CHAPTER XIII.BONE DEPARTMENT.

Bone Department — Hard Bone — Glue Bone — Bone Products — Horns — Manufactured Articles — Skulls — Test Yield from Skulls and Feet — Buttocks and Thighs — Blades and Ribs — Drying — Crushed Bone — Grinding Bone — Neats Foot Oil Storage — Neats Foot Oil Purifier — Yield Tests.

—The bone department is where the bones are cared for and prepared for commercial purposes. Nearly all bones that are of value, to be sold as such, come from cattle, and to this department is sent the horns, skulls, jaws, feet, shank bones, thigh bones, blade bones, rib bones and those resulting from cutting and boning cattle. These yield what is known as manufacturing bone, such as shins, blades, buttocks and thigh bones. Most of the balance is used for bone fertilizer, glue and grinding. The bone usually produced in the bone department is hard bone.

—Hard bones are those not cooked sufficiently to extract the glue stock, but enough to remove all grease. They are cooked in open vats. Excessive boiling brings the bones out in what is known to the trade as a “chalky condition” and injures the quality.

—Bones used for glue stock are green bones just as taken from the animal, or dried hard bone. In the former case the bone is crushed green, washed, boiled, and the liquor collected, filtered and evaporated. The residue is dried and is the article of commerce sold under the heading of “Steam Bone,” used extensively in fertilizer manufacturing. Those who slaughter on a moderate scale are usually not in a position to undertake the manufacture of glue. Consequentlythey are most interested in proper methods of manufacturing hard bones.

—Small bones are also converted into bone charcoal, which is largely used for the purpose of bleaching sugar and in various medicinal preparations. Bones are used for a great variety of purposes, including the manufacture of bone charcoal for bleaching, empyreumatic oils; tallow; black pigment for painting, shoe blacking and filling sheet rubber for overshoes; bone dust for manure; sulphate of ammonia; cupels; vitrified bone of use in making opal glass, and in the manufacture of knife-handles, combs, fans, buttons, etc. Bones also furnish gelatine and glue, and are the starting point for the manufacture of phosphorus.

—Horns are the most valuable bone products measured by weight. Owing to the dehorning of cattle as well as the breeding of polled cattle, the supply of horns has been greatly diminished, and whereas twenty-five years ago horns were worth $20.00 a ton they are now worth from $280.00 to $300.00 per ton if they are of the proper selections, hence it will be seen that intelligent handling is worth while. The horns severed from the head preferably by sawing and cutting at a point beyond the meeting point of skull and horn, are thrown into a vat of water, held at a temperature of from 140° to 150° F. After soaking for ten or fifteen minutes they are taken out and by hammering the horn across some solid substance, or by laying it on a block and pounding it with a weight or mallet, the pith slips out. The piths are dried and used in the manufacture of glue. The horns should be stored in a room where there is ample outside air circulation and not too dry. Artificial heat will cause them to crack. They are never dried on steam coils. Selections are made for some markets, although they are usually sold as taken off.

—The manufacture of horns into manufactured articles is a highly specialized work and rarely undertaken by the packer as a commercial possibility. Horns are used for the manufacture of combs and various other ornamental articles. In the course of manufacturing, the tip is sawed off to the hollow part of the horn. It is then split open, the horn is steamed, softened and flattened by pressure, usuallyhydraulic pressure. Any checks or flaws in the horn damage it for manufacturing purposes. If submitted to excessive heat in drying or stored in a room that is hot and dry they are sure to become damaged. When in storage they should be placed in a cellar or room where there is some moisture, but not enough to cause them to mold.

FIG. 60.—CATTLE HEAD SPLITTERS.

—The treatment of skulls in process is as follows: The cheek meat is removed from the head, the jaws pulled out, the head split and brain removed, and the skull is ready for the cooking vat. The brain is an edible product, for which there is a ready sale in most markets, consequently they should be properly taken out. The illustration,Fig. 60, is of a machine with a hollow knife intended for splitting the skull but not damaging the brain. With this machine the heads are split after the jaws are pulled. The head is laid on the table with the teeth up. The knife is made with a semi-circular space in the sharp edge which comes down over the brain without touching same as the balance of the blade isforced through the skull, leaving the brain intact while separating the skull bones. Where a large number of heads are handled in this manner it saves a great deal of labor. It is desirable to remove the brains before cooking the skulls, as the bones become discolored if the brain is left in the skull.

