A series of vertical CNC honing machines provide a closed-loop control of tool feed to make holes with accuracies to 10^-6 in., in sizes from 0.120 to 2.56-in. diameter. Air-gaging systems on SV-1500 machines from Sunnen Products Co. in St. Louis, Mo. (sunnen.com) let the machines hone holes without operator intervention. Setup is simple. A three-axis hand wheel fine-tunes tool feed as well as a servo-controlled stroke and a rotary table. The air-gaging system regulates bore diameter and geometry by measuring a part after it's machined and while still fixtured.

The CNC includes an autocorrect feature for bore shape. Using measurements from the air-gaging system, the autocorrect feature lets operators select from a library of “problem bore” images — such as tapers and barrels — to match to a problem part on the machine. The stroke system corrects the problem by dwelling in necessary areas of the bore, end-to-end, selectively removing stock for precise straightness and roundness.

SV-1005s have a cast polymer base and cast-iron column that provide vibration damping for precision honing. Removable stainless-steel side doors allow attaching the machines to automated part-loading systems. A high-torque, belt-driven spindle is rated at 10 hp, for a wide range of sizing and finishing work.