The ring revolves with the work and has journal bearing in the stand, the enlarged diameter c preventing end motion. There is nothing here to take up the lost motion that would in time ensue from the wear of the radial faces of the ring, hence it is better to use the cone-plate shown in [Fig. 805].
Fig. 804.
When, however, the work will admit of being sufficiently reduced in diameter, it may be turned down, leaving a face f in [Fig. 804], that may bear against the radial faces of the jaws of the steady rest; or a collar may be set upon the work as in [Fig. 804] at c. But these are merely makeshifts involving extra labor and not producing the best of results, because the radial face is difficult to keep properly lubricated, and the work is apt to become loose on the live centre.
Fig. 805.
For these reasons the cone plate shown in [Fig. 805] is employed; a is a standard fitting the shears or bed of the lathe and carrying the circular plate c by means of the stud b, which is fitted so as to just clamp the plate c firmly to the frame a when the nut of b is screwed firmly home with a wrench.
The plate c contains a number of conical holes, 1, 2, 3, &c., (as shown in section at d) of various diameters to suit varying diameters of work.