P428 Pollard "Corona" drills. Full-range catalogue showing drills from the smallest to largest as sold in the style current circa 1920s to 1930s.
 

POLLARD 20MH and 20MX Multi-spindle Drilling Machine. Operating Manual,
Maintenance Manual and Parts Manual as Exploded Component Diagrams. Includes
and electrical diagram and maker's Sales & Technical Specification Catalogue.