LATHE OPERATIONS - OD1645 - LESSON 1/TASK 1
(a) The compound rest swivel (2) can be swung around to any desired
angle and clamped in position. It is graduated over an arc of 900 on each
side of its center position for ease in setting it to the desired angle.
This feature is used in machining short, steep tapers such as the angle on
beveled gears, valve disks, and lathe centers.
(b) The compound rest top or top slide (3), is mounted on the swivel
section (2) on a dovetailed side.
It is moved along the slide by the
compound rest feed screw turning in the nut (4), operated by the handle (5),
in a manner similar to the crossfeed described in paragraph (5)(b) beginning
on page 12.
This provides for feeding at any angle (determined by the
angular setting of the swivel section), while the cross-slide feed provides
only for feeding at right angles to the axis of the lathe. The graduated
collar on the compound rest feed screw reads in thousandths of an inch for
fine adjustment in regulating the depth of cut.
(11) Toolposts.
(a) Three popular types of toolposts are the standard, castle, and the
quick change.
The sole purpose of the toolpost is to provide a rigid
support for the toolholder.
(b) The standard toolpost is mounted in the T-slot of the compound rest
top as shown in figure 8. A forged tool or a toolholder (13) is inserted in
the toolpost and rests on the toolpost wedge (11) and the toolpost ring
(12).
By tightening the setscrew, with the tool placed in the desired
position, the whole unit can be clamped in place.
(12) Cutting Toolholders.
(a) General. Common cutter bits are generally made from standard sizes
of bar stock to fit into a forged cutting toolholder at an approximate 150
positive rake angle.
The toolholder is fastened to the toolpost of the
lathe.
Special tools such as the knurling tool and the thread cutting
toolholder are furnished with their own special forged toolholder and,
therefore, may be fastened directly to the toolpost of the lathe. Carbide-
tipped cutter bits are generally unsuitable for mounting in forged
toolholders. They are fastened directly
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