Modern Machine Shop
Absolute Machine Tools offers the Johnford ST-80 CH, a high-precision CNC turning center for the oilfield, energy and construction industries. The 35,500-lb slant bed machine features bed lengths ranging to 240" and spindle holes as large as 24". The one-piece, 60-degree casting is designed to improve ergonomics and chip flow. The slant bed is a torque-tube design, which means a hole is cast through the center of the slant bed to provide rigidity and heat dissipation.
A 50-hp high-torque spindle motor and a standard four-speed gearbox deliver high torque at low rpms, and a 60-hp spindle motor is available for high-power cutting. The precision spindle structure is mounted with double-row roller bearings and angular contact ball bearings to increase rigidity and accuracy.
Hand-scraped square boxways provide rigidity for heavy-duty turning. Turcite B is applied to all mating sliding surfaces to ensure high rapid traverse rates and accurate positioning, the company says. The headstock, tailstock and saddle are mounted on the same plane at a 60-degree angle for precision and thermal stability. The coolant tank is separate from the machine base to prevent heat transfer from the coolant to the machine casting. The double-nut ballscrews are pre-tensioned to avoid thermal growth. A 12-station bi-directional turret or optional BMT live turret provides 0.5-sec. indexing as well as coolant through the toolholders. A full C axis with live tools is available for milling applications. FANUC CNC controls are standard.
Other features include a hydraulic 20" chuck with soft jaws, a chip conveyor and a hydraulic, programmable tailstock body and quill. An optional C axis with live tools is also available. The C axis accuracy is 0.001 degree.