—After the skulls are placed in a tank they should be kept covered with cold water until collected in sufficient quantity for cooking. They should be thoroughly washed, as there is a large amount of clotted blood usually adhering to the skull, and if not well washed the grease derived from the cooking is discolored and injured. In connection with the washing, it is always well, when the vat is filled, to heat the water to a point about 90° F. and draw this water off. The vat is then filled with water sufficient to cover the skull and the steam turned on, the temperature raised to 200° F. The steam should be graduated so as to hold this temperature eight and one-half or nine hours, when the heads will be found to be cooked sufficiently. The steam is then shut off and the oil cooked from the heads is allowed to collect on the surface, after which it is skimmed and strained, and allowed to settle. It is then ready for tiercing.

—The skulls should be kept covered with water until ready for washing. This is done by passing through a reel screen arranged with a central hollow axle or a perforated pipe suspended in the top, used for spraying the revolving bones with a plentiful supply of warm water for cleansing them.

—Jaw bones should be handled the same as skulls, except that they should be cooked from nine to ten hours. The jaws are cracked at right angles to their length in order to open the bone for extracting all oil.

—The bones are now ready for drying. Dryers are mentioned subsequently.

—The cattle feet are of prime importance owing to the value of the products resulting. In mentioning feet, we mean comprehensively the feet from knee to hoof, inclusive.

—The feet upon being taken from the animal should be washed promptly, and all manure and refuse removed preferably through a revolving washer.

—The sinews are removed from the feet, and the shin bones sawed out. The sawing of the bone is an important matter. The bone should be rigidly held and sawed by a sharp moving blade, the saw carriage moved against the tightly held foot. The set of saw should be such as to avoid a ragged edge. Saw should have high speed up to 1,200 r. p. m. and be filed with but little set. In moving the blade it should be done firmly and regularly—not jerky.

The cutting should be done about midway through the “sponge” formation at end of bone so that the oil can be cooked clean.

FIG. 61.—BONE SAW WITH IRON FRAME.

—These bones should be kept in clear cold running water until the day’s cook is collected.

—The removal of hoofs is to be done by putting the feet in a tank or tub of water. Steam is injected into the water and the temperature raised to about 180° F., where it is maintained for 20 to 30 minutes, or until the hoofs will slip. Hoofs are pinched off and feet passed to cook boxes. Hoofs are usually air dried and selected into white and striped hoofs, the most valuable used and sold formanufacturing. Black hoofs are ordinarily coil dried and ground for fertilizer. The oil is the neatsfoot oil of commerce.

—Shin bones should be cooked about eight hours at a temperature of 160° to 170° F.

FIG. 62.—HAND HOOF PULLER.

Judgment is to be used in the cooking as the age of the cattle and the hardness of the bone will have to do with the bone appearing “chalky” when dry.

FIG. 63.—POWER HOOF PULLER.

—The foot portion resulting in the small knuckles when cooked is cooked separately from the shin bones and oil handled in the same manner.

—The oil rising to the top of the cook vats should be carefully skimmed off with as little water as possible. It should be strained through a fine mesh screen covered with two thicknesses of scrim, so as to take out all floating fibre or floaters.

—Upon skimming deposit oil in the oil receivers, keep the oil under heat at a temperature of 150° F. The settling or sediment should be daily removed at the drain outlet until oil begins to show, since the settling and moisture are sure means of making oil sour.

FIG. 64.—REVOLVING BONE WASHER.

—The oil is kept in the containers until ready for purifying. The two receivers are connected together by a common pipe which terminates in a pipe arranged in the form of a cross with a tee connection at each end. Over the ends of this cross are suspended cotton flannel bags of double thickness tied tightly over the tees. The oil is strained through these into the purifier where it is settled for two or three hours. Should any moisture appear it is withdrawn at the drain cock at bottom. Bags should be used once and carefully washed. The oil is then dried out by heating the same through the steam jacket on kettle until it reaches a temperature of about 250° F., at which temperature it is held several hours. The oil is to be stirred occasionally during the drying period. The steam is closed and the oil allowed to settle andcool and is then put in casks. Temperature of oil when drawn into casks, about 80° to 90° F., casks, hard wood, well hooped and of superior quality to prevent leakage.

—Obtained from cooking round shin, flat shin, small knuckle bones (being bones from feet) and shin bones.

