[Fig. 2033] represents The Tanite Co.’s machine for surface grinding such work as locomotive guide bars. The emery wheel n is mounted beneath a table t, whose upper surface is planed true, and which has two cylindrical stems c d fitting into the bored guides e. The stems are threaded at their lower ends to receive a screw, on the lower end of which is a bevel-gear f meshing into a similar gear g on the shaft actuated by the hand wheel w, hence by operating w the height of the table face may be adjusted to suit the diameter of the wheel.
The surface to be ground is laid upon the face of the table, and the operator moves it by hand, slowly passing it over the emery wheel, which projects slightly through the opening shown through the centre of the table. The operator stands at the end of the machine so as to be within reach of the wheel, and the direction of rotation is towards him, so that the work requires to be pushed to the cut and is not liable to be pulled too quickly across the table by the emery wheel.
Fig. 2034.
[Fig. 2034] represents an emery grinding machine for grinding the bores of railroad car axle-boxes. The circumference of the emery wheel is dressed to the curvature of the box bore by a diamond tool a which swings on a centre in its frame, and can be adjusted to any arc. Once set, it can only turn the prescribed arc with accuracy. In order to avoid the necessity of the foreman having to set the tool, a gauge is also furnished. This consists of a spindle adjustable with a nut in such a way that its two points rest in the centres on which the diamond tool revolves. It is only necessary for a disk b turned accurately to the diameter of the bearing, to be prepared, and this the apprentice can place on the spindle, adjust the latter, and screw down the diamond tool until it touches the periphery of the disk. A nut is then fastened on the diamond tool, and the frame is lifted on the ways beneath the wheel, when the moving of the handle turns the face of the wheel to the exact circle desired.
To adjust the brass in the chuck c, it is first set on the axle d. The chuck is then placed on frame e, in such a way that the Vs fit. Handle f then moves a cam that clamps the brass between the jaws g, one set of which swings on a pivot at h. The brass is thus adjusted in such a manner that, despite the imperfections in moulding, it is ground accurately with the least removal of metal. The chuck c fits into planed guides on the table i, and is thus brought in exact line with the motion of the wheel. The crank j serves to move the table to and fro on the rods k, and the table also rises and falls on planed ways, being pressed up by springs. The hand wheel gives vertical adjustment to the whole bed by means of a chain beneath it. There is a pulley by which a suction fan, to remove dust, &c., may be driven. The machine is capable of fitting from 150 to 500 car brasses per day.
