Fig. 49.
Method 3.—In small organs, with short sound-boards, the iron trundles may be made to act at once upon the sliders, without the intervention of the levers and bridge. When this is done the upper arm of the trundle will be quite at its top, and will be sloped or bent upwards as shown in Fig. 49. Near its end will be a short and strong pin, which will enter a little slot or oblong hole in the slider. The trundle will revolve in a wooden collar screwed to the cheek of the wind-chest, and at its base in a hole in a bearer or in the organ-frame as before. The draw-bar will act directly upon the lower arm of the trundle, and the lengths of the two arms must be proportioned to each other, so as to compensate for the difference between the play of the slider and that of the draw-stop.
Cases of peculiar construction may be easily imagined, in which two sets of trundles may become necessary, communicating with each other by long traces. In some other cases the trundles may be horizontally placed, like a roller-frame, and common squares may act upon the sliders; with upright traces connecting them with the arms of the horizontal trundles; while combinations of these various plans will suggest themselves to the inventive reader to meet possible exigencies of position or arrangement.
Method 4.—We may still further explain that trundles may be discarded by fixing common squares or bell-cranks upon steps or stages cut on the edge of a piece of thick plank, screwed to the organ-frame, the steps or stages corresponding to the levels of the draw-stops as arranged in the cheeks or jambs of the organ. The draw-bars will act directly on these squares, which will transmit the movement to the levers by traces; but in this case it is plain that the levers will be of varying lengths, and must be provided with separate bridges, in order that the proper relation may be maintained between the play of the several parts. This plan has much to recommend it.
We have entered at some length into the subject of the draw-stop action, because much of the comfort of the player depends upon its efficiency. The arrangement to be adopted should be well considered, and the plans for it matured at an early stage of the work. All the pins used should fit accurately, and it is well that means should be taken to prevent the dropping or working out of these pins. A very neat way of guarding against this common accident is to reduce a small portion of the end of the pin with a file or in the lathe, and to cut a screw-thread upon this reduced portion; a leather button will then render failure impossible. The other end of the pin is usually bent down at a right angle.
Composition pedals, for drawing and shutting off the stops in groups by the foot, are not wanted in so small an organ as ours, and we need not describe them.
CHAPTER XI.
PEDALS.