R.
Rab.
A stick used in mixing hair with mortar.Rab′at.
A polishing material formed of potter's clay which has failed in baking.Ra-bat′ment.
（Shipbuilding.) The draft of the real shape of the molding edges of pieces of the frame in any required position.
Rab′bet.
1. (Carpentry.) A rectangular groove made longitudinally along the edge of one piece to receive the edge of another. A rebate. It is common in paneling, and in door-frames for the door to shut into.
2. (Shipwrighting.) That part of the keel, stern, and stern-post of a ship which is cut for the plank of the bottom of fit into.
Rab′bet-ed lock.
（Locksmithing.) A kind of lock whose face-plate is sunk within a rabbet cut in the edge of a door.
Rab′bet-ing–ma-chine′.
A machine for forming rabbets. Rabbeting-machines for wood, as well as other kinds of planing and molding machines, were supplied by General Sir Samuel Bentham to the British Admiralty before 1800. Many planingma-chines and all matching and molding (wood) machines may be set to cut rabbets.Rab′bet–joint.
（Carpentry.) A mode of joining wooden stuff in which rabbets are made upon the contacting edges of the boards, so as to overlap each other. See joint.
Rab′bet–plane.
（Joinery.) A plane for plowing a groove on the corner edge of a board. According to their shape, which is such as to adapt them to peculiar kinds of work, they are known as squarerabbet, side-rabbet, skew-rabbet planes. The square-rabbet plane has its cutting edge square across the sole. Skew-rabbet plane; the bit obliquely across the sole. Side-rabbet plane; having the cutter on the side, not the sole.
Rab′bet–saw.
A saw adapted for forming grooves in the edges of plank, etc. That illustrated has an adjustable fence or gage C attached to a handle similar to a planestock, so as to cut at variable distances from the edge. |
| Rabbet-saw. |
Rab′ble.
（Metallurgy.) An iron bar with an end bent at a right angle, used for stirring the molten iron in the puddling or boiling furnace, for removing slag from the surface, and for gathering the metal into loops or balls for the tilt-hammer or squeezer. A mechanical rabble is used in some forms of puddling-furnaces. See page 1815.
Rab′bler.
（Metal.) A scraper.
Ra′bot.
（Marble-working.) A hard-wood rubber used in rubbing marble to prepare it for polishing.
Race.
1. (Hydraulic Engineering.) The canal or course by which water is conducted to a waterwheel from the mill-pond or stream above, and is conveyed away after having done its work. The water reaches the wheel by the head-race and leaves it by the tail-race.
2. (Loom.) The path or guiding trough for the shuttle in the lay or batten.
Race–cloth.
（Menage.) A cloth used in connection with race-saddles; it has pockets to hold the weights needed to meet the requirements of the rules of the race-course.
Race–glass.
（Optics.) A common name for a lorgnette or binocular field-glass.
Race–knife.
A tool with a bent-over, sharp lip for scribing. It is used in laying down on the floor the lines on the body plan, by which the smith bends his bars in forming iron frames for ships. |
| Race-knife. |
Race–sad′dle.
（Menage.) A very small light saddle, used only for racing purposes.
Rach′i-o-tome.
（Surgical.) A post-mortem or dissecting instrument for opening the spinal canal. There are two kinds: one, a saw with double blades, which are caused to approach or recede from each other by means of set screws, making two parallel cuts at once; the other, an axe-like chisel with a round, projecting point, which is inserted into the hollow of the vertebrae and guides the chisel while the operator holds it by the handle with one hand, striking on it with a hammer held in the other hand.
Rac′ing–bit.
（Menage.) A jointed-ring bit, made very light, the loose rings varying in size from 3 to 6 inches.
Rack.
1. (Husbandry.) A frame of open-work to hold hay or other feed for cattle, horses, or sheep. The example is a sheep-rack; has a grain-trough B C pivoted in a drawer beneath the bars of the hay-rack, so that it may be folded and slid in, rendering the arrangement more compact and preventing the animals having access to the food except at stated times. A feed-rack.
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| Sheep-rack. |
2. (Wagon.) A frame to carry hay or grain, placed on a wagon-gears instead of a box-bed, for hauling in the harvest. Sometimes it is laid upon the wagonbed; but this is not so good, as the bed makes the load too high and too short, and adds unnecessary dead-weight.
