Groove Spiral Duct Liner In Seconds

The Glass Master SG-420 Grooving Machine fabricates high quality fiberglass spiral duct in seconds, grooving duct board 40 to 50 times faster than standard hand cutting techniques. Four drive rollers and a ¾ hp motor provide the grip and power to quickly pull duct board through the 21 tools required to form spiral duct liner. The SG-420 also grooves board for square and rectangular duct.

The SG-420 spiral duct liner grooving tools utilize precision-ground and hardened blades, producing clean grooves and consistent dimensions. The tool set includes (19) - 18° Vee blades, (1) - 9° Flap blade, and (1) standard cut-off blade. Square and rectangular duct is grooved with SG-220 cutting tools. Quick release clamps on all tools allow for fast and easy adjustment.

Standard Features

  • Rugged structural steel construction
  • Durable powder coat finish
  • Foot-actuated switch for safe, dependable operation.
  • Easy access to all working parts.
  • Swivel casters, two with brakes

Optional Accessories

  • Tool Sets with blades for 1", 1-1/2" and 2" board
  • Board support arms (set of 3)
  • Catch table
  • Tool support bar

See the Tools and Accessories page for a complete list of available accessories, tool holders and blades.

Technical Information


  • Length: 130"
  • Depth: 41"
  • Height: 49"
  • Weight: 1,500 lbs


Technical Info

  • Power requirements: 120V, single phase, 50hz or 60hz. Less than 15 amps required at maximum load. 
  • Board feed rate: one linear foot per second (0.3 m/s)