Practical Organ Building

by W. E. Dickson

Fig. 8.

Fig. 9.

Remark.—We confess to a strong liking for these later plantations, which require some little careful mechanical adaptations, but result in a compact arrangement, admitting of enclosure in a case of graceful outline.

Fig. 10.

5. We have still some considerations requiring careful attention before we can map out our sound-board. The plantation of the pipes will be the chief guide to the planning of the channels, with the divisions or spaces between them; but it must not be forgotten that the boring of the holes for the supply of air must be done in regular lines within spaces or widths easily covered by the sliders. A slider is seldom more than from 2 to 3 inches wide; there are good reasons why this width cannot conveniently be much exceeded. But the feet of the large pipes in the bass octave will be as much as 5 inches or more apart when the pipes are planted back to back, as in Figs. 5 and 6. Hence we must decide, before we begin to work, not only how the pipes are to stand on the board, but how they are to get their wind and be deprived of it by the action of a slider of the usual width. Perhaps we shall resolve to run two narrow sliders under the foot-holes of the whole stop, one for each of the two rows, controlling both sliders by a single knob or handle. By this method every pipe will stand on its wind, as the workmen say, that is, will be in direct and uninterrupted communication with the channel when the holes are open. Or possibly it may suit our plans better to run two sliders under the feet of the bass pipes, and a third between them, under the rest of the stop; all three, be it well understood, extending from end to end of the sound-board, but having holes only at the proper places, and being blank elsewhere: these three sliders being governed by one knob, or by two, if the stop is to draw in halves (as it is called), that is, as a separate Bass and Treble. Or, once again, we may use a single slider for the whole stop, but carry the wind through grooves fashioned in the solid wood from the holes bored in the usual way to the points at which the pipes are planted. And, lastly, we may carry the wind from the holes to pipes planted in any position, and practically at any distance by tubes made of pipe-metal or other material.

Remark.—It need hardly be said that an examination of the interior of a well-built organ will be of great service to the beginner who is planning his first sound-board.

6. The dimensions, then, and character of the sound-board having been determined after full consideration of the site for the organ, and a drawing or sketch having been made for your own guidance, proceed thus:—Take a board of good clean bay-wood, ½, ⅝, or ¾ inch in thickness, and long enough and wide enough to form the "table" or top of your work; and dress this carefully until one of its surfaces is quite true and level. This dressed or levelled side is to be the lower or under side, and we are about to form upon it the grooves or channels of which it will ultimately form the roof. Next prepare a ruler or straight edge of any thin stuff, and on this, with compasses, rule, and square, guided by plenty of deliberate consideration, mark the size and place of each of the grooves, and of the bar of wood which will divide each groove from its neighbour, from end to end. You will find, of course, and you were previously aware, that the widths of the grooves and the thickness of the bars will vary in proportion to their place in the scale. Let us say at once that ¾ inch will be ample width for the CC groove in our small organ; and let us advise that the smallest groove in the treble be about ¼ inch in width, and that the bars between these narrow grooves be at least ⅜ or ½ inch in thickness, in order to allow a good seat or margin for the pallets or valves which are to govern the admission of the wind. In the bass the bars will be very much thicker than this, or not, according to the plan which you have adopted. The part of your rule in which you will soon perceive that the chief danger of crowding your pipes will arise is the tenor octave. Refer carefully to your pipes, and be quite sure before you mark your ruler, that you are allowing room for Tenor C and its neighbours to stand clear of each other when they are planted on the completed board. Having satisfied yourself on these points, prepare your bars from sound pine-wood, planing them with care, and especially seeing that the edge of each bar is truly square with its sides. Two inches will be an ample width for each bar, in other words, an ample depth for each groove when completed. Their length will of course be equal to the width of the table, less an inch or so, according to the construction now to be described.