Colchester Magnum HD CNC 1275

The Colchester Magnum HD CNC 1275 is the largest CNC lathe Colchester lists: 1,275 mm (50.2 in) of swing over the bed and 1,015 mm (40.0 in) over the cross slide. It can turn a part more than a metre in diameter along the whole bed, on lengths from 1.5 m to 6 m between centres.

Its headstock options are identical to those of the Magnum HD CNC 1135. That means eight spindle bores up to 420 mm (16.5 in), noses from A2-11 to A2-28 and a base motor of 30 kW (40.2 hp) with 37 kW (49.6 hp) or 45 kW (60.3 hp) to order. What the buyer gains with this model is swing: 1,015 mm (40.0 in) over the cross slide against 875 mm (34.4 in) on the Magnum HD CNC 1135. For big rolls, turbine and generator shafts, ship components and large flanged work, that clearance decides whether the job fits at all.

At these diameters surface speed is reached at very low revolutions, and the maximum speeds reflect that. They are listed per bore as 700 / 550 / 500 / 500 / 500 / 400 / 400 / 300 rpm. A user planning to finish small journals on a large forging should check the top speed of the chosen bore.

Foundations, craneage and workholding deserve as much attention as the lathe. The product page gives no weight or floor loading, so those have to come from Colchester with the quotation. On the machine itself, the one-piece floor-type bed casting, 4-way hydraulic tool post, carriage driven tailstock and rear swarf conveyor are standard. Steady rests, hydraulic chucks, rear chucks and a C-axis with driven tool turret are optional.