End of plain sawed board
Kiln-dried Lumber.—This bending and twisting of the boards does not take place as soon as they are sawed out of the log, but gradually during the process of seasoning; and, unless the lumber is kiln-dried, the more gradual the seasoning the less the bending. Lumber is kiln-dried by stacking it, with air spaces left between the boards, in steam-heated closets or kilns, where the process of drying is carried on evenly though rapidly. Kiln-dried lumber, therefore, retains its shape quite as well as that which is dried slowly in the lumber pile. But whether kiln-dried or not, it should be allowed to remain in a dry place as long as possible before using it so that it will have a chance to change all that it is likely to and so lessen the subsequent shrinking and warping. A good cabinet-maker never undertakes to make furniture from stock that he does not know to be perfectly dry and well seasoned, not only because unseasoned lumber is more likely to shrink, warp, and crack, but also because it cannot be depended upon to hold the glue, take varnish well, or respond readily to other methods of finishing.
Planing Down to a Flat Surface.—Since boards are seldom perfectly flat, even if one has taken the greatest pains to select well-seasoned stock, it will almost invariably be necessary to work them down to a plane surface when they are glued up or joined together in any way. To accomplish this result it is necessary to plan the arrangement of the pieces in such a way that the concave of the bend shall fall on the same side, as shown in the illustration, and thus provide for the final working down with the least possible removal of stock. They can be arranged on a level bench top or floor with the convex side down so that they will lie as flat as possible. The boards should then be taken out one by one and their edges should be carefully planed so that they will match together in the position in which they are laid. It will be necessary to take each board from its place and return it several times in order that this matching may be made as perfect as possible. The object of all this is to prevent the entire arrangement from springing—i. e., from acquiring any new bend or twist when the parts are glued up. In joining boards to form large pieces of glued-up work, like table tops, it is customary to strengthen the joints by means of dowel pins. Small table tops and similar work may be safely glued up without dowelling.
Boards placed for planing to flat surfaces
Fastening Glued-up Work. It will be readily understood upon a little reflection that all plain glued-up work should be allowed to move slightly upon the framework to which it is attached; for even after it is well seasoned and well finished all woods will swell slightly in a damp atmosphere and shrink slightly when the air is dry, the greatest movement being across the grain. Solid table tops, therefore, should never be fastened down firmly upon the framework with glue or with screws, but should be secured by means of buttons screwed to the under side of the top which travel in grooves cut in the framework and thus allow for expansion and contraction. A drawing is shown to illustrate the method of attaching the table-top buttons. Much of the warping and splitting of furniture is due to the failure of the designer or maker to observe this precaution.
Method of fastening table tops
In planing up stock, whether it be a single piece or several glued together as just described, the cabinet-maker planes off one side first and then, using this side as the working face, gauges to the required thickness and planes off the other side if necessary. If the work be upon glued-up stock, it is well to plane off the projecting edges of the concave sides first, as that is generally somewhat easier and may be all the planing that will be necessary. If it be single pieces of stock that need to be planed up, the natural twist or "wind" is first planed out to a flat working face on one side before putting the plane to the opposite side.