Grinding wheel

“ 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. ”

“ The grinding angle.
The Grinder.—The first mistake the novice will make, is to use the tool on the grinder as though it were necessary to grind it down with a few turns of the wheel. Haste is not conducive to proper sharpening. As the wheel is of emery, corundum or other quickly cutting material, and is always run at a high rate of speed, a great heat is evolved, which is materially increased by pressure. ”

“ They are tempered down to a purple or blue colour. In this state they are taken to the grinder.
Grinding and polishing of cutlery.—The various processes which come under this denomination are performed by machinery, moving in general by the power of the steam-engine or water-wheel.
Grinding wheels or grinding mills are divided into a number of separate rooms; every room contains six places called troughs; each trough consists of a convenience for running a grindstone and a polisher at the same time, which is generally occupied by a man and a boy. ”

“ The grinding wheel spindle is carried in a bearing carried in a vertical slide, and is fed to its depth of cut by means of the vertical feed screw and hand wheel shown. The spindle passes through the bearing and carries a pulley at the back of the machine, which pulley is driven by a belt passing over idler pulleys at the back of the machine, by means of which the tension of the driving belt may be regulated. ”

“ The cylindrical grinder was first made as a crude grinding lathe in the early sixties, and used for grinding the needle and foot bars of the Wilcox & Gibbs sewing [214] machines. In 1864 and 1865 the regular manufacture of grinding lathes was begun by using parts of 14-inch Putnam lathes modified to produce the automatic grinding lathes. These modifications consisted in mounting a grinding wheel on the carriage, providing an automatic feeding and reversing attachment, and included the use of a dead center pulley. ”

“ Beyond removing the sharp edges no fitters’ work is required, and the bars go straight to the erecting shop. The type of grinding machine used is quite different from that employed for grinding piston rods, and may be likened to a planing machine, in which cutting tools are replaced by an abrasive wheel. ”

“ After this the gears, being held firmly to their chucks by means of a yoke, were bored rapidly and always with absolute truth. Result: their running was practically noiseless.
Mr. Freeland taught me the secret of producing true cylindrical surfaces by grinding with a wheel. It was to let the swiftly revolving wheel traverse the surface as it rotated, touching only the highest points, and these very lightly. This avoided the danger of errors from the springing of either the piece or the wheel, which under strong pressure is sure to take place to some extent, even in the best grinding-machines. ”

“ This grinding is continued until the edges of stop B and carriage C will remain in contact during a complete revolution of the wheel blank. During this grinding process, the carriage should be moved back and forth from the edge to the center of the grinding disc so that the wear on the abrasive material may be equalized.
Fig. 25. Smoothing the side of wheels
Fig. 26. Using dividers to mark for cuts
A similar device used for chamfering the edges of the blanks is also shown in Fig. ”

“ As the sides of the wheel are flat, however, it is self-suggestive to apply the work to the side faces. But in this case, also, that part of the wheel surface that performs grinding duty will gradually wear away, leaving a shoulder or projecting surface upon the wheel. ”

“ The clearance is, however, reduced and the lip angle changed.
There is great danger when grinding a tool of burning it or drawing the temper from the fine cutting edge, and, aside from the actual shape of the cutting end, this is the most important point in connection with tool grinding. If a tool is pressed hard against an emery or other abrasive wheel, even though the latter has a copious supply of water, the temper will sometimes be drawn. ”

“ Referring to the question of grinding tools, nothing has yet been found so good for high-speed steels as the wet sandstone, and the tools ground thereon by hand pressure, but where it is desired to use emery wheels it is better to roughly grind the tools to shape on a dry emery wheel or dry stone before hardening. ”

“ 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. ”

“ When a flat has passed under the grinding roller completely the rotation of the wheel K causes one of the teeth to push the lever L forward, and so oscillate the shaft upon which the lever B is fastened. ”

“ Different angles of one cutting edge of the drill to the other are obtained by swivelling the frame carrying the shaft of lever f. The emery wheel is cased in except at a small opening where it operates upon the drill, and may, therefore, be liberally supplied with water without the latter splashing over. Water is continuously supplied to the emery wheel by an endless belt pump, which also delivers water on the end of the drill, enabling heavy grinding cuts to be taken without danger of softening the drill at the cutting edge, which is otherwise apt to occur. ”

“ After the tailstock center is withdrawn, the emery wheel is adjusted for grinding. As the wheel spindle is 30 degrees from the axis of the lathe spindle, the lathe center is not only ground true but to an included angle of 60 degrees, which is the standard angle for lathe centers. There are many other styles of center grinders on the market, some of which are driven by a small belt from the cone-pulley and others by electric motors which are connected with ordinary lighting circuits. The tailstock center is ground by inserting it in the spindle in place of the headstock center. ”

“ In the absence of a proper grinding lathe, an ordinary lathe is sometimes improvised for grinding purposes, by attaching to the slide rest a simple frame and emery wheel arbor with pulley attached as in Fig. 678, in which a is the emery wheel, c the pulley for driving the arbor, and b the frame, d being a lug for a bolt hole to hold the frame to the lathe rest. ”

“ In other drill grinding machines the drill when rotated to grind the clearance is moved on the axis a a in Fig. 2022 as a centre of motion, and as this line is parallel to the face of the emery wheel it follows that if the drill were given a full revolution its circumference would be ground to a cylinder as shown in Fig. ”

