[Ill.u.s.tration: Fig. 268.
52 Miter 53 Doweled miter 54 Spline miter 55 Slip feather miter 56 Slip dovetail miter 57 Double dovetail keyed 58 Ledge and miter 59 Stopped miter 60 Double tongue miter 61 Stretcher 62 Strut 63 Square thrust 64 Oblique thrust]
[Ill.u.s.tration: Fig. 269.
65 Brace 66 Housed brace 67 Oblique mortise and tenon 68 Bridle 69 Bird"s mouth 70 Glue 71 Rabbeted 72 Matched 73 Beaded 74 Spline 75 Doweled]
CHAPTER VIII.
TYPES OF WOODEN STRUCTURES.
The articles suitable to be made in wood with hand tools may for convenience be divided into four general cla.s.ses: (1) Unjoined pieces; (2) board structures; (3) panel structures; (4) framed structures. A few ill.u.s.trations of each cla.s.s are given below.
(1) SIMPLE OR UNJOINED PIECES
Of these there are a number that are advantageous for the learning of tool processes; at the same time they give opportunity for expression in design, and when finished are of use.
Examples are: key-boards, chiseling-boards, bread-boards, sleeve-boards, ironing-boards, coat- and skirt-hangers, and gouged trays. Some of these are so simple as to include hardly any process but planing, directions for which are given above, p. 72.
[Ill.u.s.tration: Fig. 270. Pen-Tray.]
Where there is more than one process involved, the order of procedure is of importance. In general, a safe rule to follow in each case is to plane up the piece true and square, or, in technical language, to "true" it up. At least as many of its surfaces should be trued as are necessary for the "lay out." Where the piece is to be rectangular all the surfaces should be true; where some of the surfaces are to be curved it is unnecessary and a waste of time to square them first. For example, in making a gouged tray with curved outline, Fig. 270, the working face, the working edge, and the thickness should all be true before the plan is laid out. Then, after the outline is drawn, the trough may be gouged, the outline cut with turning-saw, chisel, and spokeshave, and the edges molded with the gouge or chisel. If there is incised decoration it should be cut before the molding is cut, so that while being incised, the piece will lie flat without tipping.
These simple pieces, as well as others, are often embellished by _chamfering_. A chamfer is a surface produced by cutting away an arris. It differs from a bevel in that a bevel inclines all the way to the next arris, while a chamfer makes a new arris, Fig. 271. A thru chamfer extends the whole length or width of a piece, while a stop chamfer extends only part way. For the laying out of a chamfer see p.
115.
[Ill.u.s.tration: Fig. 271. Difference Between Chamfer and Bevel.]
Thru chamfering is best done with a plane, Fig. 272. For this purpose the piece may be held in the bench-vise and the plane tipped to the proper angle, or the piece may be held in a handscrew which in turn is held in the vise as in Fig. 175, p. 102. The chamfers with the grain should be planed before those across the grain.
[Ill.u.s.tration: Fig. 272. Thru Chamfering.]
In chamfering a four-square stick into an eight-square, the piece may be gripped in the vise diagonally, Fig. 273, or it may be held in a trough made of two strips of wood from each of which an arris has been chamfered and then the two nailed together, Fig. 274. A dowel or nail may be inserted in the trough for a stop. Stop chamfers are pared best with a chisel, Fig. 275, held according to convenience either flat side or bevel side up. See under chisel, p. 53.
[Ill.u.s.tration: Fig. 273. Piece Held in Vise to Chamfer.]
[Ill.u.s.tration: Fig. 274. Trough for Planing Chamfers.]
[Ill.u.s.tration: Fig. 275. Stop Chamfering.]
(2) BOARD STRUCTURES.
These include such pieces as wall brackets, sets of shelves, book-racks, plate-racks, drawing-boards, foot-stools, taborets, and boxes.
The advantage of this form of construction is that it is comparatively easy to make; the disadvantage is that if the boards are wide, they are sure to shrink and swell. It is wise in all such work to true and smooth up all the pieces at once, and if the wood is not thoroly seasoned, to keep the boards under pressure till they are a.s.sembled.
