Citizen Miyano BNA-42DHY

The Miyano BNA-42DHY is a compact two-spindle, two-turret lathe for 42 mm (1.65 in) bar on the main spindle and 34 mm (1.34 in) on the sub spindle, with an 8-station upper turret, a 6-station lower turret and a 70 mm (+/-35 mm) Y stroke. It is not in Citizen's current lineup, so most buyers will be looking at a used machine.

Only the upper turret is live. All 8 of its stations can take revolving tools, which run 50 - 5,000 RPM on a 2.8/1.0 kW motor; the lower turret's revolving-tool count is listed as 8/---, so it carries stationary tools. In practice that puts every milled flat and cross hole on the upper turret, while the lower turret handles turning, drilling on centre and cut-off support at the sub spindle.

The main spindle turns 60 - 6,000 RPM with 7.5/5.5 kW (10/7.5 hp), the sub spindle 50 - 5,000 RPM with 5.5/3.7 kW (7.5/5 hp). Chucks are 5 inch and 4 inch, collet chucks are the stationary type and both spindle noses are a special flat type. Maximum machining length is 100 mm (3.94 in).

The turrets index in 0.2 sec/station by AC servo motor and curvic coupling. Travels are 140 mm (5.51 in) on X1, 235 mm (9.25 in) on Z1, 140 mm (5.51 in) on X2 and 360 mm (14.17 in) on Z2, with rapids of 20 m/min (787 ipm) on X1, Z1 and Z2 and 12 m/min (472 ipm) on Y and X2. The machine weighs 3,100kg, stands 1,700mm tall on 2,350×1,450mm of floor and runs a Mitsubishi CNC.