Single Flute Extended Length Gundrill

Contact Details

5200 Prairie Stone Pkwy., Ste. 100
Hoffman Estates
United States

42.0736282, -88.2089549

October 11, 2022
Drills Designed to Machine Straight Deep Holes

Star SU, part of the Star Cutter family of companies, announces its single flute extended length gundrills, which are custom-built drills per application that can be produced in lengths up to 24.0“ [610mm) and effective tool lengths up to 100 x D. These drills are designed to machine straight deep holes and hold excellent finishes in virtually any material. 

In real-world applications, these gundrills have numerous benefits including:

  • Higher chip load capability, helping reduce cycle time
  • Reduced drift, which allows excellent TIR results from start to exit
  • Increased resistance to wind-up forces, helping reduce premature tool wear
  • Increased distances for unsupported lengths over traditional gun drills
  • Ability to recoat tool after regrinding if manufactured without a steel driver

In a field study on an aluminum cylinder head, the application of the extended drill was able to achieve a tool life of 2,000 parts per drill when machining holes of 8 mm diameter at 5,000 RPM in the cut and a feed rate of 1200mm/minute. Prior to the deep hole gundrill operation, there were two twist drill passes with the gundrill connecting the center portion of this feature in the head.

Related Glossary Terms

  • feed


    Rate of change of position of the tool as a whole, relative to the workpiece while cutting.

  • gundrill


    Self-guided drill for producing deep holes with good accuracy and fine surface finish. Has coolant passages that deliver coolant to the tool/workpiece interface at high pressure.

  • total indicator runout ( TIR)

    total indicator runout ( TIR)

    Combined variations of all dimensions of a workpiece, measured with an indicator, determined by rotating the part 360°.

  • twist drill

    twist drill

    Most common type of drill, having two or more cutting edges, and having helical grooves adjacent thereto for the passage of chips and for admitting coolant to the cutting edges. Twist drills are used either for originating holes or for enlarging existing holes. Standard twist drills come in fractional sizes from 1¼16" to 11¼2", wire-gage sizes from 1 to 80, letter sizes A to Z and metric sizes.