In the case of several boards to be jointed into one piece, they should be glued together before the surfaces are smoothed. Suggestions regarding a few typical pieces follow:
_Wall Brackets._ (1) There are three essential parts, the shelf, the support or supports, and the back: the shelf to hold the articles, the support to hold up the shelf, and the back to hold all together, Fig. 276, _a_. The grain of the wood in the shelf should run left and right, not forward and back, because thus it rests on the support in such a way as not to break easily, and it also acts as a stiffener for the back. In case the back extends above the shelf, as in Fig. 276, _a_, the shelf can be secured firmly to the back, since there is side grain in which to drive nails or screws. As to the direction of the grain of the support and the back, this should run in the direction of the largest dimension of each. Where the back is long horizontally, for security in hanging, it is better to have two supports.[10]
[Footnote 10: See the School Arts Book for Nov., 1906, "Design in the Woodworking Cla.s.s," by Anna and William Noyes.]
[Ill.u.s.tration: Fig. 276. Wall Brackets, Double-Hung: _a_. Single Support. _b_. Double Support.]
_Wall book-shelves_, Fig. 277, _plate-racks_, etc., are simply compound brackets. The shelf is the essential piece, the sides take the place of the supports, and the back is often reduced to strips merely wide enough to give rigidity.
The shelves may be either gained into the supports, Fig. 266, No. 28 or No. 29, p. 179, or a keyed mortise-and-tenon may be used, Fig. 277.
In the latter case the back strip may have a short barefaced blind tenon which is mortised into the upright, Fig. 278. It also fits into a rabbet on the upper back side of the shelf. Made in this way the shelves can be knocked down easily.
[Ill.u.s.tration: Fig. 277. Wall Book-Case.]
[Ill.u.s.tration: Fig. 278. Construction of a Knock-Down Book-Shelf Seen From the Back.]
_Foot Stool or Cricket_, Fig. 279. The grain of the supports should run up and down, because pieces with the grain horizontal would be likely to break under pressure. Braces or a rail give additional support. The top should not be larger than the base of the legs; otherwise a person standing carelessly on the stool is in danger of being upset.
[Ill.u.s.tration: Fig. 279. Cricket.]
_A Drawing-Board_ is made up of narrow boards, with glued joints, with the boards so laid that the annual rings will alternate in direction, Fig. 280, _a_. It must be made so that it can shrink and swell and yet remain flat. For the purpose of giving lateral stiffness cleats are added. They may simply be screwed on the underside, the screw holes being large enough to allow for shrinkage, or they may be dadoed in with a dovetail dado, Fig. 280, _b_, or they may be grooved to admit a tongue on the end of a board, Fig. 280, _c_. In this case screws pa.s.sing thru large holes in the cleats hold them in place.
[Ill.u.s.tration: Fig. 280. Drawing-Board Construction: _a._ With Cleats Screwed on Beneath; _b._ With Cleats Dovetail-Dadoed in; _c._ With Cleats Matched on Ends.]
_Taborets._ The term taboret originally meant a little tabor or drum, and was therefore used to designate a small stool, the seat of which consisted of a piece of stretched leather. The term now includes small, tablelike structures for holding flowerpots, vases, etc. It might more properly be called a "table-ette."
When made up with boards having their long edges mitered, it has from four to eight sides. A six-sided one is shown in Fig. 281. In making, it is best to fit the joints exactly first, while the board is stiff, and then to cut out the pattern of the legs. Directions for gluing are given on p. 169.
[Ill.u.s.tration: Fig. 281. Taboret.]
_Sc.r.a.p-boxes_, Fig. 282, _and flower-pot boxes_ may be made with the same construction.
[Ill.u.s.tration: Fig. 282. Sc.r.a.p-Box.]
_Rectangular Boxes._ There are various methods of joining their sides.
The b.u.t.t joint, Fig. 264, No. 11, p. 177, is plain, simple, and good for coa.r.s.e work. This joint may be reinforced as in packing boxes, Fig. 283.
[Ill.u.s.tration: Fig. 283. Reinforced b.u.t.t Joint in Box.]
Mitered joints, Fig. 268, No. 52, p. 181, are neat but weak, unless reinforced by a spline, Fig. 268, No. 54.
The rabbet or ledge joint, Fig. 266, No. 24, p. 179, is both strong and neat. It can be glued and also nailed if desired.
The rabbet and dado joint, Fig. 266, No. 26, can be glued without nails and is good for small boxes.
The housed dado, Fig. 266, No. 25, is good for water-tight boxes.