“ A grinder, shown in Fig. 87, is used for grinding off rough parts of iron or brass castings and for smoothing up rough surfaces. It is formed of a mandrel which turns freely in a pair of bearings set in a headstock. A pulley is fixed to the middle of the mandrel and the latter is threaded on the ends; an emery, or a carborundum wheel is slipped over each end and these are held in place by washers and nuts. A swivel hand rest makes it easy to hold the work against the wheel.
Fig. 87. A GRINDER AND POLISHER
A plain lathe, see Fig. ”

“ This is another admirable engine for diminishing and simplifying human labor. It is applied to the boring of all kinds of iron-work for machinery.
The perpendicular drill, as will be readily observed, is worked with a swift, rotatory movement, by means of the bevil gears at its upper extremity. By a wheel—the circumference of which only is displayed in the cut—acting upon the thread of a screw midway its length, it is pressed down upon the piece of work to be drilled. ”

“ The flint-like grains from the desert blow over the rails, and as the cars move they grind out the steel as though they were emery powder. Consequently, the life of a wheel is short, and we have to cut down its tire every few months. Moreover, the sand gets into the bearings, and there is a continual wearing which necessitates almost constant repair. ”

“ It is a spirited sight to watch the operation of sharpening tools upon a grindstone or emery wheel run by steam. Showers of sparks are produced by the friction. We often observe the same phenomenon when the brakes are applied to rapidly revolving car wheels. ”

“ Once you get a wheel in operation with a shaft and pulley attached, it is then a simple matter to harness your power and make it do all sorts of things, such as sawing wood, churning milk, operating a fan on hot days, and even turning a grindstone or light wood-working machinery. ”

“ A A, fig. 759., is the fly-wheel of an ordinary lathe, round which the endless cord B B passes, and embraces the pulley C, mounted upon the axle of the grindstone D. The flywheel is supported by a strong frame E E, and may be turned by a winch-handle, as usual, or by mechanical power. In the needle factories, the pointing-shops are in general very large, and contain several grindstones running on the same long horizontal shaft, placed near the floor of the apartment, and driven by water or steam power. ”

“ The various parts of the wheels are produced in quantity either by rolling or by dies under the hammer; these parts are brought together in their relative positions in a mould, heated to a welding heat, and then by a blow of the steam hammer, furnished with dies, are stamped into a complete and all but finished wheel. It is evident that wherever wrought-iron articles of a manageable size have to be produced in considerable quantities, the same process may be adopted, and the saving effected by the substitution of this for the ordinary forging process will doubtless ere long prove incalculable. ”

“ But the practical men engaged in the work say differently. It is their maxim that the more iron is hammered, the stronger and better it becomes; therefore all this welding adds to the strength of the wheel. In practice it is found quicker and more convenient to thus divide the labour than to endeavour to form the wheel of fewer component parts. The wheel is now taken to the lathe, and a portion is cut away from its edge, till a groove is left so as to dovetail into the tyre. ”

“ A little grit mixed in with the oil and the balls of the bearings is quite enough to wear the bearings themselves as well as the balls, and in a short time render the wheel practically useless, unless an entirely new set of bearings is put in. Even if you have not been in the country, the fact that you have used the wheel a little each day, and only wiped off the outside of the machine and reoiled the bearings occasionally, is enough to prove that the machine should be taken apart before you begin the fall and winter season. ”

“ A Machine for cutting the Key-Grooves in Metal Wheels and Belt Pulleys, of ANY Diameter.
The fastening of wheels and belt pulleys to shafts, so as to enable them to transmit rotary motion, is one of the most frequently-recurring processes in the construction of machinery. This is best effected by driving a slightly tapered iron or steel wedge, or "key" as it is technically termed, into a corresponding recess, or flat part of the shaft, so that the wheel and shaft thus become in effect one solid structure. ”

“ This machine is, doubtless, susceptible of many improvements, especially in the size and construction of the wheel. By frequent use, the part to which the greatest pressure is applied, will necessarily wear away, and thus injure the drag: to prevent this accident, it ought to be shod, at first, with a plate of iron, or steel, fixed by means of two holes in its bottom ”

“ However, drawing an object on wheels is a decided improvement over sliding it along the road, for two reasons: the sliding friction at the axle is reduced to a minimum by choosing materials that will slide upon each other with comparatively little resistance, by polishing them smooth and by lubricating them. But even if these precautions were not taken there would be a distinct advantage in the use of wheels because of the relatively shorter travel at the axle than at the rim of the wheel. ”

“ The action of long rigid wheel-base vehicles passing [Pg 54] round sharp curves is detrimental to all the parts brought into contact. Not only is there the constant tendency to mount the rails, and spread the gauge, but the tiny shreds of steel scattered all along close to the rail—particles ground off the rails, or off the wheel-tyres, or both—testify to useless wear, unnecessary friction, and great waste of motive-power. ”

“ The rims of the hand-wheels are made sufficiently heavy to act as a balance against the weight of the blade-lifting devices, so that the momentum of the wheel will greatly assist the operator in the manipulation of the machine. ”

“ Each step corresponds to our many-sided wheel falling on to a flat side—and the "hammer, hammer, hammer on the hard high road" is the horsey counterpart of the metallic rattle.
On rough ground a horse has a great advantage over a wheeled tractor, because it can put its feet down on the top of objects of different elevations, and still pull. A wheel cannot do this, and, as we have seen, a loss of power results. Our inventor, therefore, created in his pedrail a compromise between the railway smoothness and ease of running and the selective and accommodating powers of a quadruped. ”