Page:Practical Treatise on Milling and Milling Machines.djvu/140

134 Milling Ways on a Screw Machine Bed on a No. 4 B Heavy Plain Milling Machine

The value of gang milling, and the advantages of the milling machine over the planer, are very apparent in this operation, for it is essential that the ways on every bed be exact duplicates in width and distance apart. Once the gang of cutters is accurately set, each succeeding casting must necessarily be a duplicate of the first.

The bed has a boss cast on each end by means of which it is clamped directly to the table. After milling, the two bosses are taken off.

The gang of cutters is composed of four side milling cutters, and two plain spiral milling cutters with nicked teeth. The arbor is firmly supported in the arm braces, and the arbor yoke is employed to bring a bearing nearer the cutters.