Windchest. The windchest of a great organ , and in general any organ chest , is the part on which the pipes are lined up, and which controls the wind to them.

A windchest is made up of several parts. To make a windchest , take Holland or Vauge [Vosges] oak lumber (the drier the better), saw it to width and shape it; that is, plane it smooth. Leave it three weeks or a month in a place like an attic or loft exposed to the variations in air temperature and their effect.

When the lumber has reached a stable condition, carefully dress it on all four sides, and use it to make a frame, ACBD [Organ Plate II] fig. 2 , where sides AC and BD are called the depth of the frame and sides AB and CD are its length ; [1] the latter sides are notched on the inside, as at HF; the notches as well as the spaces, K, between them follow the scale. See Scale. After the two long sides of the frame have been notched and joined with dovetails or mortise and tenon, bars GH FE are made, as long as the frame is wide, and squared to the width of the notches, into which they must fit exactly. The bars are secured in their notches by glue and finish nails. The bars and the spaces between them, the channels, must follow the scale: the notches, as we have said, are the same width as the bars, which must fill them exactly, and the spaces between them must be the same width as the channels corresponding to them.

Once the frame and the bars are joined together, the top and underside are dressed, and a table, abcd , fig. 3 , is applied to the top. This table is also made of Holland oak, glued and nailed to the frame and bars. When the table is glued and dry, the chest is turned over so that the channels face upward, and a whole cooker of glue is poured into them, to coat and seal all the joints and pores in the wood. This operation is repeated as many as three times, seeing to it that the first coat is very light, the second a little stronger, and the third one rather thick.

When the glue coatings are dry, sponsels x x , fig. 2 , are fitted between chest bars HGEF ; these pieces of wood are only one or one and a half lignes  [2] thick and are flush with the bars; they must be distant from the front rail, Hx Fx , by the length of the pallets, minus four lignes .

After the sponsels have been glued in, strips of vellum ( See Vellum) are glued onto the area marked ABxx , fig. 2 . The vellum strips cover the front rail AB, parts Hx, Fx, Bx of rails HG and FE, and sponsels xx , thus defining the pallet area. When the strips of vellum are glued and dry, sheepskin is glued on the whole area xxDC , which including the pallet parchment completely covers the underside of the windchest . To stretch the skin and warm the glue, a rag is soaked in boiling water, then squeezed out before rubbing it on the sheepskin, which allows it to be stretched at will. See [fig. 4], NLEM . [3]

To make the pallets, take very dry Holland oak, then dress and true it on all sides. Pallets must be four lignes longer than opening Kx, fig. 2 , and four lignes wider than the channel they are to cover. Then the sides are beveled, so the two long side surfaces, DC, fig. 8 , and the one opposite, are only one or one and a half lignes from saw kerf ao on the pallet; surface EoD is given a similar slant, and opposite it, towards the tail, one of forty-five [degrees]. Then a wire ring must be mounted at the forward end of each saw kerf oa (fig. 6), after which the pallet is finished. Then a piece of sheepskin, A, fig. 8 , is glued underneath by the hair side, with the flesh side exposed; this piece of leather must be one or one and a half inches longer than the pallet, extending by that amount beyond the tail. The pieces of sheepskin glued to sponsels xx (fig. 2) act as hinges for the pallets, to the tail or rear surface of which a piece of the same skin is glued, covering the surface and hinge CB ( fig. 8 ). This piece keeps the pallet from coming unglued from the sheepskin that covers the lower surface. Before the pallets are installed in their places, the vellum that covers the channels here is cut away with a knife, as seen in openings aaaa in fig. 4 . After the pallets are glued on, as seen at bbb , [4] a brass or iron pin, ccc , is placed beside each one near the forward end; these pins guide the pallet in its motion so that it always returns to opening a on the channel.

