While one or two men in a small community may furnish all the wood and metal work needed by it, in large towns and cities the great amount and variety of work required necessitate a division of labor, resulting in numerous trades or crafts. Some of these are exclusively wood-working, others metal - working, while a few combine portions of both.

To follow or employ any one of the trades intelligently and successfully, the underlying principles governing the use of all sharp tools must first be thoroughly understood and acquired by practice. Upon this knowledge as a basis the numerous details of forms and joints, of arrangement and adaptation of different materials, must then be accumulated by years of work and study to produce a mechanic in any one of the various pursuits.

Carpentry. - Of all the wood-working trades carpentry is the most general. It includes the cutting and framing of large timbers and rough planks and boards for building houses, bridges, trestles, piers, ship-frames, and the like. The form, size, and arrangement of the timbers necessary to resist the strains are designed by an engineer or architect, but the details, and especially those of the joints, must be determined and laid out by the carpenter. The woods made use of in carpentry are usually pine, hemlock, spruce, oak, and chestnut. The tools employed are the larger hand-saws, ax, adz, strong chisels, brace and large bits, hammer, and mallet; and for marking, a chalk-line, tape measure, large steel square, and carpenter's pencil, together with plumb-line or level; as a general thing, these complete the outfit.

Joinery differs from carpentry in that the work is smaller and made smoother; and the form, size, and joints established by experience and long usage are constructed to give a finished appearance as well as strength. All the commoner and fancy woods, together with bone, ivory, and some of the metals, are used in the many branches of joinery. The tools, besides those of the carpenter, include the finer saws, chisels, and gouges, the various forms of planes, smaller boring-tools, and measuring-tools, such as try-squares, bevels, gauges, compasses, and finely divided rules.

As necessary adjuncts to joinery we have turnery and carving, with modified forms of chisels and gouges for ornamental work; and painting for finishing and preserving work.

Some of the applications of joinery create distinct trades, such as cabinet and furniture making; stair, sash, and door making; pattern and model making; carriage and boat building, and cooperage - all of which require special woods and modified forms of tools adapted to the particular and various forms and joints peculiar to each.

In America there are many mechanics well versed in both carpentry and joinery of ordinary house-building, and who are known by the general name of carpenter.