Handwork in Wood Part 15

(6) Punching Tools.

Barnard, p. 29.

Wheeler, p. 433.

Selden, p. 161.

(7) Gripping Tools.

For holding work: Goss, p. 63.

Wheeler, pp. 65-75, 475.

Selden, pp. 140, 147, 186, 194.

Hammacher, pp. 286-291.

For holding other tools: Goss, pp. 56-59.

Selden, p. 143.

(8) Measuring and Marking Tools.

Goss, pp. 9-20.

Griffith, pp. 9-19.

Hodgson, _The Steel Square_.

Wheeler, p. 465.

Tate, pp. 21-25.

_Building Trades Pocketbook_, pp. 234-237.

Selden, pp. 149, 150-152, 175.

Sargent's _Steel Squares_.

(9) Sharpening Tools.

Barnard, pp. 136-142.

Sickels, pp. 80-85.

Wheeler, pp. 480-488.

Selden, pp. 153, 162, 172, 180.

Goss, pp. 39, 64-69.

[Footnote *: For general bibliography see p. 4.]

CHAPTER V.

WOOD FASTENINGS.

The following are the chief means by which pieces of wood are fastened together: nails, screws, bolts, plates, dowels, glue, hinges, and locks.

NAILS

_Nails_, Fig. 226, may be cla.s.sified according to the material of which they are made; as, steel, iron, copper, and bra.s.s. Iron nails may be galvanized to protect them from rust. Copper and bra.s.s nails are used where they are subject to much danger of corrosion, as in boats.

Nails may also be cla.s.sified according to the process of manufacture; as, cut nails, wrought nails, and wire nails. Cut nails are cut from a plate of metal in such a way that the width of the nail is equal to the thickness of the plate, and the length of the nail to the width of the plate. In the third dimension, the nail is wedge-shaped, thin at the point and thick at the head. Unless properly driven, such nails are likely to split the wood, but if properly driven they are very firm. In driving, the wedge should spread with and not across the grain.

[Ill.u.s.tration: Fig. 226. a. Cut nail, common. b. Flat-head wire nail, No. 1, common. c. Finishing nail, or brad.]

Wrought nails are worked into shape from hot steel, and have little or no temper, so that they can be bent over without breaking, as when clinched. Horseshoe- and trunk-nails are of this sort. They are of the same shape as cut nails.

Wire nails are made from drawn steel wire, and are pointed, headed, and roughened by machinery. They are comparatively cheap, hold nearly if not quite as well as cut nails, which they have largely displaced, can be bent without breaking, and can be clinched.

Nails are also cla.s.sified according to the shape of their heads; as, common or flat-heads, and brads or finishing nails. Flat-heads are used in ordinary work, where the heads are not to be sunk in the wood or "set."

Some nails get their names from their special uses; as, shingle-nails, trunk-nails, boat-nails, lath-nails, picture-nails, barrel-nails, etc.

The size of nails is indicated by the length in inches, and by the size of the wire for wire nails. The old nomenclature for cut nails also survives, in which certain numbers are prefixed to "penny." For example, a threepenny nail is 1-1/4" long, a fourpenny nail is 1-1/2"

long, a fivepenny nail is 1-3/4" long, a sixpenny nail is 2" long. In other words, from threepenny to tenpenny 1/4" is added for each penny, but a twelvepenny nail is 3-1/4" long, a sixteenpenny nail is 3-1/2"

long, a twentypenny nail is 4" long. This is explained as meaning that "tenpenny" nails, for example, cost tenpence a hundred. Another explanation is that originally 1000 of such nails weighed a pound. The size of cut nails is usually still so indicated. Nails are sold by the pound.

The advantages of nails are that they are quickly and easily applied, they are strong and cheap, and the work can be separated, tho with difficulty. The disadvantages are the appearance and, in some cases, the insecurity.

The holding power of nails may be increased by driving them into the wood at other than a right angle, especially where several nails unite two pieces of wood. By driving some at one inclination and some at another, they bind the pieces of wood together with much greater force than when driven in straight.

