Jigs and Fixtures 205
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d:\N-Design\Des14-1.pm5
14.5.3 Set Blocks
Cutter set blocks are fastened to the fixture body for proper positioning of the cutter/tool
(Fig. 14.7). The locating surfaces of the set blocks are off-set from the finished surfaces to be
machined. Feeler guages, in thickness equal to the off-set are used on the locating surfaces of
the set blocks and then the fixture is adjusted until the cutter touches the feeler guage.
Work piece
Clamp
Movable
member
Setting block
Indexing device Tenon
Locking device Body
Thrust bearing
Fig. 14.7 Milling fixture
14.6 Types of Fixtures
14.6.1 Indexing Type Milling Fixture
Figure 14.7 shows an indexing type milling fixture, consisting of various components. The
fixture base is fixed on the milling machine table, and is aligned by means of the tenons fitted
to the base. The cutter is set by using a feeler guage and setting block. After making a cut on
the work piece, it is indexed for the next slot, using the indexing mechanism.
14.6.2 Turning Fixture
Figure 14.8 shows a turning fixture to drill and finish a bearing block. The base of the fixture
is clamped to a face plate/back plate of lathe. To compensate for the unbalanced loading over
the lathe spindle, a balance weight is provided on the fixture base.
