Machines in the Johnford GT Series of eight large, heavy duty horizontal slant bed turning centers feature a one piece, 45˚ slant bed torque tube design. The torque tube, or hole cast through the center of the slant bed, maximizes bed rigidity and dissipates heat. For optimum strength and accuracy, the machines are cast from rigid Meehanite iron.
The machine saddle casting is inclined at 60˚ to allow for the larger swing and capacities. Swing over the machine bed is 61″ (1,549 mm) and swing over the cross slide is 50″ (1270 mm). Distance between centers range from 40″ (1,016 mm) to 240″ (6,096 mm). All machines feature a single 12-tool turret and C-axis is optional.
Square box ways provide rigidity for heavy-duty turning. Hand-scraped sliding surfaces are coated with Turcite B to all enable high rapid traverse rates and accurate positioning. Pre-tensioned double-nut ballscrews minimize thermal growth.
A wide variety of spindles is available, with power ranging from 50 hp to 100 hp delivered through a 4-speed gearbox. The spindle structure is mounted with double row roller bearings in conjunction with angular contact ball bearings for high rigidity and accuracy. The spindle quill inner and outer linings are precision ground for fit with the spindle, to provide extreme concentricity and accuracy. A 24″ 3-jaw chuck is standard, as is a programmable hydraulic tailstock body and quill. Larger chucks, high-pressure coolant systems, tool presetting systems, radial and axial live tooling heads, and 12-station live tooling with a full contouring C axis are among the available options that enable the machines to be tailored to specific production needs.