Carpet

Scraper Blade Selection: Width, Angle and Material

Blade width, bevel direction, angle and blade type for each flooring material, plus how to keep blades sharp enough to matter.

Updated · 2 min read

The blade does the work, not the machine. Most slow removals come down to a blade that's too wide, set at the wrong angle, or dull.

Quick answer

Start narrow and go wider only if the material lets you. Run bevel up on concrete and bevel down on wood. Use self-scoring blades for carpet and soft sheet goods, and carbide-tipped shanks for ceramic. Keep a stack of sharp blades on the job.

Width

A narrow blade cuts with less effort than a wide one and usually leaves a cleaner floor. Start narrow, especially on hard-to-remove materials, and widen only as far as the material allows.[2]

  • VCT: never wider than the tile.
  • Rubber tile and sheet vinyl: score to the blade width; around 10" is a common starting point.
  • Glue-down carpet: self-scoring blades, typically 6" to 14".

Bevel up or bevel down

The substrate decides which way the bevel faces.

Bevel up Bevel down
Substrate Concrete Wood, plywood, luan, particleboard
Why Cuts best on concrete, especially when cleaning adhesive[1][2] Glides over the subfloor instead of gouging it
Angle Steeper for hard tear-outs like tile over concrete Set per the machine manual

Blade types

Beyond width and bevel, the type of blade matters for the material you're removing.

  • Standard and heavy-duty: the everyday blade for VCT, adhesive and sheet goods. Extra heavy-duty and high-tempered versions hold up on tougher bonds.
  • Self-scoring: wings on each end cut the material into strips as you go. Best for carpet, carpet tile, cushion-backed and soft sheet goods. Thick carpet may need tall 4" wings.[3]
  • Angle and straight shanks: narrow, thick tooling for tile, wood and hard goods.
  • Carbide-tipped shanks: the go-to tooling for removing ceramic tile reliably.[4]
  • Razor blade cutting heads: thin replaceable blades for cleaning residual adhesive and thin coatings off concrete.

Keeping them sharp

Even the right blade stops working once it's dull, so sharpening is part of the job.

  • Sharpen steel blades with a 4" disk grinder at 120 grit or finer, or better, on a bench or belt grinder in the shop. Remove the whole back-bevel that forms in use.[5]
  • Carbide tips need a silicon carbide (green) wheel.[5]
  • File the wings on self-scoring blades. Dull wings stop scoring and the strips tear.
  • Bring enough sharp blades that nobody sharpens on site.

Common mistakes

Most blade problems come down to width, orientation or a dull edge.

  • Going wide to go fast. A wide blade on a tough bond stalls the machine and leaves more residue.
  • Bevel up on plywood. It gouges the subfloor you're about to install over.
  • Running dull blades. A dull blade slows the machine and stops cutting cleanly.[2]
  • Changing blades with the machine running. Shut it off, drop the head, and wear gloves and glasses.

Blades we carry

These are some of the most-used blades and shanks we carry.

References

  1. National Flooring Equipment: Ride-on tooling guide
  2. National 550 operating manual
  3. National Flooring Equipment: Choosing the best blade for carpet removal
  4. National Flooring Equipment: Ceramic tile removal with a scraper
  5. National 5700 operating and service manual (blade sharpening)

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