Page:Practical Treatise on Milling and Milling Machines.djvu/211

Rh Boring Holes in Jig

The use of a scale and vernier in connection with a boring bar, boring holes where accurate spacing is required, is shown in this operation. Finer adjustments can be obtained in this way than are possible using the dial on the longitudinal hand feed screw.

The work is strapped to the table, and the boring bar, which is in reality a kind of fly tool, is held in a collet inserted in the spindle. Scales and verniers can also be furnished for the transverse and vertical movements of Brown & Sharpe milling machines.