Part 19 (1/2)

Varnish brushes need to be cleaned thoroly after each using. If they get dry they become too hard to be cleaned without great difficulty.

Brushes for water stains are easily taken care of by was.h.i.+ng with water and then laying them flat in a box. Cups in which the water stains have been used can also be easily rinsed with water.

Brushes for oil stains are most easily kept in good condition, by being hung in a brush-keeper, Fig. 245, (sold by Devoe & Reynolds, 101 Fulton St., N. Y. C.) partly filled with turpentine. The same brushes may also be used for fillers.

Oil stains should be poured back into their respective bottles, and the cups wiped out with cotton waste. When they get in bad condition, they can be cleaned readily after a preliminary soaking in a strong solution of potash. The same treatment may be given to brushes, but if they are left soaking too long in the solution, the bristles will be eaten off.

[Ill.u.s.tration: Fig. 245. Brush-keeper.]

EQUIPMENT AND CARE OF THE SHOP

REFERENCES:[*]

Murray, _Year Book_ 1906, p. 69.

Bailey, _M. T. Mag._, 9: 138. Dec. '07.

Robillion, pp. 48-90.

Hammacher and Schlemmer, pa.s.sim.

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

CHAPTER VII.

THE COMMON JOINTS.

Wherever two or more pieces of wood are fastened together we have what is properly called joinery. In common usage the term indicates the framing of the interior wood finish of buildings and s.h.i.+ps, but it is also used to include cabinet-making, which is the art of constructing furniture, and even the trades of the wheelwright, carriage-maker, and cooper. Since joinery involves the constant use of joints, a reference list of them, with ill.u.s.trations, definitions, uses, and directions for making typical ones may be of convenience to workers in wood.

HEADING JOINTS

_No. 1. A lapped and strapped joint_, Fig. 264, p. 177, is made by laying the end of one timber over another and fastening them both together with bent straps on the ends of which are screws by which they may be tightened. It is a very strong joint and is used where the beams need lengthening as in false work or in long ladders and flag poles.

_No. 2. A fished joint_, Fig. 264, is made by b.u.t.ting the squared ends of two timbers together and placing short pieces of wood or iron, called fish-plates, over the faces of the timbers and bolting or spiking the whole firmly together. It is used for joining timbers in the direction of their length, as in boat construction.

_No. 3._ In a _fished joint_, Fig. 264, keys are often inserted between the fish-plate and beam at right angles to the bolts in order to lessen the strain that comes upon the bolts when the joint is subjected to tension. In wide pieces and for extra strength, as in bridge work, the bolts may be staggered.

_Nos. 4, 5, 6 and 7._ _A scarf or spliced joint_, Fig. 264, is made by joining together with flush surfaces the ends of two timbers in such a way as to enable them to resist compression, as in No. 4; tension, as in No. 5; both, as in No. 6, where the scarf is tabled; or cross strain as in No. 7. No. 4 is used in house sills and in splicing out short posts, Nos. 5 and 6 in open frame work. _No. 7_ with or without the fish-plate, is used in boats and canoes, and is sometimes called a boat-builder's joint, to distinguish it from No. 4, a carpenter's joint. A joint to resist cross strain is stronger when scarfed in the direction of the strain than across it. No. 7 is the plan, not elevation, of a joint to receive vertical cross strain.

b.u.t.t JOINTS

_No. 8. A doweled b.u.t.t-joint_, Fig. 264, is made by inserting, with glue, dowel-pins into holes bored into the two members. The end of one member is b.u.t.ted against the face or edge of the other. It is used in cabinet-making where the presence of nails would be unseemly.

[Ill.u.s.tration: Fig. 246. Lay-out by Thru Dowling.]

In a doweled b.u.t.t-joint the dowels may go clear thru the outside member, and be finished as b.u.t.tons on the outside, where they show.

To lay out this joint mark near the ends of the edges of the ab.u.t.ting member, X, Fig. 246, center-lines A B. Draw on the other member Y, a sharp pencil-line to which when the lines AB on X are fitted, X will be in its proper place. Carry the line around to the other side of Y and locate on it the proper centers for the dowel-holes E and F. Then fasten on the end of X a handscrew in such a way that the jaws will be flush with the end. With another handscrew, clamp this handscrew to Y in such a way that the marks on the two pieces match, A to C and B to D, Fig. 247. Bore at the proper places, E and F, holes directly thru Y into X.

[Ill.u.s.tration: Fig. 247. Thru Boring for a b.u.t.t Joint.]