New Johns Hopkins Ruling Engine

New procedures of lapping and mounting of ruling engine screws are described. An inherently precise method of generating a dividing head with unmeasurable errors is described. A new design of ruling engine with two screws and with the work reciprocating, is described. This engine resembles a planer whereas the Rowland type engines resemble a tool room shaper. Fanned lines are not produced on the new engine. All components are designed for immunity to temperature, friction and wear. Gratings of 21-foot focus are currently being ruled 14,400 lines per inch with 1/10 percent Rowland ghost intensity in the first order. The ruled area is 518×318    in. All gratings show five components of Hg 5461 in the second order. The gratings are ruled in 67 hours. It is envisioned that grating production can be made adequate to satisfy the needs for gratings without recourse to replicas. The new engine is a pilot model for a larger engine planned for the future.