Johnford SL heavy-duty horizontal turning centers feature a 45˚ slant bed torque-tube design. The torque tube, or hole cast through the center of the slant bed, provides rigidity and dissipates heat. For optimum strength and accuracy, the machines are cast from rigid Meehanite iron.
Swing over the bed for the 11-machine series ranges from 15.7″ (5×9 mm) to 27.5″ (7×9 mm). Swings over the cross slide are 13″ (330 mm) and 21.5″ (546 mm). Distance between centers begins at 66″ (1,676 mm) and is 100″ (2,540 mm) on the largest machine. Bar capacity extends 1.7″ (43.2 mm) to 4.5″ (114 mm), depending on the machine.
Spindles provide 25 hp or 35 hp, delivered through a two-speed gearbox that supplies high torque at low rpm. The spindle structure is mounted with precision double row roller bearings in conjunction with angular contact ball bearings.
Square box ways provide the rigidity for heavy duty turning. All mating sliding surfaces are hand-scraped and coated with Turcite-B to allow high rapid traverse rates and accurate positioning. To ensure precision and thermal stability, the headstock, tailstock, and saddle all are mounted on the same plane at a 45˚ degree angle. The coolant tank is separate from the machine base to prevent heat transfer from the coolant to the machine casting. Double-nut-type ballscrews are pre-tensioned to eliminate thermal growth.
Fanuc CNC controllers are standard, as is a complete coolant system and a programmable hydraulic tailstock body and quill. A 12 station bi-directional servo turret or optional BMT live turret provides 0.3 second indexing as well as coolant-through the tool holders.
The machines can be tailored to meet specific production needs with options that include various live tooling packages, and tool presetting systems. A full C axis with live tools is available for applications requiring milling operations. Also available are Y-axis functionality and a selection of sub-spindle packages.
