There are now two methods of proceeding. First method:—The table being turned over, with the dressed side uppermost, your ruler well in sight, with plenty of hot and fresh glue fix your first thick bar at or near either end of the table. We say, "or near either end," because you may like to leave room for a finishing cheek of mahogany when all the bars are put in. The second bar will be glued to the table in like manner, the proper distance from the first being secured by "filling-in pieces" of wood of the exact thickness, glued between the bars at their ends. This alternation of bars and fillings-in will be continued until all the grooves have been formed according to your ruler; the rough ends of the bars will then be dressed with a sharp plane, and neat cheeks of stout bay-wood will be glued on all the four sides of the divided box which you have thus built up. Second method:—Prepare the bay-wood cheeks first, and in the two long ones, using a fine saw and small chisel, cut grooves to receive the ends of the bars. Form a shallow box by gluing these bay-wood sides and ends to the table. The corners need not be dovetailed, but an equally close joint must be secured if dovetailing is omitted. Then introduce the bars, using an abundance of hot glue, and taking care that no bar fits so tightly between the cheeks as to risk bending. When all the bars are glued in, add more thin glue within each groove, placing the sound-board in a sloping position that the glue may run into the angles, and afterwards reversing the board to the opposite slope, repeating the coating of thin glue.
Remark.—This unusual profusion of glue is to preclude the possibility of air making its way from one groove to the adjacent one bypassing between the edge of the bar and the table; and what is here said applies equally to both methods.
We ourselves prefer the second method to the first. M. Hamel, in his wonderfully accurate and minute treatise, describes a third, in which the fillings-in are avoided. Those to whom his book is accessible cannot fail to share the present writer's admiration of his marvellous industry, and of his great gift of clear and precise description of mechanical processes. Hopkins and Rimbault may also be consulted with much advantage.
7. The work, thus glued up, must be left in a dry room for two or three days, until all is perfectly set and hard. Meanwhile the other pieces of which the completed sound-board will consist are being cut out and prepared. We shall want the upper boards, the sliders, and the slips of wood (false sliders the French builders call them, while in England they are termed bearers) which divide these from each other.
We may safely suppose that if the ordinary form of sound-board has been chosen—such, for instance, as that which is shown in Fig. 6—its size will be about 4 feet, or 6 inches more, in length. Its width will depend on the number of stops for which it is planned, and therefore of sliders which are to work on the table; if we are to have five stops, about 15 inches may be taken as the probable width, but this may be less, or more, according to the class of stops selected, and the arrangement chosen for their bass pipes. To give accurate measurements in feet and inches for all the parts of the sound-board would only mislead our readers at this stage of our labours. We give general rules only: it must rest with the reader himself, as we have now abundantly reminded him, to decide on the shape of his sound-board and to make the plantation of his pipes, and the consequent arrangement of grooves and sliders conformable thereto.
Assuming, then, quite arbitrarily, and independently of all special considerations, that the sound-board is 4 feet long and 15 inches wide, we may cut out the upper boards from sound and clean bay-wood, 1¼ inch thick. Cut them 6 inches longer than the sound-board. And now as to width. As there are five stops, and five sliders for them, are we to understand that we shall have also five upper boards? To this we reply, by no means. Our stops, we assume, will be two of 8 feet, two of 4 feet, and one of 2 feet. For reasons which we shall soon give, we shall propose to have one upper board for each of these three divisions: that for the 8-feet stops being 7 inches wide, that for the 4 feet 5 inches, and for the 2 feet 3 inches. Under the 7-inch board there will be two sliders, each 2 inches in width; under the 5-inch, two sliders, each 1½ inch in width; and under the 3-inch, one slider, 1¼ inch wide. The bearers will be thus:—The two outside bearers, that is, those which extend along the front and back margins of the sound-board, to be 1¼ inch in width; the second bearer (reckoning from the back) to be 1 inch; the third to be 1½ inch, because it will lie beneath the line of junction, or rather of division, between the two wider upper boards; the fourth bearer may be ½ inch only, being merely a separation between the next two sliders; the fifth may be 1¼ inch, falling as it does under a line of division; the sixth is similar to the first. It will thus be seen that we have—
| 2 | sliders, | 2 | inches | each | = | 4 | inches |
| 2 | " | 1½ | " | " | = | 3 | " |
| 1 | " | 1¼ | " | " | = | 1¼ | " |
| 3 | bearers, | 1¼ | " | " | = | 3¾ | " |
| 1 | " | 1½ | " | " | = | 1½ | " |
| 1 | " | 1 | " | " | = | 1 | " |
| 1 | " | ½ | " | " | = | ½ | " |
| — | |||||||
| Total width | = | 15 | inches. |
Remark.—All this is so important that we have shown the measurements drawn to scale in Fig. 11.
Cut out the sliders and bearers from perfectly clean sound bay-wood or red cedar boards, not more than ⅜ inch in thickness. Having turned your sound-board over, with the table uppermost, assemble all the pieces, and satisfy yourself that your measurements are correct, and that so far there is no error in your plans. See that all your planes are in first-rate order, and set yourself in earnest to bring to a perfectly level and true surface the table or top of the sound-board, and one side of the sliders and bearers. No pains must be spared to render the surface of the table absolutely true. Apply a "straight edge" rubbed with chalk, moving it in various directions, and use unwearied diligence in removing all inequalities detected by this means. Take care, too, that there is no "winding." In short, adopt all the means which the rules of good joinery give you for producing a surface faultlessly level. This done, arrange upon the table, with their planed sides downwards, your sliders and bearers, and pin them down upon it with very small brads, piercing through near their edges. In doing this have regard to the grain of the wood, as you are about to dress the upper surfaces. Sink the brads well out of the way of the plane with a punch, and bring the sliders and bearers to a true level as you did the table.