Johnford SV-48

The Johnford SV-48 marks the point where the SV series changes casting. Travels grow to 1,220 x 710 x 630 mm (48 x 28 x 24.8 in), the table to 1,300 x 700 mm (51.2 x 27.6 in), and the spindle-to-column distance to 740 mm (29.1 in). The SV-41 below it has 640 mm (25.2 in) to the column and 610 mm (24 in) of Y.

Three things change with the bigger frame, and a buyer moving up from the smaller models should know all of them. First, the standard 40-taper drive is a 7.5 / 11 kW (10.1 / 14.8 hp) motor with a Hi-Lo gear, still at 60~10,000 rpm; the SV-33 and SV-41 use a gearless P motor. Second, rapid traverse is 24 / 24 / 24 m/min (945 / 945 / 945 ipm), slower in X and Y than the smaller machines but faster in Z. Third, table load rises to 1,500 kg (3,300 lb).

The gearbox matters most. It gives the SV-48 low-range torque for roughing steel without giving up 10,000 rpm in high range, which fits the larger parts a 710 mm Y axis invites. An oil cooler for the spindle and gearbox is standard. Optional spindles are the 12,000 rpm cartridge type, a 15,000 rpm direct drive in BBT-40, and a built-in HSK A63 unit at 15,000, 18,000 or 20,000 rpm.

Johnford lists the machine at 7,000 kg (15,400 lb) and 3,200 x 3,900 x 3,090 mm (126 x 154 x 122 in). The floor plan is nearly 4 m deep, so plan the chip conveyor and electrical cabinet access before the machine is placed.