Should You Use a Standard Twist Drill or Something More Specialized?

Twist drills are readily available in fraction, letter and number sizes. Depending on the material being drilled and the configuration of the hole required, there are optional choices of standard twist drills which will perform better than general purpose (GP) tools which are normally used. These include high helix for softer materials and certainly in blind holes where they easily lift chips from the hole.  But – is a standard twist drill ALWAYS going to cut it? If you require extremely precise holes or are drilling hundreds of thousands of holes, a special designed drill will most likely be preferred. Here are some examples: 

twist drill

  • Flute shape cutting angles and point geometry can all be maximized for the material and machine conditions presented. 
  • Step drills (for multi-diameter holes) and multiple margin drills (for close tolerance holes) perform effectively for their specific jobs  
  • Coating can be applied to improve tool life.

Special Drills to Consider

Other specialized drills conform to basic drill design but the spindle they are attached to necessitates a shank

twist drill image

configuration integral to the spindle.  Many of these drills are common in the aircraft industry.

  • Drivmatic and spacematic tools have shanks allowing the drill to be used portably in hand held devices normally associated with tight tolerance surface holes in the fuselage and wings of airplanes.
  • Nutplate drills are machine specific drills when used with jigs will produce a high volume of holes that are to size, concentric between countersink and drilled hole and start easily in difficult to machine materials. They are specifically for use with nutplate fasteners found in fuselages and other airplane structures.
  • Multi-flute core drills, usually four, produce close tolerance round holes without the need for reaming, and are frequently supplied as step tools assuring straight consistent size.
  • Parabolic flute design drills can be used in the same circumstances in tougher materials and deep holes.
  • Cobalt drills are designed for drilling tough materials and are constructed with a split point to ensure easy starting.

Regal Can Help You Find the Drill You Need

Not sure which type of drill is best for you? Regal engineers can help with all your drilling applications.