Page:Practical Treatise on Milling and Milling Machines.djvu/132

126 Milling End and Slot in Spiral Head Work Drivers on a No. 3 B Heavy Plain Milling Machine

Several of these work drivers are placed in the special fixture shown and clamped by means of the set screws at the side and end.

The cutter at one traverse mills the curved end and the deep slot in the plates. Then the set screws are slackened, each plate is reversed in the fixture, and the other ends are milled to duplicate the first.

The middle cutter is $7 1⁄2$" in diameter, and as the cut is taken from solid steel, a heavy machine with rigid support for the cutter arbor is required. Lard oil or soda water is used as a cutting lubricant in this operation.