Fig. 391 shows a fixture used in boring out the head casting of a ball-bearing lathe. In this fixture, the casting is held while being bored. As the spindle holes are located by the bushed holes for the boring bar, it is perhaps more of a "jig" than a "fixture". However, its use is evident from the cut.

Planer Fixtures

Planer fixtures are usually simpler in design and construction than those in use on either the boring or the milling machine. Fig. 392 is illustrative of the simplicity of planer fixtures. The cut shows it as made for holding a string of square tables such as are used on sensitive drillers. As shown in the illustration, a double string of tables are mounted and both of the tool heads are used.