This model was introduced in the late 1950’s by Arter Grinding Machine Company just before they sold out to Sundstrand.  This model was available only in 12” and had lower horsepower and the table was able to slide due to the rack and pinion from a reversing mechanism.  It is assumed that these features were introduced for economic purposes.  It was a mechanically operated machine as contrasted with the Model E which is hydraulically operated.  This model was obsoleted soon after its introduction. 