Rebated? Of Which The Section, Fig. 293, Explains Itself
Here a considerable shrinkage may take place, as at A, without causing an opening between the boards throughout their depth, but the joint is not an economical one and is seldom used.
Fig. 293. Rebated Floor.
Fig. 294. Rebated, Grooved and Tongued Floor.
Fillistered3 is another name for the joint shown in Fig. 293. Rebated, Grooved 4 and Tongued. - One board can first be nailed as shown at b, Fig. 294, and then the other board, upon being slipped into it, will be kept down by the form of joint. Thus the nails are prevented from appearing on the surface of the floor, which is sometimes desirable; the joint is however wasteful of material and troublesome to fit.
2 Rebating or Rabbeting is the cutting a rectangular slip out of the side of a piece of wood, as at A in Fig. 293. The re-entering angle left upon the wood is called the rebate or rabbet, or Sc. the check.
Fig. 295. Rebated and Filleted Floor.
3 Another meaning of the word fillistered is given at p. 138. 4 Grooving or Ploughing is the formation of a rectangular groove in a piece of wood to receive a tongue, as in Figs. 296, 297.
A rectangular rebate is cut out along the lower edges of the boards as in Fig. 295, and the space filled in with a slip or "fillet" generally of oak or some hard wood, about 1 1/4 inch or 1 1/2 inch by 3/16 inch in section.
It will be seen that any opening caused by shrinkage is covered by the fillet, and the floor must be worn down nearly through its whole thickness before the fillet is exposed, so that the joint is an economical one and is easily repaired.
A narrow groove is cut in the side of each board, and an iron or wooden1 tongue inserted (Fig. 296).
Fig. 296. Ploughed and Tongued Floor.
It will be noticed that this shares some of the advantages of the filleted joint, but the tongue is sooner laid bare when the floor is much worn. The tongue should be kept lower than the centre of the thickness of the boards, so that as much wear as possible may be got out of them before it is exposed. When wooden slip feathers are used they should have a coat of paint, and iron tongues should be painted two coats, or galvanised to prevent their rusting, swelling, and splitting the wood.
In this joint (Fig. 297) the tongue is worked upon one board to fit the groove cut in the other. This is not an improvement on the joint last described; the tongue is necessarily thicker, and thus causes a thinner piece of wood to be left above the groove. This rots and flakes away if the floor is often washed.
1 See remarks on slip feathers, p. 238.
Fig. 297. Grooved and Tongued Floor.
Small oak dowels are fixed along the edge of one board to fit into holes in the other (see Fig. 298).
The dowels should not be over the joists, but in the spaces between them, so that the edges of the boards are held down and kept flush, at short intervals throughout their length, by the nails at the joists, and by the dowels between.
Fig. 298. Dowelled Floor.
Dowelled floors show no nails on the surface; only one edge of each board is nailed obliquely, the other being kept down by the dowel.
Of the joints above described, those illustrated in Figs. 292, 293 are used chiefly for inferior floors; that shown in Fig. 295 for warehouses or barracks; those in Figs. 296, 297 for ordinary floors of a high class; and that in Fig. 298 for very superior floors.
The joints in Figs. 293, 294, 297 necessitate the use of a larger quantity of boarding to cover a given surface than when the other joints are adopted.