LATHE DOGS The steady rest provides a fixed support between head and tailstock for long, round work while it is being turned. The support this rests gives a shaft of small diameter, for example, permits use of a coarser feed, and prevents chatter and any tendency for the work to spring away from the tool. Many jobs are impractical without the use of the steady rest. CHASING DIAL Lathe dogs (96) are used with the small face plate to grip and to drive pieces between centers. Dogs of different sizes can be obtained for use with corres- ponding diameter of work. The usual form of lathe dog has a bent tail which engages a slot in the face plate.
Another form is known as the clamp dog (97) and is used to drive square, hexagon or octagon shaped pieces between centers. FOLLOW REST The chasing dial, or thread indicator, comprises a worm wheel which meshes with the leadscrew and a shaft connecting the worm with the numbered indicator dial. When chasing an even number of threads, the halfnut may be engaged .at any line on the dial; for odd threads, at any numbered line; and at any odd numbered line for half-threads.
Using the chasing dial in this manner, the operator can take a cut, back the tool out of cut and return the carriage to the starting position, set the tool for the next depth of cut, and re-engage the half-nut without stopping or reversing the lathe spindle. TELESCOPIC TAPER ATTACHMENT The follow rest is used to support between-centers work against the forces of the cut being taken. It is bolted to the carriage and consequently moves with it. To set the follow rest, the cut is started and turned slightly longer than the width of the follow rest jaws. The jaws are then set to the turned diameter after which the cut can be taken across the entire length of the piece of work. STEADY REST FIG.
25 – TELESCOPIC TAPER ATTACHMENT The telescopic taper attachment is ruggedly con- structed and simple to operate. When the carriage is brought into position for the taper operation, the bed bracket (1) is tightened on the flat bed way. The swivel guide bar (2) is adjusted to the selected taper, which is marked in inches on one end of the lower bar and in degrees on the other end of the bar. Adjustment for selected taper is made by loosening nuts (3) and moving bar (2) to the desired taper. The swivel guide bar is held secure by the screws (3). With the taper bar ] FIG. 23 – STANDARD AND OVERSIZE STEADY RESTS 17