Emery wheel

“ When a single emery-wheel is used there is evidently twice the amount of wear to take a given amount of metal off (per traverse) that there is when two wheels are used, and furthermore the reduction of every wheel diameter per traverse is evidently twice as great with one wheel as it is with two. ”

“ In some cases the work may remain stationary and the emery wheel only rotate. Thus, suppose it was required to grind the necessary clearance to relieve the cutting edge c of the reamer, then a could be rotated until c stood in the required position with relation to b, and the revolving emery wheel may either be traversed along, or the work may traverse past the wheel, according to the design of the grinding lathe, but in either case a remains stationary during each cut traverse; after each successive traverse a may be rotated sufficiently to give a cut for the next traverse. ”

“ Emery, corundum, carborundum, and other artificial abrasive wheels have in many cases supplanted the grindstone, as they cut much more rapidly. Any one not accustomed to using them must be careful that the temper of the tool is not destroyed, as the wheel runs at a high rate of speed, and a tool in unskillful hands is easily burned. To avoid this, the tool should be held lightly but firmly against the stone, and frequently dipped in water to cool it. If an emery wheel burns badly, it may be because it needs dressing ”

“ The heat that has been developed is the measure of the mechanical energy that I have used against the emery-wheel. Now, let us substitute for the emery-wheel another wheel of the same size made of vulcanized rubber, glass or resin. I set it to revolving at the same speed, and instead of the piece of steel, I now hold a silk handkerchief or a catskin against the wheel with the [Pg 45] same force that I did the steel. ”

“ Such a material must bind the emery together with sufficient strength to withstand the centrifugal force due to the high speeds at which these wheels must be run to work economically; and it must neither soften by heat nor become brittle by cold. It must not be so hard as to project above the surface of the wheel; or in other words, it should wear away about as fast as does the emery. ”

“ When the high side of the roll meets the right-hand emery wheel it will bear against it, causing the swing-frame to move to the right, and the pressure between the wheel and the roll will again cause the high side of the latter to be reduced by grinding. This action will continue so long as the roll runs out of true, but when it runs true both emery wheels will operate, grinding it to a diameter equal to the distance between the emery-wheel perimeters, which are, of course, adjusted by the slide rests a a. ”

“ The higher rate of speed, which not only cuts faster, but, in the case of the vulcanite emery wheel, prolongs the life of the wheel, is concededly safe with the vulcanite wheel. Thus run, it is not likely to wear out of true, the operator does not have to bear on so hard, and the wheel retains its shape much better than when run at a slow speed. ”

“ These difficulties occur more with emery-wheels than with grindstones, either because emery-wheels glaze more easily than grindstones, or because, owing to their superior cutting powers under any circumstances, they are more neglected than grindstones.
Experience shows that these bad results occur almost invariably on glazed wheels. It is rare to find any bad work come off from a clean, sharp wheel, unless the pressure has been so excessive as to show that the operator is either foolish or stupid. ”

“ Fig. 2035 represents an emery planing machine. The emery wheel, which takes the place of the cutting tool of an ordinary shaping machine, is upon a spindle driven by the pulley a upon the spindle b, which is traversed endways by means of the connecting rod which is actuated by a crank e driven by the cone pulley c. The work-holding table g is traversed by the handle k or automatically through wheel h, which through suitable gearing drives the spindle i. The blower or fan is to draw off the cuttings and emery. It is obvious that any of the usual forms of work-holding devices may be employed. ”

“ An emery wheel plays a very important part in a commercial welding shop, insomuch that rust, scale, and unnecessary metal can be removed in a very short time by its use. A flexible shaft attachment should be on hand, if possible, or a portable grinder of some kind, for in many cases where the casting, or the piece being worked upon is too heavy to bring to the emery wheel, the wheel can be brought to it and many places ground down by its use that would be impossible with a stationary grinder. ”

“ Speeds for Emery Wheels.—The speed at which an emery wheel may be run without danger of bursting varies according to the thickness or breadth of face of the wheel, as well as according to the quality of the cementing material and excellence of manufacture. ”

“ Pressure is injurious not so much to the wheel as to the tool itself. The moment a tool becomes heated there is danger of destroying the temper, and the edge, being the thinnest, is the most violently affected. Hence it is desirable always to have a receptacle with water handy, into which the tool can be plunged, during the process of grinding down.
Correct Use of Grinder.—Treat the wheel asp. 28 though it is a friend, and not an enemy. Take advantage of its entire surface. Whenever you go into a machine shop, look at the emery wheel. ”

“ As this wheel is a driver, a smaller wheel will make the emery roller move slower, and therefore more picks will be put in the cloth, and a larger wheel will drive the emery roller quicker, and as a consequence a smaller number of picks will be put in. ”

“ The finest of emery applied upon such wheels is used for cast iron, wrought iron, and steel, to give to the work a good ordinary machine finish; but if a high polish or glaze is required, the wheels are coated with flour emery, and the wheel is made into a glaze-wheel by wearing the emery down until it gets glazed, applying occasionally a little grease to the surface of the wheel. ”

“ It is sometimes practicable to use wheels of a certain diameter upon machines speeded to suit that diameter, and to transfer them to faster speeded machines as they diminish in diameter. Even by this plan, however, only an approximation to a uniform speed can in most cases be obtained, because as a rule certain machines are adapted to certain work, and the breadth of face and form of the edge of the emery wheel are very often made to suit that particular work. ”

