8274-4 PLANETARY GRINDER AND POLISHER

Model: 8274-4

The 8274-4 is the only grinder on the market offering 3 HP at 115 volts while operating at a 230-volt level. With variable speed and a soft start to control its amperage draw, the 8274-4 adjusts to the needs of small or large jobs. This machine is well suited for removal of thin-set, coatings, adhesive, prepping concrete for overlays or coatings, and polishing.

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Features

  • Three-part adjustable angle handle
  • Choose from 15A or 20A circuit-breaker settings with a convenient switch on the side of the controller; the 15A selection limits motor draw to 15 amps; 20A selection pulls up to 20 amps.
  • Forward and reverse directional controls increase tooling productivity with cleaner consumables and more even wear
  • Variable speed control
  • Dual rear vacuum ports
  • Flip-style weights for added or decreased head pressure
  • Removable handle and weights for easy transport
  • 18-inch grinding path; uses National's patented self-tensioning, single belt design to prepare concrete surfaces to a 3000 resin shine
  • Adjustable velcro dust guard lets the machine operate within an eight of an inch of walls and promotes nearly dustless operation
  • Grinder head rotates 90 degrees for easy tooling change access; Morflex couplers, polishing undulating concrete surfaces or creating a uniform scratch pattern for coating applications; operates a complete dry grind and polish system to eliminate messy and hazardous slurry

Specifications

Specifications Standard Metric
Width 20" 51 cm
Disc Size 18.5" 47 cm
Max. Height 52" 132 cm
Min. Height 27.5" 70 cm
Max. Length 75" 191 cm
Weight 388 lb 176 kg
Motor RPM 1740
Voltage 115
Frequency 60 Hz
HP 3 2.24 kW
Amps 15 or 20 - controller can switch between both settings
Drum RPM 133.8
Motor Phase Single

PCDs & Carbides

Part # Name Standard Metric Description Fits    
9555 9555 2-UP PCD- MICRO

Designed for aggressive concrete stock removal as well as coatings, glues, mastics, and other floor covering adhesives. PCDs and carbides can be used with all National planetary grinder machines. Remove heavy stock, adhesive, thin set, and epoxies

HELIX, 8274-4
9556 9556 2-UP PCD- 1/2 ROUND

Designed for aggressive concrete stock removal as well as coatings, glues, mastics, and other floor covering adhesives. PCDs and carbides can be used with all National planetary grinder machines. Removes heavy stock, adhesive,thin set, and epoxies

HELIX, 8274-4
9557 9557 4-UP PCD- MICRO

Designed for aggressive concrete stock removal as well as coatings, glues, mastics, and other floor covering adhesives. PCDs and carbides can be used with all National planetary grinder machines. Removes heavy stock, adhesive, thin set, and epoxies

HELIX, 8274-4
7268-2 7268-2 CARBIDES

Designed for aggressive concrete stock removal as well as coatings, glues, mastics, and other floor covering adhesives. PCDs and carbides can be used with all National planetary grinder machines. Removes coatings, glues, thin set, and thin mastics

HELIX, 8274-4

Diamonds

Part # Name Standard Metric Description Fits    
9522-50 9522-50 BRAZED TRAPEZOID DIAMOND

50 Grit: Prep concrete for reapplication and polishing. Used primarily in light industrial and residential applications for concrete grinding and profiling as well as sealer and top coat removal. Provide excellent surface profiles for new coatings, epoxies, or stains. Also create exceptional profiles for concrete preparation and restoration prior to polishing concrete. Brazed trapezoids can be used with all National planetary grinders.

HELIX, 8274-4
9507-30 9507-30 METAL BOND DIAMOND - HALF BAR

30 Grit: Remove sealers and preps concrete for polishing. Used for light, medium, and aggressive concrete grinding and profiling as well as sealer and top coat removal. Can be used for both residential and industrial applications. Perfect for leveling concrete high spots and repairing imperfections as well as creating the perfect profile for accepting new coatings and epoxies, or preparing concrete for polishing. Metal bond diamonds can be used with all National planetary and passive planetary grinders.

HELIX, 8274-4
9235-50 9235-50 5-INCH BRAZED DIAMOND

50 Grit: Create a "broom finish" on soft concrete surfaces; first stage to polishing concrete. Used primarily in industrial applications for medium to aggressive concrete grinding and profiling as well as sealer and top coat removal. Perfect for concrete preparation and restoration prior to concrete polishing. In addition, brazed diamonds effortlessly remove stains and imperfections from exterior wood decking while simultaneously profiling wood for receiving new stains and/or sealers. These polishing pads are for use with all National planetary grinders.

