Literature is available for Levin lathes
A special Levin lathe, intended only for the turning of very accurate balls, this model had a V-edged bed with a slide-rest mounted longitudinally and feeding towards and away from the headstock. On top of the bed slide was a short cross slide - adjustable over a limited range - topped by a swivelling slide with a built-in ruler and a simple but particularly rigid toolholder carried on a sloping surface by which means the tool height could be adjusted over a small range. Both upper slides were equipped with adjustable stops and the swivelling slide with a ball-tipped lever by which means the assembly could be rotated by the operator.
A variable speed motor was fitted, held within the base and driving to a pulley overhung on the left-hand end of the spindle.
Pictures of a Levin ball-turning (radius-turning) slide rest are here.