Acme-Gridley RA-6

The Acme-Gridley RA-6 is a multi-spindle bar automatic listed for bar up to 1-5/8 in (41 mm), depending on configuration, on a machine weighing approximately 18,000 kg (40,000 lb). The listed figures describe two different machines under one name: the original, in which cams drive everything, and a CNC retrofit, in which servos do.

That split runs through the whole table. The main spindle drive is either mechanical or AC servo. Cross slides and end-working slides are either cam-driven or CNC servo-driven. Spindle speed has no figure at all; it is given as variable and dependent on gearing and on the retrofit specification. Anyone evaluating an RA-6 therefore has to establish first which of the two they are looking at, because setup method, changeover time and the skills needed to run it are not the same.

On a cam machine the job lives in the cams and the gearing. A new part means a new or re-timed cam set, which pays off on long runs of one part and costs time on short ones. On a retrofit the slide motions are programmed, and the control is listed as Siemens, Fanuc or Allen-Bradley depending on the retrofit. Ask for the retrofit documentation, since the listed figures say nothing about the scope of any conversion.

Bar feed is listed as magazine or hydrodynamic, and coolant as a centralized flood system. Check the floor for the 18,000 kg (40,000 lb) weight before the machine arrives.