Johnford SL-30

An 8 in chuck and an 11 / 15 kW (14.8 / 20.1 hp) spindle make the Johnford SL-30 the general-purpose size of the small SL turning centers. Bar capacity is Ø51 mm (Ø2 in), the spindle nose is A2-6 and top speed is 4,500 rpm.

It shares its bed with the SL-20. Both have Ø400 mm (Ø15.7 in) of swing over the bed, Ø330 mm (Ø13 in) over the cross slide, 180 mm (7.1 in) of X and 600 mm (23.6 in) of Z, and the same 1,851 x 1,862 mm (72.9 x 73.3 in) cross-section. The SL-30 puts twice the motor power on that bed, with a Ø100 mm (Ø3.9 in) spindle bearing against Ø90 mm (Ø3.5 in) on the SL-20.

Power without gearing has a limit, and the table is plain about it: the transmission is one step. Torque for large-diameter roughing in steel therefore depends on the motor alone. Johnford offers a 2-speed belt-type gearbox as an option for this size, and it is the option to consider if the work is forgings and castings near the 8 in chuck's capacity instead of bar.

The saddle is inclined at 30° and all axes run on box ways, which is a heavier construction than linear guides and suits interrupted cuts. Tailstock travel is 500 mm (19.7 in); the quill is hydraulic, with an MT#4 fixed centre and an MT#3 rotary quill as an option. The machine weighs 4,000 kg (8,800 lb).