Page:Practical Treatise on Milling and Milling Machines.djvu/169

Rh Gashing Teeth in Worm Wheel

Finishing a worm wheel on a milling machine requires two separate operations. First, the operation of gashing the teeth, shown above, is performed; and then the teeth are hobbed, as shown in the illustration on page 164.

In gashing the teeth, the blank is dogged to the spiral head spindle, and the swivel table is swung to the required angle. The vertical feed is used and the teeth are indexed the same as in cutting a spur gear. Most of the stock is removed in gashing, only enough being left to allow thte hob to take a light finishing cut.