HELIX, 8274-4
9508-30SB 9508-30SB METAL BOND DIAMOND - FULL BAR

30 Grit: Remove various coatings, and profiles on HARD concrete only. Used for light, medium, and aggressive concrete grinding and profiling as well as sealer and top coat removal. Can be used for both residential and industrial applications. Perfect for leveling concrete high spots and repairing imperfections as well as creating the perfect profile for accepting new coatings and epoxies, or preparing concrete for polishing. Metal bond diamonds can be used with all National planetary and passive planetary grinders.

HELIX, 8274-4
9235-100 9235-100 5-INCH BRAZED DIAMOND

100 Grit: Create a "broom finish" on soft concrete surfaces; first stage to polishing concrete. Used primarily in industrial applications for medium to aggressive concrete grinding and profiling as well as sealer and top coat removal. Perfect for concrete preparation and restoration prior to concrete polishing. In addition, brazed diamonds effortlessly remove stains and imperfections from exterior wood decking while simultaneously profiling wood for receiving new stains and/or sealers. These polishing pads are for use with all National planetary grinders.

HELIX, 8274-4
9522-16 9522-16 BRAZED TRAPEZOID DIAMOND

16 Grit: Remove paint, stain, and sealers; preps concrete for reapplication. Used primarily in light industrial and residential applications for concrete grinding and profiling as well as sealer and top coat removal. Provide excellent surface profiles for new coatings, epoxies, or stains. Also create exceptional profiles for concrete preparation and restoration prior to polishing concrete. Brazed trapezoids can be used with all National planetary grinders.

HELIX, 8274-4
9507-30HB 9507-30HB METAL BOND DIAMOND - HALF BAR

30 Grit: Remove various coatings, and profiles on SOFT concrete only. Used for light, medium, and aggressive concrete grinding and profiling as well as sealer and top coat removal. Can be used for both residential and industrial applications. Perfect for leveling concrete high spots and repairing imperfections as well as creating the perfect profile for accepting new coatings and epoxies, or preparing concrete for polishing. Metal bond diamonds can be used with all National planetary and passive planetary grinders.

HELIX, 8274-4
9522-30 9522-30 BRAZED TRAPEZOID DIAMOND

30 Grit: Prep concrete for reapplication and polishing. Used primarily in light industrial and residential applications for concrete grinding and profiling as well as sealer and top coat removal. Provide excellent surface profiles for new coatings, epoxies, or stains. Also create exceptional profiles for concrete preparation and restoration prior to polishing concrete. Brazed trapezoids can be used with all National planetary grinders.

HELIX, 8274-4
9507-6 9507-6 METAL BOND DIAMOND - HALF BAR

3 Grit: Remove thin epoxy, paint, adhesives and sealers. Used for light, medium, and aggressive concrete grinding and profiling as well as sealer and top coat removal. Can be used for both residential and industrial applications. Perfect for leveling concrete high spots and repairing imperfections as well as creating the perfect profile for accepting new coatings and epoxies, or preparing concrete for polishing. Metal bond diamonds can be used with all National planetary and passive planetary grinders.

HELIX, 8274-4
9510-30 9510-30 METAL BOND DIAMOND - PROFILING DIAMOND

30 Grit: Prep high-/moderate-density concrete for reapplication. Used for light, medium, and aggressive concrete grinding and profiling as well as sealer and top coat removal. Can be used for both residential and industrial applications. Perfect for leveling concrete high spots and repairing imperfections as well as creating the perfect profile for accepting new coatings and epoxies, or preparing concrete for polishing. Metal bond diamonds can be used with all National planetary and passive planetary grinders.

HELIX, 8274-4
9508-16 9508-16 METAL BOND DIAMOND - FULL BAR

16 Grit: Remove epoxy as well as heavy and light sealers. Used for light, medium, and aggressive concrete grinding and profiling as well as sealer and top coat removal. Can be used for both residential and industrial applications. Perfect for leveling concrete high spots and repairing imperfections as well as creating the perfect profile for accepting new coatings and epoxies, or preparing concrete for polishing. Metal bond diamonds can be used with all National planetary and passive planetary grinders.

HELIX, 8274-4
9522-100 9522-100 BRAZED TRAPEZOID DIAMOND

100 Grit: Prep concrete for polishing. Used primarily in light industrial and residential applications for concrete grinding and profiling as well as sealer and top coat removal. Provide excellent surface profiles for new coatings, epoxies, or stains. Also create exceptional profiles for concrete preparation and restoration prior to polishing concrete. Brazed trapezoids can be used with all National planetary grinders.

