Fig. 808.
[Fig. 808] represents a form of steady rest designed by Wm. MacFaul, of the Freeland Tool Works, for taper work. The frame affords journal bearing to a ring a, having four projections b, to which are a close but easy sliding fit, the steadying jaws c. These are held to the work or cue blank w by the spiral springs shown in the projections or sockets b, which act against the ends of c. It will be observed that the work being square could not move in any direction without moving sideways the two of the steadying jaws c which stand at a right angle to that direction. But the jaws c fit the bore of the sockets, and cannot, therefore, move sideways; hence it is evident that the work is firmly supported, although the steadying jaws are capable of expanding or contracting to follow the taper of the blank cue or other piece of work. This enables the steady rest to lead the cutting tool instead of following it, so that the work is steadied on both sides of the tool. Obviously, the stand may be fastened to the leading side of the lathe carriage or fitted upon the cross-slide, as may be most convenient.
Fig. 809.
To steady work that is unturned and of so great a length that it springs too much to permit of its being turned true, the sleeve or cat head shown in [Fig. 809] is employed; it may contain three or four screws c, to true it upon the work. The body b is turned true.
The set-screws are so adjusted upon the work, that the outside runs quite true from end to end. The jaws of the steady rest are then set to just touch the circumference of the sleeve, care being taken that their pressure does not spring the axial line of the work out of its normal straight line. If the shaft is to be turned from end to end, the cat head should be placed sufficiently to one side of the centre of the length of the work and nearer the live centre, that the lathe tool may turn up the work for a distance of at least half its length, or slightly more than half. One half of the work being turned, the shaft is reversed end for end in the lathe, when the cat head may be moved to envelop the turned part, and again set true, or the jaws of the steady rest may be set direct upon the work; in this latter case, however, the friction between the jaws and the work will be apt to leave rings or marks upon the latter.
If the cat head is not set to run quite true upon the work, the latter will not run true when the steady rest is removed, and if the jaws of the steady rest spring the axial line of the work out of its normal straightness, the work will be turned either larger or smaller in diameter in the middle of its length, according to the direction in which the work is sprung.