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| Wood-rack |
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| Rack-movement (lard-press). |
3. (Gearing.) A toothed bar whose pitch-line is straight, or, if curved, embraces but a fraction of the circle and is called a segment-rack, for imparting rectilinear motion, and operated by a toothed pinion or segment or by a pawl. In the example, where it works the piston of a lard-press or sausage-stuffer, the rack H′ is raised or lowered by a pinion, and may be held at any desired hight by a pawl engaging a ratchetwheel on the pinion-shaft.
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| Rack and worm. |
4. (Metallurgy.) An inclined frame or table, open at the foot, and upon which metalliferous slimes are placed and exposed to a stream of water, which washes off the lighter portions. It is to the slimes what buddling is to the ores. The operation is known as racking, recking, and framing in different districts of Cornwall, and particularly applies to tin ores. See frame.
5. (Horology.) A steel piece in the striking part of a clock. It consists of a bar attached radially to an axis, and having a lower and an upper arm. The former is called the rack-tail, and is in contact with the snail on the center arbor, which determines the number of strokes. The upper arm is indented with 12 notches, to act in concert with the hawk's bill in effecting the striking of the right number.
6. (Luce.) A certain length of lace-work, counted perpendicularly, and containing 240 meshes.
7. (Nautical.) a. A frame of wood with belaying-pins, or a row of blocks for fairleaders, or a row of sheaves for reeving the running-rigging. b. A frame with holes for roundshot. c. A box in which the halyards are coiled away.
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| Racking a fall. |
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| Rack-and-pinion jack. |
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| Rack-and-pinion baling-press. |
Rack-and-pinion jack.
A lifting-jack, in which a rack and pinion is employed for gaining power. In the example, a pinion turned by a twoarmed crank engages a gear-wheel fixed on the same shaft with a pinion meshing with the rack. Greater power may be obtained by increasing the number of wheels in the train or the difference of their radii.Rack-and-pin′ion press.
In this the force is transmitted, as the name indicates, through a pinion to a rack which is connected with the follower. In the faster movements of the follower, during the return-stroke, the gearing acts directly on the rackbeam; but during the heaviest compression the gearing operates through a windlass and rope. A sliding pinion d operated by shifting lever n is the means of direct motion of the rack-beam C, when retracting the follower b. |
| Rack-and-pinion propeller. |
Rack-and-pin′ion pro-pel′ler.
In order to obviate the inconveniences attending the use of horse-power and the injurious action of the ordinary paddle-wheel or propeller on the banks of canals, various devices in which wheels actuated by a motor on board the boat engage a continuous rack or rail at or above the canal bank, have been proposed. Fig. 4097 shows one contrivance. A shaft B, driven by the engine, turns a cog-wheel C, connected by an endless chain with the spur-wheel E, on whose shaft is a pinion meshing with a rack J on the canal-bank. The bearings of the shaft B move freely in a vertical direction, so as to correspond with the variable immersion of the boat depending on the amount of her cargo. The boat is maintained in line with the con- [1852] tinuous rack by a roller K having flanges, which hold thereto while passing over the teeth. This also has vertical self-adjustment.Rack-cal′i-pers.
Calipers whose legs are opened and closed by rack-and-pinion motion.Rack-com′pass.
A joiner's compass, with a rack adjustment.Rack′et.
1. A stringed battledore. 2. A snow-shoe. 3. A wooden sole for a man or horse to support the body when treading on soft or swampy ground.Rack′et-wheel.
A wheel toothed to receive a click or pawl. A ratchet-wheel.Rack-hook.
（Horology.) A device in the striking part of a repeating clock, which successively engages the teeth of the rack when the hours are struck. The gathering-piece or pallet.
Rack′ing.
1. (Mining.) Washing impurities from the ore.
2. (Nautical.) Seizing two ropes together by a number of cross-turns. Spun yarn is used for seizing. 3. Decanting wine from the lees in a cask, after fermentation or fining.
Rack′ing-can.
（Metal-working.) A can filled with sour beer, in which wire is steeped before drawing.
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| Racking-cock. |
Rack′ing-cock.
A form of faucet used in the cellar for racking off wines or ale.Rack-rail.