HELIX, 8274-4
9508-16SB 9508-16SB METAL BOND DIAMOND - FULL BAR

16 Grit: Remove various coatings, and profiles on HARD concrete only. Used for light, medium, and aggressive concrete grinding and profiling as well as sealer and top coat removal. Can be used for both residential and industrial applications. Perfect for leveling concrete high spots and repairing imperfections as well as creating the perfect profile for accepting new coatings and epoxies, or preparing concrete for polishing. Metal bond diamonds can be used with all National planetary and passive planetary grinders.

HELIX, 8274-4
9510-50 9510-50 METAL BOND DIAMOND - PROFILING DIAMOND

50 Grit: Prep concrete for polishing. Used for light, medium, and aggressive concrete grinding and profiling as well as sealer and top coat removal. Can be used for both residential and industrial applications. Perfect for leveling concrete high spots and repairing imperfections as well as creating the perfect profile for accepting new coatings and epoxies, or preparing concrete for polishing. Metal bond diamonds can be used with all National planetary and passive planetary grinders.

HELIX, 8274-4
9507-12 9507-12 METAL BOND DIAMOND - HALF BAR

12 Grit: Remove thin epoxy, paint, adhesives and sealers. Used for light, medium, and aggressive concrete grinding and profiling as well as sealer and top coat removal. Can be used for both residential and industrial applications. Perfect for leveling concrete high spots and repairing imperfections as well as creating the perfect profile for accepting new coatings and epoxies, or preparing concrete for polishing. Metal bond diamonds can be used with all National planetary and passive planetary grinders.

HELIX, 8274-4
9508-30 9508-30 METAL BOND DIAMOND - FULL BAR

30 Grit: Remove light sealers. Used for light, medium, and aggressive concrete grinding and profiling as well as sealer and top coat removal. Can be used for both residential and industrial applications. Perfect for leveling concrete high spots and repairing imperfections as well as creating the perfect profile for accepting new coatings and epoxies, or preparing concrete for polishing. Metal bond diamonds can be used with all National planetary and passive planetary grinders.

HELIX, 8274-4
9235-16 9235-16 5-INCH BRAZED DIAMOND

16 Grit: Remove thin epoxy, paint, stain, adhesives, and heavy sealers. Used primarily in industrial applications for medium to aggressive concrete grinding and profiling as well as sealer and top coat removal. Perfect for concrete preparation and restoration prior to concrete polishing. In addition, brazed diamonds effortlessly remove stains and imperfections from exterior wood decking while simultaneously profiling wood for receiving new stains and/or sealers. These polishing pads are for use with all National planetary grinders.

HELIX, 8274-4
9507-16 9507-16 METAL BOND DIAMOND - HALF BAR

16 Grit: Remove thin epoxy, paint, adhesives and sealers. Used for light, medium, and aggressive concrete grinding and profiling as well as sealer and top coat removal. Can be used for both residential and industrial applications. Perfect for leveling concrete high spots and repairing imperfections as well as creating the perfect profile for accepting new coatings and epoxies, or preparing concrete for polishing. Metal bond diamonds can be used with all National planetary and passive planetary grinders.

HELIX, 8274-4
9235-30 9235-30 5-INCH BRAZED DIAMOND

30 Grit: Remove adhesives, heavy and light sealers. Used primarily in industrial applications for medium to aggressive concrete grinding and profiling as well as sealer and top coat removal. Perfect for concrete preparation and restoration prior to concrete polishing. In addition, brazed diamonds effortlessly remove stains and imperfections from exterior wood decking while simultaneously profiling wood for receiving new stains and/or sealers. These polishing pads are for use with all National planetary grinders.

HELIX, 8274-4
9510-120 9510-120 METAL BOND DIAMOND - PROFILING DIAMOND

120 Grit: Prep concrete for polishing. Used for light, medium, and aggressive concrete grinding and profiling as well as sealer and top coat removal. Can be used for both residential and industrial applications. Perfect for leveling concrete high spots and repairing imperfections as well as creating the perfect profile for accepting new coatings and epoxies, or preparing concrete for polishing. Metal bond diamonds can be used with all National planetary and passive planetary grinders.

HELIX, 8274-4
9504-25 9504-25 METAL BOND DIAMOND - SUPER SOFT, SINGLE BAR DIAMOND INSERT

25 Grit: Extremely aggressive coating removal with supersoft matrix for hard concrete or heavy cure and seal treatments, perfect for breaking surface tension. Used for light, medium, and aggressive concrete grinding and profiling as well as sealer and top coat removal. Can be used for both residential and industrial applications. Perfect for leveling concrete high spots and repairing imperfections as well as creating the perfect profile for accepting new coatings and epoxies, or preparing concrete for polishing. Metal bond diamonds can be used with all National planetary and passive planetary grinders.

