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

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