CNC Boring Machines

A CNC boring machine, or boring mill, is built for workpieces too large and too heavy for a machining center. A horizontal boring mill has a spindle that extends out of the headstock, the W axis, to reach deep into housings and bore accurate holes far from the column. Table-type machines move the part on a rotary table. Floor-type machines leave the part on floor plates and move the column along it, so the size of the part is limited mainly by the length of the bed.

Typical work is gearbox housings, large engine blocks, machine frames, turbine casings and heavy weldments. With milling heads and tool changers, a modern boring mill does most of what a machining center does, on a larger scale. For parts that fit on a pallet, look at horizontal machining centers. Bridge-type machines with a vertical spindle are listed under vertical machining centers.

Compare the spindle diameter and its W-axis travel, then the X, Y and Z travels and the table size and load. Spindle torque matters more than top speed for this kind of cutting. Look at the head attachments that are offered, since right-angle and universal heads decide how many faces can be reached in one setup.