Practical Organ Building

by W. E. Dickson

Fig. 47.

Fig. 47 shows these squares or bell-cranks arranged upon a board which is screwed upon the key-frame. They may be cut out of sheet iron or may be made of oak, the arms halved together or joined by tenon and mortice. They should work upon a strong pin of iron or brass, and a small block underneath each square lifts it above the level of the board. A trace, or light rod of pine, 1 inch or ⅞ square, notched at one end to receive the arm of the crank, and at the other to catch the end of the lever, is connected with each by a pin of iron or brass, and blacklead is used as before.

The draw-stops are generally turned and polished for a few inches at the end which appears in sight, and which carries the knob, and it is usual to line the holes through which this turned and polished part protrudes with scarlet or other cloth. The tails of these draw-bars, left square, should work in guides cut in a vertical piece at the back, or otherwise arranged to ensure parallel movement. A short slip of hard wood or of metal connects each draw-bar with its bell-crank. The action of this mechanism must not be considered satisfactory unless each stop operates with ease and exactness, and without any sense of elasticity or unequal resistance.

The knobs will be easily fashioned, from a good pattern, by any turner possessing a light lathe; nor is it difficult to engrave the names on the ivory faces. A convenient tool for this latter purpose may be made by grinding down the end of a small triangular file. But the engraver's "burin" may be bought at the tool-shops. The knobs will not be glued into the ends of the draw-bars until all is complete, that the engraved titles may be rightly adjusted at a true level.

Method 2.—If it is preferred to place the draw-stops to the right and left of the player, as in large organs, we shall have the bridges and levers as before. The draw-bars will run through guides at the back, fixed to some part of the frame, and their polished ends will be brought through lined holes in the cheeks of the case, fitted according to taste. The connection of these horizontal draw-bars with the vertical levers will be effected by squares or bell-cranks of a form known as "trundles." We give a representation of one of these in Fig. 48, where a is the slider, b the lever acting upon it, c the trace connecting it with d, an arm of the trundle e f. This trundle should be of oak, birch, or other hard wood; it has pins at each end, which are received into holes bored in bearers arranged accordingly, and not shown in the figure, or in the frame itself of the organ. (It is well to char these holes.) The trundles are of course placed parallel to each other in a row, and the second arm of each trundle will be inserted at the level answering to the position of the draw-bar. In the cut g h is this second arm and draw-bar.

Fig. 48.

The trundles are easily made of iron, and with manifest increase of strength and neatness. We have used gas-pipe for this purpose, ½ inch in external diameter. The arms made from iron slips, ½ inch wide and ¼ thick, were brought to a round pin at one end in the lathe. This round pin passes through a hole drilled through the trundle (whether tubular or solid), fitting it tightly, and the projecting end is spread out with a riveting hammer. All this may be done cold, but still more effectually with the aid of a forge. The ends of the trundle will be received in charred holes in bearers as before, using tallow as a lubricator; or if tube is adopted, brass or iron pins may be jammed into the ends of the tube, and trued up in the lathe. All such iron-work, introduced here or elsewhere in the organ, may be painted over with the composition known as "Brunswick black varnish," which will prevent rust. The holes in the arms, to receive the pins of the traces and draw-bars, will be drilled with ease in the ever-handy lathe, or with a bow and breast-plate, or by any blacksmith.