EMAG G 250

The EMAG G 250 grinds gears up to 250 mm (10 in) in diameter and 550 mm (21.5 in) long, across a module range of 0.5 - 7.0 mm and a face width of up to 380 mm (15 in). The helix angle runs to +45 / -45 °, and the control is a Siemens 840 D sl.

The long face width is the figure that separates it from the smaller G 160, which stops at 180 mm (7 in). At 380 mm (15 in) the G 250 can grind wide spur and helical gears and gear sections on shafts, and the 550 mm (21.5 in) workpiece length leaves room for the shaft ends beyond the toothing. The top module of 7.0 mm also takes it into heavier gearing than the 4.0 mm limit of the G 160.

The grinding wheel is 180 mm (7 in) wide and runs at 80 m/s. Its diameter is listed as 170 / 250 mm (6.5 / 10 in) with no label; on the G 160 the equivalent row is given as a maximum and a minimum, which suggests the same reading here, but confirm which is the new-wheel size before ordering wheels. Dressing uses a tool of 120 mm (4.5 in) diameter.

The G 250 HS uses the same 250 mm workpiece diameter, 550 mm (21.5 in) length and 380 mm (15 in) face width, but its table lists a 20,000 rpm grinding spindle and separate generating and profile grinding wheels of 160 / 68 mm and 160 / 30 mm. Where the G 250 table describes one larger wheel at 80 m/s, the HS describes smaller wheels at high spindle speed, so the choice turns on whether the parts have interference contours that only a small wheel can clear.