Armstrong's STC-628 CNC Automatic Circular Saw Topper

Armstrong’s second generation saw grinder is fast, precise and easy to use. It has the features you want, the capacity you need, sized to fit nearly every shop, at a price you can afford.

The tooth geometries for a nearly unlimited number of saws are stored on the hard drive of the built in Intel® Celeronä computer. Each saw is sharpened exactly the same way every time. Set ups are very fast; it takes just seconds to begin sharpening the next saw.

The full color touchscreen shows the operator a picture of the tooth to be ground. Icon-based graphics make the machine easy to set-up and run, even for non-readers.

The Armstrong Topper uses three CNC axes and a hydraulic feed axis for speed, versatility and accuracy.  It grinds the tops of saws from 6” (150 mm) to 28” (700 mm) diameters. Tooth spaces up to 3” can be sharpened. Options include a full enclosure, either water-based or oil coolant and a built-in de-mister for use with the enclosed model grinder.  This machine can be ordered as a dual function machine (STF-628) that both tops and faces your saws.

2135 NW 21st Ave. Portland, OR 97209 USA
(503) 228-8381  Fax: (503) 228-8384
Copyright Armstrong Mfg Co. 2002

STC-628 Topper Only Specifications:

  • Saw Diameter: 6" to 28" (150 to 700 mm)
  • Saw Eye Diameter: 1/2" to 9-5/8" (12 to 230 mm)
  • Tooth Space: 1/4" to 3" (6 to 76 mm)
  • Back Angle Range: 5 to 20 degrees
  • Top Bevel Angle Range: up to 45 degrees
  • Grinding Wheel Diameter: 6" (150 mm)
  • Grinding Wheel Speed: 5400 SFPM
  • Grinding Motor Rating: 1.5 HP (1 kW)
  • Air Requirements: 80 PSI
  • Size: 54” wide x 48” deep x 81” high (1375 x 1220 x 2050 mm) for the enclosed model
  • Final specifications may vary slightly to reflect latest design enhancements

STF-628 Topper & Facer Specifications:

  • Top grinds 6" to 24" (150 to 600mm)
  • Face Grinds 6" to 28" (150 to 700mm)
  • Face Grinds hook angles from 45 to -20 on saws up to 24" (600mm). Available option: hook angles from 45 to +20 on saws up to 28" (700mm).
  • Face bevels up to 15
  • All other specs same as STC-628 Topper Only


Armstrong's STC-628 CNC Automatic Circular Saw Topper                                      

The computer calculates all offsets for beveled and triple chip saws, so the faceplate never needs to be manually adjusted.  Operator can select to automatically reverse the rotation of the cup wheel to always grind onto the carbide or choose non-reversing operation for faster cycle times.


Oil coolant or water-based coolant: your choice.  The Armstrong CNC Top grinder can be supplied either way.  Fire suppression is available from Armstrong or we will help you work with your local supplier.  Whether you choose oil or water, two nozzles direct the coolant between the grinding wheel and the carbide tip.


All adjustments are made through a touch screen control panel that displays a picture of the finished tooth shape.  A built-in memory recalls the settings for a virtually unlimited number of saw configurations.


  • Intel® Celeronä PC control for speed and reliability
  • 3 axis brushless servo system for long life and precision control
  • Full color Touch screen for easy operation
  • Thousands of customized tooth shapes can be stored for fast set-ups and consistent grinding
  • Specialty saws with up to 40 teeth in a segment can be sharpened
  • Total control of stock removal, tooth configuration, wheel lift off, and grinding depth and speed
  • Available either totally enclosed or open: your choice.
  • Water-based or oil coolant available: your choice
  • No need to adjust for saw thickness. The machine calculates all offsets from the plate thickness and kerf values entered by the operator
  • Grinding wheel motor automatically reverses direction for right and left-hand teeth
  • Multiple pass per tooth capability
  • Optional mist removal system and coolant filtration systems are available at extra cost
  • STF-628 dual function model both tops (to 24" diameter) and faces (to 28" diameter) dependant on hook angle


"Smart finger” retracts as needed for any tooth space within the capacity of the machine, including variable pitch saws.  Saw loading and set-up times are very quick.  The saw has been removed to show the feed finger, faceplate, cup wheel, saw mandrel and clamp mechanism.