Johnford HT Series of twin-turret 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 rigidity and dissipates heat. For optimum strength and accuracy, the machines are cast from rigid Meehanite iron.
Swing over the bed for the seven-machine series ranges from 22.8″ (579 mm) to 27.95″ (710 mm), with 39.4″ (1000 mm) optional. Swings over the cross slide are 13″ (330 mm) and 23.6″ (600 mm), with 31.5″ (800 mm) optional. Distance between centers begins at 21.7” (551 mm) and is 120″ (3048 mm) on the largest machine.
Twin 12-tool turrets are standard on all machines, and C-axis, Y-axis, and sub-spindle are optional.
A wide variety of available spindle types are available. Depending on the machine model, the spindle has 25-60 hp and a 2 or 4 speed gearbox. Spindle structures 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, thus ensuring concentricity and accuracy.
Square box ways provide rigidity for heavy turning, and hand-scraped sliding surfaces are coated with Turcite B to enable high rapid traverse rates and accurate positioning. Double-nut ballscrews are pre-tensioned to minimize thermal growth.
The headstock, tailstock and saddle all are mounted at a 45˚ angle on the same plane to ensure precision and thermal stability. The coolant tank is separate from the machine base to prevent heat transfer from the coolant to the machine casting, maximizing precision and promoting easy cleanout and maintenance.
A chip conveyor and a programmable hydraulic tailstock are standard equipment. The machines can be tailored to meet specific production needs with options that include various live tooling packages, Y- and C-axis functionality, high-power spindles, axial and radial live tool heads, and tool presetting systems.
