Page:Practical Treatise on Milling and Milling Machines.djvu/167

Rh Cutting a Spur Gear, Using the Spiral Head

Cutting a spur gear on a milling machine is a comparatively simple operation, as can be seen from the illustration. No special rigging whatsoever is required. The blank in this case is fastened on an ordinary lathe arbor mounted on the centres and dogged to the spiral head spindle.

In commercial manufacturing, gears such as that shown would be produced in quantities on automatic gear cutting machines, but where only an occasional gear is wanted, such as in replacing a broken one, it is advantageous to cut it on a milling machine. A new gear for a machine can usually be secured in this manner far quicker than it can be ordered and delivered.