The 400 Lathe was Smart and Brown's most powerful lathe.
It was built to celebrate Smart & Brown's 40th anniversary. It was reported to take a 1" cut on dia without even a flicker from the amp meter. The name 400 is in relation to the swing over the Bed (400mm). It's power unit was a D.C SHUNT wound with thyristor, it's frame was a D160 foot mounted with Force vent cooling side mounted fan, giving with the controller a speed range of 50 to 4,700rpm at 50Hz Field weakening to give 10.7 Kw (14.3 hp) at 1000 rpm. The 1000mm between centres model weighed in at 2.7 tons, the 1500mm at 2.9 tons.