Page:Practical Treatise on Milling and Milling Machines.djvu/145

Rh

Gutting Two Grooves in Six Steel Gores at One Traverse on a No. 5 B Heavy Plain Milling Machine

This illustration shows an unusually heavy milling operation, consisting of cutting two grooves, each 1.17" wide and $5⁄16$" deep, in six steel forgings at one traverse of the table.

Three sets of index centres of a special design are employed, and two steel cores are mounted on the arbor on each pair of centres.

The cutters are of a special form to cut two grooves and the top of the intervening space between the grooves.

For such a cut as this, a large arbor is required, and it must be very rigidly supported; intermediate arbor yokes are, therefore, placed between the cutters.

Lard oil is used as a cutting lubricant.