One laid alongside the bearing rails of a railway, and having cogs into which meshes a cogwheel on the locomotive. Blenkinsop's English patent, 1811. This had a toothed rail laid down on one side of the railway, from end to end. A cog-wheel was rigged out from the locomotive so as to engage with the rack and propel the train. It was at that time supposed that the adhesion of the driving-wheels to the track would not be sufficient under ordinary circumstances to enable the locomotive to draw the train. See locomotive, Fig. 2984. Chapman, in 1812, substituted four pairs of drivers connected by gearing, so as to multiply the frictional contact. Snowden, in 1824, had a hollow trunk between the two rails and depressed below the surface. On one side of this trunk was a rack, and the trunk itself had rails traversed by a carriage, which the inventor termed the “mechanical horse.” On the horse was a vertical shaft with a horizontal cog-wheel at its lower end gearing into the rack, and a bevel-wheel above engaged by a similar wheel on the front of the locomotive, and driven by the engine. As the wheel on the locomotive rotated, the upright shaft conveyed motion to the cog-wheel beneath, and this acting on the rack drew along the mechanical horse and the train connected thereto. Easton's English patent, 1825, specifies a central rack, placed between the two rails, and a toothed wheel on the locomotive. Guide-rollers bear laterally against the smooth sides of the central bar, in order to keep the carriages from swerving from the track. The rack-rail is now only to be found in some forms of inclined-plane railways. See also center-rail.Rack-saw.
A saw with wide teeth.Rack-tail.
（Horology.) A bent arm connected with the toothed segment-rack, by which the striking mechanism of a repeating clock is let off. It has a pin on its end, which falls into that one of the 12 notches of a snail on the star-wheel whose depth and position relative to the center of the star-wheel allows the rack to turn a number of teeth corresponding to the hour which is to be struck.
Rad′dle.
1. (Nautical.) Interlacing yarns to make flat gasket.
2. (Weaving.) A bar with upright pegs, used by weavers to keep the threads in place when winding the warp on to the beam. 3. An iron bar with an end bent at right angles, used by puddlers in stirring the iron in the furnace, and also in making up the balls for the tilt or squeezer. A rabble.
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| Radial drilling-machine. |
Ra′di-al Drill′ing-ma-chine′.
An upright machine, designed for drilling a series of holes without changing the position of the work. In Thorne, De Haren & Co.'s, the arm a carrying the drill and its gearing is rotatable on the collar b surrounding the upper part of the fixed post c, on which are the driving-pulleys. The counter-shaft is at the base, and the belt by which they are driven is changed from the loose to the fast pulley and rice versa by the belt-shifter d. The table e is slotted at top and sides, and can be raised or lowered to suit the work, by a pinion working in the rack f and operated by the crank g. The drill may be traversed back and forth on the arm a by a rack and pinion, and is provided with automatic changeable feed-gears; or the feed motion may be controlled by the hand-wheel h through a worm on its shaft, which gears with a worm-wheel whose shaft carries a pinion meshing with the feeding-rack i. See also horizontal lathe; boring-machine; drill. |
| Radial-piston water-wheel. |
Ra′di-al-pis′ton Wa′ter-wheel.
One having floats which are projected from the periphery against the breasting. The wheel receives its water a little past the meridian, where the sliding pistons G H [1853] begin to protrude to receive the force of the water admitted through the gate C, and before the arm becomes vertical; it extends all the way to the inner periphery of an apron which confines all the water behind. The sliding arms have friction-rollers to facilitate their movement, which is directed by an interior arrangement of cams.Ra′di-al Plan′ing-ma-chine′.
（Wood-working.) A machine for chamfering or cornering the edges of timbers. It has a conical cutter, which ordinarily chamfers the edge to an angle of 45°. A pair of such cutters on an axis, at a regulated distance apart, to adapt the machine to given dimensions of timber, will chamfer both edges at one operation.
Ra′di-a′tor.
（Heating.) A chamber or drum in an apartment, heated by steam or hot air and radiating warmth into the apartment. It may be placed above a fireplace, stove, or furnace, and be heated by the volatile products of combustion on their way to the chimney; or it may form a part of a steam circulation, deriving its heat by steam-pipes from a boiler. See heating-apparatus.
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| Stove-drum. |
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| Fireplace-radiator. |
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| Steam-radiator. |