When the pallets have been made and mounted on the chest , a box, FE , fig. 9 [ FF, fig. 6 ], called the pallet box , is made, to enclose them. It has only three sides: side F, figs. 6 and 9 , is an oak board three or four inches wide and as long as the chest . This board is joined and glued to sponsels x [fig. 2], to which the pallet leather is also glued. Side F , opposite this board, is called the bung board ; it consists of two boards, rabbeted to half their thickness along all four edges. This is done with a rabbet plane; see the cross-section in fig. 6 , and figs. 9 and 10.  [5] The front edges of the pallet box are lined with leather glued by the hair side to the edges facing the inside, to seal it. Each bung board has two handles, GG, fig. 7 , which allow it to be removed when a pallet needs attention. The bung boards are held in their seats by iron latches, p , fig. 7 . The bottom of the pallet box, opposite the pallets, is joined with tongue and groove to the back, E , of the pallet box, and with mortise and tenon to the three boards, EFE , [6] that together with the chest form the two rabbeted openings where the two bung boards fit. Inside the bottom of the pallet box a wooden rail is glued, m , fig. 6 , as long as the inside of the pallet box. This rail has saw kerfs across it, mmm , fig. 7 , parallel to the pallets and placed directly opposite those on the pallets; these saw kerfs, on the pallets and on rail m , called the spring rail , hold springs, fge , figs. 6 and 9 . These springs, of the most elastic brass that can be had, are shaped like a capital U; the ends are hooked outward and enter holes fe , one in the pallet kerf and one in the guide kerf opposite. These springs, bearing against the guide rail, hold the pallet against the chest . Between guide rail mmm and the bung board there must be holes for the purses, de [fig. 5, No. 3], connected to the pallets by S-hooks, ef, linked at one end to rings f on the pallets, and at the other to the upper rings, e , of the purses. See Purses. The pallets are opened by the keys by means of the trackers running from the purses to the roller board, and others running from the roller board to the manual keys. See Rollerboard. One end of the pallet box is closed, and the other has a square opening, ED , [Plate III] fig. 14, rabbeted like the openings for the bung boards; this opening receives the wind trunk that comes from the bellows. See Bellows and Wind trunk.

The top of the windchest table is fitted with as many strips, HH, fig. 7 , plus one, as there are to be stops on the chest. These strips, which are very thin, are glued and tacked to the table, and they must lie across the channels; they are called slider spacers. See Slider spacer. The sliders or registers (from regere, rego , govern, because they govern the wind that animates the organ) are thin strips of very dry wood; they must fill the width between the spacers and slide easily between them; on the underside of the sliders sheepskin is glued by the hair side, with the flesh side facing the table, where the slider is to rest. Flemish builders do not usually face the sliders with leather, but they dress the table of the chest and the slider so carefully that the wind finds no passage between them. The method of facing them with leather is preferable because the slightest warping or shifting of the wood lets the wind go from one hole to another, which produces an intolerable cipher. [7]

After the sliders are placed on the chest between guides HH , they are evened to the height of the guides, and they are fitted with shoulders. Shoulders NO MO are wooden pieces as wide as the sliders, glued to the ends, which must stand clear of the chest by one-half foot at each end; the shoulders must leave between them a length, OO, fig. 11 , equal to the overall length of the chest , AB , plus half the distance between the center of one channel and the center of the one next to it. On top of the sliders and guides a table is mounted, abcd , figs. 9 and 10 , of Holland or Vauge oak, called the toeboard ; The toeboards are at least one-inch thick and have hemispherical sockets to receive the feet of the pipes. See Foot (organ pipe) . The toeboards must be secured to the chest by pegs at each corner. To find the locations of the pipes on the toeboards, lines ux , fig. 10 , are drawn. These lines must correspond to the center of the channels, and lines cd [and y fig. 10] must correspond to the center of the sliders. To locate the first lines, before the table is glued to the bars, points st must be marked on the long sides of the chest , corresponding to the channels; then divide space st in two equal parts at r , use a carpenter’s square to draw line ru [and x ] perpendicular to the length of the toeboard, do the same at the other end, x, and at all the channels; then draw lines ux ux , corresponding to the center of the channels. To draw the other lines, Zy , mark on the ends of the toeboard the ends of the guides, and divide the space between them into two equal parts; using the dividing points, draw lines Zy Zy , which will correspond exactly to the center of the sliders; the intersection of lines ux, Zy are the places where holes must be bored vertically to meet the channels to which they must lead. The toeboard, the slider, and the table must all three be bored. Note that one of the shoulders must rest against the chest table; the other is the shoulder that engages the drawstop backfall ( see Drawstops); it must stand clear of the chest by half of space uu or xx , which we have said is the excess length, OO , of the slider, fig. 11 , over that of the chest table. Once the holes are bored, they are enlarged and burned with hot irons to clean them. The bass holes, which must have a certain size, are squared under the toeboards to half the thickness of the board; in the other half-thickness, they are rounded to fit the toes of the pipes. The holes in the sliders and the table are squared through both these parts; they are cut with a chisel, which is why they are square, but their shape is unimportant; they are cut with a chisel because it would be difficult to burn them with an iron large enough to enlarge them; the great heat of a large iron could split the wood. A slider is open when its holes align with those in the table and the toeboard, which opens the path from the channel. See DDD, fig. 12 . It is closed when the drawstop is pushed in, so the spaces between holes abcdef , fig. 11 , lie between the corresponding holes in the table and the toeboard, see CC, fig. 12 ,  [8] preventing the wind in the channel from reaching the holes in the toeboard. As for the arrangement of the stops, note that a stop is placed on a single slider along the length of the chest . The first stop is placed on the front of the chest , towards the pallet box, marked I, [Plate II] fig. 9 , is the Montre 16’; next, on the toeboard marked II, [9] the Bourdon 16’ or 8’ stopped. See the article Stops and the specific articles [on these stops], then the Grand Cornet, and according to the following table.