“ It is obvious that in a lathe of this kind, there must be an extra overhead shaft, driving a drum of a length equal to the full traverse of the lathe carriage, or of the plate carrying the head and tailstocks, and the arrangement of this drum with its belt connection to the pulley on the emery wheel arbor, is sufficiently shown in figure. To protect the ways of the bed from the abrasion that would be caused by the emery and water falling upon them, guards are attached to the carriage extending for some distance over the raised Vs. ”

“ The nature of the wear of the working surface in the vulcanite wheel is claimed to be essentially different from that in wheels where the emery is fixed in its place by other methods, the rubber affording an elastic foundation or cushion, from which the particles of emery slightly protrude. ”

“ With the same grade of emery the wheel will cut more freely and glaze less in proportion as the cementing material leaves the wheel softer, but the softer the wheel the more rapidly it will wear away; indeed it is the dislodgement of the emery points as soon as they have become dulled that produces freedom from glazing. ”

“ For instance, vulcanite emery wheels 18 inches in diameter and having 3⁄16 inch thickness, or face as it is commonly termed, are not unfrequently used at a speed of some 5,000 feet of circumferential feet per minute, whereas it would be altogether impracticable to use a grindstone of such size and shape, because the side pressure would break it, no matter at what speed it were run. ”

“ Indeed, in the superior strength of the emery wheels of the smaller sizes lies their main advantage, because they can be made to suit narrow curvatures, sweeps, recesses, &c., and run at any requisite speed under 5,000 feet per minute, and with considerable pressure upon either their circumferential or radial faces. ”

“ They are strong and safe at the highest speed at which it is desirable to run them, the company recommending that they never be run at a less rate than 6,000 feet per minute circumferential speed, and from that up to 8,000 and 10,000 feet per minute, although the lowest named speed is rather above the ordinary limit of many other kinds of emery wheels, and attempts to run other wheels at or beyond this limit have frequently resulted in serious accidents, from the breaking of the wheels. ”

“ If Bonneville took a wagon across, he could. "I know we can do it—I can almost see a road," said the dauntless doctor, with that positive assurance that always won half his battles.
"Go ahead, then," laughed the traders. "A good wheel route to Green River will double our profits. We will gladly send a man with you to help explore a way."
With the doctor's wagon and a trader's cart the little company pushed on, leaving Fort Laramie, the last outpost of civilized man, on the foothills at their rear. Dr. Whitman made a wagon route his special object of study. ”

“ The perch, axle-trees, and carriage timbers have been reduced to thin sticks. The four wheels are made so slender as to resemble a spider’s web; in their construction of the wheels the principle of the patent rim used in England in 1790 has been adopted. Instead of five, six, or seven felloes to each wheel, there are only two, of oak or hickory wood, bent to the shape by steam. The ironwork of the American buggy is very slender, yet composed of many pieces, and, in order to reduce the cost, these pieces of iron are mostly cast, not forged, of a sort of iron less brittle than our cast iron.... ”

“ The sense of proportion between parts is sadly outraged by spindle-wire wheels supporting the massive frame-work and body of an automobile; however strong they may be in reality, architecturally they are quite unfit, and no doubt the wooden wheel will come more and more into general use.
A wooden wheel with the best of hickory spokes possesses an elasticity entirely foreign to the rigid wire wheel, but good hickory wheels are rare; paint hides a multitude of sins when spread over wood; and inferior wooden wheels are not at all to be relied upon. ”

“ The wheels themselves cannot be made by the young experimenter unless he has a lathe. They are flanged wheels, one and one-eighth inches in diameter, and are turned from cast iron or brass. Such wheels can be purchased ready made, or it may be possible to obtain from some broken toy a set which will prove suitable.
Fig. 265.—Details of the Bearing which supports the Wheel and Axle. Each shaft is composed of two pieces of "Bessemer" rod held together by a short piece of fiber rod having a hole in each end into which one end of each piece of iron rod is driven. ”

“ Scarcely any kind of machinery can be constructed without wheels of some kind—they serve almost numberless purposes. The fly-wheel (fig. 1) serves to produce a continuous motion, from its size and weight giving it a tendency to go on, and in this way causing it to fill up the intervals of unequal action, as in the ascent and descent of the piston in a steam-engine. The toothed-wheel serves to give motion to other wheels, and this at a certain rate either greater or less than its own, according to its size, and consequently the number of its teeth ”

“ Pressing this invention to the ultimate produced a spoked wheel. The Egyptians used a six-spoked chariot wheel thousands of years before Ezekiel's time, and the Greeks and others had four-spoke models. This was quite an invention and in addition to its useful aspects, it produced some rather unusual, even magical side-effects. As every child knows, if you turn your tricycle upside-down and spin the wheel, the spokes seem to vanish. All that can be seen is the rim and the parts of the hub near the center of rotation. No matter what shape the hub actually is, it too looks round like a wheel. ”

“ And some are fifth wheels like myself—neither old nor self-effacing, neither middle-aged nor useful, but simply expensive to keep painted, and very hungry for the road. It may be only a matter of time, however, when I shall be middle-aged and useful, and later old and self-effacing; when I shall stay and take care of the children, and go upstairs early when the young people are having a party.
A young technical college graduate told me once, to comfort me, I suppose, that a fifth wheel is considered by a carriage-maker a very important part of a wagon. ”

“ It appears to us that, it being seen that the tendency to reverse would prove objectionable in the proposed machine, the suggestion that the hand-wheels should be made heavier in order, by greater momentum, to correct that tendency, as it was well known increase in weight, coupled with adequate rotative force, would, sprang naturally from the expected skill of the maker's calling, and that this use of the heavier wheel did not make the mechanism in any proper sense a new thing evolved by the inventive faculty. ”