—After taking the oil and depositing same in the neatsfoot oil receiver, the shin bones are removed and placed in the polisher where they are revolved for about one hour or until the bones are cleaned. Warmed water is passed through the bones during this process, introduced through hollow shaft in washer. The substance washed out contains more or less oil which should be trapped and the clear oil skimmed off, and balance of material sent to the rendering tanks. The knuckles are similarly treated until cleaned.

—When the shin bones are washed and cleaned they should be spread on racks to dry, in natural temperature (not coil dried) and out of draft or cold temperatures to avoid checking or splitting. Small knuckle bones from the feet are to be coil dried for manufacturing bone.

—These are chiefly sold for glue stock. In removing sinews from the legs, care must be used not to cut too deep in the heel of the foot, it being preferred to leave some glue stock on the foot rather than to cut too deep and remove the fat which goes to make up the neatsfoot oil which is much more valuable than the glue stock. This part of the product, well drained, should be taken to a cool, although not necessarily refrigerated room, and thoroughly salted; It is often found necessary to overhaul it and resalt it in order to keep it from “sweating.” After it has been cured ten days or two weeks it is ready for the glue department.

—Test onfollowing pageshows the yield from head and feet of 130,470 cattle, same based on the market prices prevailing at the time the test was made. While prices vary the percentages given are accurate.

—These leg bones are treated substantially the same as the shin bones in cooking and to completion.

AVERAGE YIELD OF HEAD AND FEET ON KILL OF 130,470 CATTLE.

—Where cutting and shipping cattle is done in profusion there are many small bones resulting. If hard bone is being made these bones are cooked in open vat from six to eight hours. Cellular bones are usually cracked so as to make for free extraction of oil.

—Two systems of drying are used in the bone department. The open air system for horns, selected white and striped hoof for manufacturing, shin bones, buttock bones, and those sold for manufacturing purposes; the coil, or room, drying principle, for grinding bone. The latter, crushed bone, is sold to glue makers and grinders. The usual method of handling the latter style of drying is to make platform coils or grids of 1¹⁄₄-inch pipe of an area convenient, as ten by sixteen feet, or units convenient to the space. These are in multiple and arranged to be accessible from two or more sides for convenience in filling and removing bones. The grids should be placed twelve or fifteen inches above the floor to permit cleaning underneath. The pipes or grids are usually substantially supported to carry the weight placed upon them. A wire screen of No. 5 screen 1¹⁄₄-inch mesh is a convenience to prevent bones dropping through. The bones are piled upon thegrids to dry, when they are then transferred to storage rooms.

—The skulls, jaws and larger bones, are usually crushed before storing so as to get a greater weight in less space. In this condition they are ready for grinding into “raw bone meal,” the name given to ground bone for sale to glue makers for extracting glue.

—Ground bone is usually ground through an attrition mill, of which there are several types. The mill delivers the grindings to a bucket type endless chain elevator, which in turn passes it through a screen—shaking or revolving—preferably the latter. The screen is usually about three feet in diameter by twelve feet long and covered with a screening of No. 16 wire, eight meshes per inch, which screens it to a size that will readily pass through a grain drill. The tailings or over sized bone is returned to the mill for further grinding.

—This is preferably a jacketed tank, one tank within the other, and must be made with a jacket to withstand the pressure that may be applied. Consequently the jacket should be reinforced with stay bolts so as to prevent distortion when pressure is applied. Any and all oil settling vats are best made cylindrical in form with a sharp cone at bottom. The cone is equipped for withdrawing sediment at the bottom and for withdrawing oil for purification sufficiently high in the cone to avoid withdrawing any sediment.

—The same type of kettle or tank as described above is required, the latter being sufficient in size to accumulate a week’s work.

—The appended tests give the resulting yields from handling skulls and jaws, feet and shanks:

TEST YIELD FROM SKULLS AND JAWS OF 1,209 CATTLE

Total weight of feet from 1,209 cattle, 20,790.11 pounds. Average weight green feet per cattle, 17.19 pounds.

TEST YIELD FROM FEET OF 1,391 HEAVY CATTLE

Total weight of feet from 1,391 cattle, 24,778 pounds. Average weight green feet per cattle, 17.8 pounds.

TEST YIELD IN FINISHED PRODUCTS FROM SHANKS

Weight 3,300 pounds each, fore and hind shanks, total 6,600 pounds.

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