Types of Drill Bits Explained - Twist, Spade, and Countersink Designs #30286 (License: Personal Use)

This black-and-white line illustration details three essential drill bit designs: a central twist drill with helical flutes for chip removal, a left-side spade bit with a flat cutting head for fast wood boring, and a right-side countersink bit with a tapered tip for creating chamfered holes. Each bit is rendered with precise cross-hatching to indicate material thickness and cutting geometry, typical of early 20th-century engineering manuals.

Used in educational content, tool catalogues, or DIY guides to help users identify and select appropriate drill bits for specific materials and tasks; matches user intent to understand tool functionality before purchasing or using.