Johnford SL-70A-2S

The Johnford SL-70A-2S moves the twin-spindle idea onto the large SL bed. Swing over the bed is Ø700 mm (Ø27.6 in), swing over the cross slide Ø540 mm (Ø21.3 in), and the two spindles are up to 1,400 mm (55.1 in) apart.

It weighs 14,000 kg (30,800 lb), nearly twice the 7,800 kg (17,160 lb) of the SL-60A-2S, while the spindles themselves stay as they were. Main: 12 in chuck, 22 / 26 kW (29.5 / 34.9 hp), 2 step automatic transmission, 3,000 rpm. Sub: 8 in chuck, 11 / 15 kW (14.8 / 20.1 hp), 4,500 rpm. The gain is in the structure and in the space around the part.

That space shows in three rows. X travel is 295 mm (11.6 in). The Y-axis, where fitted, has ±50 mm (±2 in) and a 3.8 kW servo motor, where the SL-60A-2S has ±40 mm (±1.6 in). And the table lists a single swing over the cross slide, Ø540 mm, with no reduced figure for the Y-axis version.

Parts that call for it combine a large diameter with length: rotor shafts with a wide body, long flanged spindles, big valve stems with a head, rollers with stub ends machined after the body. One end is driven by the main chuck; the other is taken by the sub-spindle for the second operation.

Rapids are lower than on the medium bed, 12 / 10 / 15 / 15 m/min (472 / 394 / 591 / 591 ipm). The machine is 6,800 mm (267.7 in) long and 2,520 x 2,200 mm (99.2 x 86.6 in) in section.