To avoid confusion among such a large number of stops, the great organ chest is made in two parts, and the basses are located towards the outer end of each part, near the drawstop backfalls, so the largest pipes are towards the sides of the organ and the smaller, higher-pitched ones in the middle, where a bridge is made on which the chests are placed for the Cornet and Trompette de Récit, and sometimes also the toeboards for the Fourniture and Cymbale , when they are not placed on the windchest . See the articles on these stops.

To hold all these stops upright on the toeboards, in holes where they are merely standing, rackboards AbCd , fig. 14 , are added; [11] these are thin pieces of Holland oak with as many holes, ee , as there are on the toeboard; the holes are made with a tapered bit and must be large enough for pipe HK to fit; they also must be centered vertically over the toeboard holes and correspond with them. To locate the centers of these holes, the same lines uxzy are drawn on the rackboard as were drawn on the toeboard; at the intersections the holes are drilled with a series of bits and tapered cutters until the pipes fit. Then the rackboard is mounted about a half-foot above the toeboard, on pins at the four corners secured by screws; then the toes of the pipes are inserted in the rackboard holes and the toes in the toeboard, like pipe KH [fig. 14]. Note that the pipe mouths must be above the rackboard, and consequently the feet must be a few inches longer than the distance from rackboard AbCd to toeboard ABC[D] .

The result of this construction is that when the pallet box is filled with wind from the bellows, if the organist depresses a key (which through its tracker will turn a roller in the roller board, which through another tracker will pull a pallet down, opening it), the condensed air in the pallet box will enter the channel whose pallet is open, and go from there to the corresponding hole in the toeboard, whence it will enter the pipe through the toe hole, and make it speak. See the explanation of how wind makes pipes speak in the articles Bourdon 16’ and Stops.

The windchest of the positive is little different from that of the great organ, the only difference being that the pallet box, EF , fig. 12 ,  [12] lies on top of the table, and that the pallets open by lifting from below with short stickers On , resting on the tops of the positive backfalls. See Backfalls of the positive or small organ and Positive.

1. All references to figures in this article are to this plate. (Editor’s note.)

2. A ligne is one-twelfth of a pouce (Translator’s note).

3. The original gives “NLMK” (Translator’s note).

4. References missing (Translator’s note).

5. The original gives “7 and 10.” Fig. 6 shows the lower edge rabbet of the bung board reversed (Translator’s note).

6. “F” (center piece?) is omitted from fig. 7.

7. In fact, a “run” (Translator’s note).

8. The original gives “EC” (Translator’s note).

9. Plates II and III show a single board instead of a separate toeboard for each register (Translator’s note).

10. The plate only shows 12 sliders (Translator’s note).

11. See note 9, which also applies to the rackboard (Translator’s note).

12. Actually, FF (Translator’s note).