HELIX, 8274-4
9507-16HB 9507-16HB METAL BOND DIAMOND - HALF BAR

16 Grit: Remove various coatings, and profiles on SOFT concrete only. Used for light, medium, and aggressive concrete grinding and profiling as well as sealer and top coat removal. Can be used for both residential and industrial applications. Perfect for leveling concrete high spots and repairing imperfections as well as creating the perfect profile for accepting new coatings and epoxies, or preparing concrete for polishing. Metal bond diamonds can be used with all National planetary and passive planetary grinders.

HELIX, 8274-4

Polishing Pads

Part # Name Standard Metric Description Fits    
9267-3000 9267-3000 5-INCH POLISHING PAD

3000 Grit: Follow 9267-1500 to create a "mirror" polished concrete. Used for polishing concrete to various finishes and shines. Resin bond. Available in escalating grits. These polishing pads are for use with all National planetary grinders.

HELIX, 8274-4
9267-800 9267-800 5-INCH POLISHING PAD

800 Grit: Follow 9267-400 to create a "shine" polished concrete. Used for polishing concrete to various finishes and shines. Resin bond. Available in escalating grits. These polishing pads are for use with all National planetary grinders.

HELIX, 8274-4
9245 9245 VELCRO ADAPTER

Mounts onto the 9241 quick-change magnetic assembly for using polishihng pads and brazed disks. Three adapters are required. 

8274-4
9267-50 9267-50 5-INCH POLISHING PAD

50 Grit: Achieve a "no reflection" polished concrete. Used for polishing concrete to various finishes and shines. Resin bond. Available in escalating grits. These polishing pads are for use with all National planetary grinders.

HELIX, 8274-4
9267-1500 9267-1500 5-INCH POLISHING PAD

1500 Grit: Follow 9267-800 to create a "high shine" polished concrete. Used for polishing concrete to various finishes and shines. Resin bond. Available in escalating grits. These polishing pads are for use with all National planetary grinders.

HELIX, 8274-4
9267-100 9267-100 5-INCH POLISHING PAD

100 Grit: Follow 9267-50 to create a "little reflection" polished concrete. Used for polishing concrete to various finishes and shines. Resin bond. Available in escalating grits. These polishing pads are for use with all National planetary grinders.

HELIX, 8274-4
9267-200 9267-200 5-INCH POLISHING PAD

200 Grit: Follow 9267-100 to create a "moderate reflection" polished concrete. Used for polishing concrete to various finishes and shines. Resin bond. Available in escalating grits. These polishing pads are for use with all National planetary grinders.

HELIX, 8274-4
9267-400 9267-400 5-INCH POLISHING PAD

400 Grit: Follow 9267-200 to create a "satin reflection" polished concrete. Used for polishing concrete to various finishes and shines. Resin bond. Available in escalating grits. These polishing pads are for use with all National planetary grinders.

HELIX, 8274-4

allParts

Part # Name Standard Metric Description Fits    
9292 9292 FLOATING HEAD ASSEMBLY

Improve machine performance, reach low spots, and level high spots by following surface undulation

8274-4
9241 9241 QUICK-CHANGE MAGNETIC-MOUNT ASSEMBLY

Three assemblies and three 73250 tooling holder mounting screens are required

8274-4
9521 9521 CARBIDES & TOOLING HOLDER

Designed for aggressive concrete stock removal as well as coatings, glues, mastics, and other floor covering adhesives. PCDs and carbides can be used with all National planetary grinder machines. Use to attach the above tooling to National's grinders

HELIX, 8274-4
9550 9550 SCREW

Designed for aggressive concrete stock removal as well as coatings, glues, mastics, and other floor covering adhesives. PCDs and carbides can be used with all National planetary grinder machines. Use to attach tooling to the above holder

HELIX, 8274-4
6280-401B 6280-401B 7/32 T-HANDLE WRENCH

7/32" T-HANDLE WRENCH

8274-4
401882 401882 MORFLEX COUPLERS 8274-4
8270 8270 CONCRETE HARDNESS TESTER

Unlike other mineral hardness testing tools, the 8270 is made of metals and alloys of hardness values equal to 2 through 9 on the Mohs hardness scale, so they can be easily ground to sharp points that will not break off. Set includes 8 points, streak plate for testing color, hardness plates (3.5 and 5.5), magnet for detecting magnetic rock, grindstone to keep points sharp, hardness tables, and instructions, all in a compact wooden case.

HELIX, 8274-4
Lord & James provides critical training for every person working in proximity to our machines, improving safety and efficiency, as well as reducing the risk of machine damage. For additional technical assistance, visit our resource library.