S5. Centre spot of the Ｄ.
S6. Right spot of the Ｄ.
Holes are bored in the sides of the slates and metal dowels leaded into one side, as shown in the sketch (fig. 17), so that each slate may fit into the next, and then large holes are drilled out on the underside of the slates and steel nuts leaded in to take the long screws which fasten the cushions firmly to the slates (fig. 18).
Fig. 18
On the underside of each slate a bevel about two inches wide is made, in order that a chisel may be slipped between the slates to separate them when dismantling a table; and if one is far away from professional assistance, and is obliged to take down a table according to one’s own lights, it is well to look carefully for this bevel, and it may save many a cracked slate.
Various thicknesses are used, from, say, 1⅛ inch up to and over two inches, the general principle being that, the thicker the bed is, the quieter the balls run. But, as in most other things, there is a reasonable limit, because the weight of the slates increases so enormously with the increased thickness, that beyond two inches in thickness they become very difficult to handle, and the risk of damage in transport is more than proportionately increased.
Therefore, one may call two inches a reasonable maximum, and 1⅝ in. a fair minimum for the thickness of slates.