MACHINE SHOPS -Spartan Mfg. Manufacturing - Precision screw machine shop using Davenport multispindle screw machines, acme Gridley''s and CNC machines for high and low volume parts manufacturing. Manufacturer from print to finish product for aerospace and commercial. Precision screw machine shop using Davenport multispindle screw machines, acme Gridley''s and CNC machines for high and low volume parts manufacturing. Manufacturer from print to finish product for aerospace and commercial