2006 Hankook Protec 11N CNC Flat Bed Lathe

The Hankook Protec 11N is a heavy-duty CNC flat bed lathe built for the shaft, roll, and oil-country work that overwhelms a standard turning center. This 2006 machine swings 43.3 inches over the bed and 29.1 inches over the carriage, turns up to 43.3 inches in diameter, and carries 118 inches between centers with a 17,600 lb load capacity - enough to hold a long, heavy shaft on centers and cut it end to end. Power comes from a 50 HP (37 kW) spindle motor through an automatic 4-step geared headstock spanning 1 to 800 RPM, so full torque is available at the low speeds big-diameter roughing demands. The 105 mm (4.13 inch) spindle bore on an A2-15 inch nose passes bar and tube stock, and a 32 inch 4-jaw independent chuck grips odd-shaped and off-center work. Travels are 24.4 inches in X and 118 inches in Z, with rapids of 157 IPM and 236 IPM. The heavy MT#6 tailstock carries a 7.9 inch quill with 11.8 inches of travel, and a roll chock stand supports work from 15.7 to 31.5 inches. It all sits on a one-piece cast iron flat bed 31.5 inches wide and 226 inches long with induction-hardened, precision-ground guideways and high-precision ball screws on both axes, under Fanuc 21i-TB CNC control.

Against the earlier non-N Hankook Protec lathes it replaced, the Protec 11N is a rebuilt machine rather than a facelift. Hankook moved the main spindle to a three-point support system - double-row cylindrical roller bearings front and rear with an angular ball bearing up front - and made all spindle bearings precision-class and permanently grease-lubricated to hold thermal growth down through long cuts. The headstock gained automatic 4-step gear changing, so nobody stops the machine to shift ranges by hand moving from roughing to finishing. Both axes run high-precision ball screws driven by servo motors, and the longitudinal and cross handles work through pulse generators rather than coupling straight to the screw - which is what lets Hankook's Guidance Handwheel deliver manual feed, automatic mechanical feed, and true simultaneous two-axis circular turning from the handwheels. That matters on a machine this size: a machinist who came up on manual engine lathes can run the 11N by hand the day it lands and grow into the Fanuc control, while the induction-hardened ways, fluorine-resin way lubrication, and built-in rotary tailstock spindle with rapid feed keep accuracy and cycle times where a CNC buyer expects them.