about equal to those of beech.
Wood Bending Properties
No exact data is available on the minimum bending radius of this timber, but from the results of such tests as have been made, rock maple appears to be a very good bending wood. To ensure success, however, it requires stronger and more efficient bending apparatus than would be necessary for such well known bending timbers as beech or ash
Resistance to Insect Attack
Damage by Ambrosia (pinhole borer) beetles and by longhorn beetles is occasionally present. Seasoned timber is susceptible to attack by furniture beetles.
‘Pith flecks’ - caused by larvae of flies attacking the cambium of living trees -- are sometimes present in both sapwood and heartwood.
Natural Durability - Non Durable
Preservative Treatment - Resistant . The sapwood is permeable
This timber is fairly hard to work with hand or machine tools and has a moderately dulling effect on their cutting edges. It is comparable with sycamore but slightly harder in working. Straight grained material machines to a clean, smooth finish, but there is a tendency to ‘ride’ on cutters in planning and to tooth vibration in sawing, particularly with well seasoned timber.
Picking up occurs to a limited extent when curly grain is present and a cutting angle of 20 degree is best suited to the timber, it turns excellently and finishes cleanly in most other operations, though it tends to burn slightly in end-grain cutting e.g. cross-cutting and drilling. There is difficulty in driving nails and screws but it holds them firmly. The timber stains readily and gives excellent results with polish, paint and enamel. Saw type F is recommended. The timber can be glued satisfactorily.
Veneer and Plywood
Plain veneer is used for plywood manufacture in USA and Canada.
This species exhibits the valued ‘bird’s eye’ figure.
Rock maple is one of the most valuable commercial hardwoods of North America and is especially desirable where strength and resistance to wear are necessary. The timber is used for furniture, paneling, and cabinet work.
As a flooring timber it ranks high in resistance to abrasive action, wearing smoothly without surface disintegration, and is suitable for heavy industrial traffic in warehouses. It is sought after for roller skating rinks, dance halls, squash courts, etc.
Certain trees have a very fine figure called ‘bird’s eye’, and curly grain. They are usually cut to veneer, which makes very decorative plywood.
Rock maple turns well and is used in textile trade for rollers. Large quantities of timber are used for manufacture of shoe lasts.
The material is imported in the rough turned blocks of standard sizes. Where suitable ash cannot be obtained, maple is used for billiard cues.
The sap of this maple is the principal source of maple syrup and sugar.
Soft Maple - Acer saccharinum
Other names: Silver maple (Canada and USA)
Soft maple attains a height of 70-90 ft and a diameter of 2-4 ft. When grown in dense stands, the species produces straight, clear boles, but when grown in the open the trunk divides near the ground. It grows in rich, moist soils along border of streams and swamps. It never occurs in pure stands. Soft maple is found from southern Newfoundland, westwards through Quebec and Ontario and southwards throughout the eastern states.
The Timber - General Description
Soft maple is straight grained timber which bears a great resemblance to rock maple but is less hard and lighter in weight (about 33 lb./cu. Ft, on the average, when seasoned); the finished surface is not so lustrous and growth rings are comparatively indistinct. It may be distinguished by the rays, which are narrower and less conspicuous than in rock maple, and by frequent ‘pith flecks’
Kiln schedule E is suggested as likely to be suitable for this timber
Resistance to Insect Attack
It is probably susceptible to attack by furniture beetles. ‘Pith flecks’ are of more frequent occurrence in rock maple.
Natural Durability - Non durable
Preservative Treatment - Moderately Resistant. The sapwood is permeable
Soft maple is inferior to rock maple in all strength properties, being 40-50% softer, 20% less stiff, 20-30% weaker in bending, in compression along the grain and in resistance to radial splitting, 40% weaker in shear and in resistance to tangential splitting and has only about half the resistance to shock.
The species is less hard and works more easily than rock maple. Being straight grained in general, the wood machines to a good finish in most operations and no modifications to ordinary working conditions is required. There is a slight tendency to burn in cross-cutting and drilling when the clearance of cutting edges becomes reduced through dulling. The wood needs a little care in nailing but turns well and takes stain, polish and other finishing treatments excellently. Saw type E is recommended. The timber can be glued satisfactorily.
Veneer and Plywood
It is said to be suitable for plywood manufacture
The timber of soft maple resembles rock maple but is softer, and is used for same purposes where hardness and strength are not important factors. It is suitable for furniture and joinery work but not suitable for flooring. The timber turns well but is not considered suitable for shoe lasts.
Maple, Norway - Acer platanoides
It is found throughout Britain and on the continent from Scandinavia southwards into Asia Minor and the Caucasus. The tree grows up to 2ft in diameter and 70 ft high.
The properties of the timber are very similar to those of sycamore but it is not so hard. It is used for domestic woodware, brush backs and in the turnery trade.
Maple, Black - Acer nigrum
Other names: Hard or rock maple
Grows in south western Canada, in Quebec and southern Ontario, spreading south into the Lake States and the White Mountains. The wood has the same physical properties as A. saccharum and both species are commonly sold under the name of rock maple or hard maple
Maple, Japanese - Acer spp.
This timber is principally made up of A. palmatum and A. pictum var. typicum. It closely resembles rock maple, A. saccharum, although it is usually slightly darker in color and a little lighter in weight, averaging about 41 lb./cu ft. seasoned. In a lot of places this timber is used as a substitute for rock maple.
Maple, Pacific - Acer macrophyllum
Other names: Broad-leaved, big-leaf, Oregon and British Columbia maple (Canada and the United states)
It grows on the pacific coast of North America from northern British Columbia to California. The limited supply of suitable hardwood in this area makes the species of considerable local importance for flooring, furniture, cabinet work and interior joinery.
Maple, Field - Acer campestre
It grows throughout England and Wales, usually as a hedgerow tree seldom reaching commercial size. It is also found in Europe from southern Sweden to northern Greece and extends into the U.S.S.R and Asia Minor. The timber has properties very similar to sycamore
Maple, Red - Acer rubrum
Other names: Soft, scarlet, swamp and water maple
It grows from Newfoundland to the Lake of the Woods, Ontario and south into the Missisipi Valley and Tennessee. The wood is very similar to A. saccharinum and is commonly sold with that species as soft maple.
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