The term brads was once confined to small finishing nails, but is now used for all finishing nails, in distinction from common or flat-headed nails. The heads are made round instead of flat so that they may be set easily with a nailset and the hole filled with a plug, or, where the wood is to be painted, with putty. They are used for interior finishing and other nice work.

[Ill.u.s.tration: Fig. 227. Tack.]

_Tacks_, Fig. 227, vary in size and shape according to their use; as, flat-headed, gimp, round-headed, and double-pointed or matting tacks, a sort of small staple. Their size is indicated by the word "ounce."

For example, a two-ounce tack is 1/4" long, a three-ounce tack is 3/8"

long, a four-ounce tack is 7/16" long, a six-ounce tack is 1/2" long, etc. This term once meant the number of ounces of iron required to make 1000 tacks.

Tacks are useful only in fastening to wood thin material, such as veneers, textiles, leather, matting, tin, etc. Tinner's tacks, which are used for clinching, are commonly called clinch-nails. Wire tacks, altho made, are not so successful as cut tacks because they lack a sharp point, which is essential.

[Ill.u.s.tration: Fig. 228. Corrugated Fastener.]

_Corrugated fasteners_, Fig. 228, or fluted nails, are used to fasten together two pieces of wood by driving the fastener so that one-half of it will be on each side of the joint. Their size is indicated by the length and the number of corrugations, as 1/2", four. They are often useful where nails are impracticable.

_Glaziers' points_ are small, triangular pieces of zinc, used to fasten gla.s.s into sashes.

SCREWS

(a) _Wood-screws_, Fig. 229, may be cla.s.sified by the material of which they are made; as, steel or bra.s.s. Steel screws may be either bright,--the common finish,--blued by heat or acid to hinder rusting, tinned, or bronzed. Bra.s.s screws are essential wherever rust would be detrimental, as in boats.

(b) Screws are also cla.s.sified by shape; as, flat-headed, round-headed, fillister-headed, oval-countersunk-headed, and square-headed screws. Flat-heads are most commonly used. There are also special shapes for particular purposes. Round-heads may be used either for decoration or where great drawing power is desirable. In the latter case, washers are commonly inserted under the heads to prevent them from sinking into the wood. Oval-heads are used decoratively, the head filling the countersunk hole, as with flat-heads, and projecting a trifle besides. They are much used in the interior finish of railway cars. They are suitable for the strap hinges of a chest.

The thread of the screw begins in a fine point so that it may penetrate the wood easily where no hole has been bored as is often the case in soft wood. The thread extends about two-thirds the length of the screw. Any longer thread would only weaken the screw where it most needs strength, near the head, and it does not need friction with the piece thru which it pa.s.ses.

The size of screws is indicated by their length in inches, and by the diameter of the wire from which they are made, using the standard screw-gage, Fig. 220, p. 117. They vary in size from No. 0 (less than 1/16") to No. 30 (more than 7/16") in diameter, and in length from 1/4" to 6".

[Ill.u.s.tration: Fig. 229. a. Flat-head Wood-screw. b. Round-head Wood-screw. c. Fillister-head Wood-screw. d. Oval-countersunk-head Wood-screw. e. Drive-screw. f. Square-head (lag- or coach-) Screw.]

The following is a good general rule for the use of screws: make the hole in the piece thru which the screw pa.s.ses, large enough for the screw to slip thru easily. Countersink this hole enough to allow the head to sink flush with the surface. Make the hole in the piece into which the screw goes small enough for the thread of the screw to catch tight. Then all the strength exerted in driving, goes toward drawing the pieces together, not in overcoming friction. The hole must be deep enough, especially in hard wood and for bra.s.s screws, to prevent the possibility of twisting off and breaking the screw. Soap is often useful as a lubricant to facilitate the driving of screws. Where it is desirable that the heads do not show, a hole may first be bored with an auger-bit large enough to receive the head and deep enough to insert a plug of wood, which is cut out with a plug-cutter, Fig. 131, p. 84, and glued in place. If pains are taken to match the grain, the scar thus formed is inconspicuous.