Drilling

Drill press

Drilled hole in plastic

Bolt hole pattern made by CNC drilling

Drilling is a cutting process in which a hole is made by means of a multi-point, fluted, cutting tool that rotates as it plunges into the material. Drilling on manual presses offers low cost for simple short runs. Drilling is primarily done on CNC machines including milling machinies and lathes. Drilling produces round holes, typically for machine screws and bolts. Drilling can process metals, hard plastics, wood and most other rigid materials.

Cost reduction options for drilling include minimizing hole count, reducing hole depth and reducing the number of different hole sizes.

Drilling Design Considerations

• Avoid high ratios of length to diameter
• Consider that high ratios of length to diameter complicate achieving high tolerance on the position of the exit side of the hole.
• Consider specifying to drill from both ends when higher position tolerance is required.
• For holes to be tapped, the drilled hole should be several threads deeper than the thread.