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April 12, 2022

Achieving perfect concentricity with the SRT Reamer

SRT Reamer

The SRT, or Super Round Tool, is a patented reamer designed by the Northern Tool division of Star Cutter Company to create the best quality reamed hole across a spectrum of applications. The SRT combines two tools into one – it offers multiple straight flutes for consistent location and multiple helical flutes that ensure roundness and finish.

The SRT’s abilities include:

  • Superior surface finish (Ra, Rz, and Rmax)
  • Near-perfect concentricity
  • Roundness deviations of less than 2 µm
  • Lower cost per hole

Originally designed as a powdered metal valve guide reamer, the SRT is well-suited for many applications where finish and position are critical. It is available in right-hand spiral — right hand cut for blind hole applications, and left-hand spiral – right hand cut for forward flushing chips to open holes. Through manipulation of the straight flute position relative to C/L, helix, and rake angles it is possible to adjust the shear forces created.  This enables the SRT to finish a diverse group of materials.

Another benefit of the SRT is the innate ability to create its own path, straightening an often-inferior pre-existing or rough drilled hole. The combination of flute style and position also allows it to correct roundness issues that may be present as a result of sintering, casting, or pre-machined bores. The flute density (3 X 3 or 5 X 5) improves cycle time dramatically and can eliminate the need for post-ream operations such as honing, lapping, or roller burnishing.

Some successful applications include:

  • Compacted Graphite Iron (CGI)
  • Austempered Grey Iron (AGI)
  • Ductile Iron
  • Powdered Metal (resin and oil impregnated)
  • Alloyed Steels
  • Titanium
  • High Temperature Nickel Alloys
  • Aluminum
  • Brass
  • Industrial Plastics

If finish-hole quality and speed of operation are required, considering the patented SRT for your reaming needs will be beneficial.


Gary McCarel, Application Engineer

Click here for more information on the SRT Reamer


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