LATHE OPERATIONS - OD1645 - LESSON 1/TASK 1
three or four jaws.
The jaws can be moved in unison on a scroll for
automatic centering or can be moved individually if desired by separate
adjusting screws.
(5) Drill Chuck.
The drill chuck is a small universal-type chuck which
can be used in either the headstock spindle or in the tailstock for holding
straight-shank drills, reamers, taps, or small-diameter workpieces.
The
drill chuck has three or four hardened steel jaws which are moved together
or apart by adjusting a tapered sleeve within which they are contained. The
drill chuck is capable of centering tools and small-diameter workpieces to
within 0.002 or 0.003 of an inch when firmly tightened.
(6) Hollow Headstock Spindle Chuck. The hollow headstock spindle chuck is
similar to a drill chuck but is hollow.
It is provided with threads to
screw it onto the headstock spindle nose. This chuck can be used to hold
rods, tubes, or bars which are passed through the headstock spindle. It is
generally capable of centering workpieces to an accuracy of 0.002 of an
inch.
(7) Collet Chuck.
(a) The collet chuck is the most accurate means of holding small
workpieces in the lathe.
The collet chuck consists of a spring machine
collet and a collet attachment which secures and regulates the collet on the
headstock spindle of the lathe.
(b) The spring machine collet (figure 15 on the following page) is a
thin metal bushing with an accurately machined bore and a tapered exterior.
The collet has three lengthwise slots to permit its sides to be sprung
slightly inward to grip the workpiece.
To grip the workpiece accurately,
the collet must be no more than 0.001 inch larger or smaller than the
diameter of the piece to be chucked.
For this reason, spring machine
collets are generally supplied in sets with various capabilities in 1/16,
1/32, or 1/64 inch increments.
For general purposes, the spring machine
collets are limited in capacity to 1 inch in diameter.
(c) The collet attachment which, with the spring machine collet, forms
the collet chuck and consists of a collet sleeve, a draw bar, and a
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