Concrete

Edge Grinding Along Walls and Columns

Grinding the last inches along walls and columns with a shrouded hand grinder or a planetary's edge mode, matching the field, and OSHA Table 1 for handheld grinders.

Updated · 3 min read

A planetary grinder can't reach the last few inches at a wall, so the edges get a separate pass with a shrouded hand grinder or a machine with an edge mode. The goal is an edge that matches the field, with the dust captured at the tool.

Silica: OSHA Table 1 for handheld grinders

For handheld grinders (other than mortar removal) using a shroud and vacuum, OSHA requires a dust collector that moves at least 25 cfm per inch of wheel diameter, with a filter of 99% or better efficiency and a cyclonic pre-separator or filter-cleaning mechanism. Indoors, no respirator is required for 4 hours or less per shift, and APF 10 is required above 4 hours. Outdoors, no respirator is required.[1] For a 7" wheel, that's at least 175 cfm. See Silica dust safety.

Before you start

Set up the dust collection first.

  • Match the vacuum to the wheel. Among collectors we sell, the National DL2000 is rated 235 cfm[6], and the Pulse-Bac PRO Series 176 to 311 cfm with HEPA filtration.[7] The Taylor EDC.290 is 130 cfm on one motor and 260 on both[8], so run both motors on a 7" grinder.
  • Check the wheel. Run a new wheel at no load for one minute away from people; a flawed wheel will usually break apart in that time.[2]
  • Use a GFCI if the area is damp, and a 12-gauge cord no longer than 50 ft for a 13 to 16 A tool.[2]
  • Test old coatings or mastic before grinding them. See Cutback adhesive and asbestos ID.

Choose the tool

How much edge there is decides the tool.

Tool Reach Notes
7" hand grinder with an edging shroud To the wall The National 3420's convertible shroud works right up to the edge[2]
Pulse-Bac Dust Grabber on a hand grinder About 1/8" from the wall Captures up to 99% of the dust even at the wall[4]
Pulse-Bac Hum-B edge grinder Along walls, standing upright For concrete, terrazzo, thin-set, mastic and epoxy[9]
National Helix, 8274-4 in edge mode Within 1/8" of the wall The Helix works within 1/8" of the wall from either side of the machine[3]

Step by step (National 3420)

The National 3420 works as a grinder with the shroud closed and an edger with the nose open.[2]

  1. Mount the cup wheel. Use knockout cup wheels, and hand-tighten threaded wheels.[2]
  2. Connect the vacuum to the 2" port and turn it on. Never run a machine designed for a dust collector without one.[2]
  3. For open-floor work, keep the wheel fully inside the shroud; with the vacuum on, the shroud should pull down against the floor.[2]
  4. For edging, lift the shroud nose to expose the cup wheel, set the machine against the wall and grind.[2]
  5. Keep the rubber dust guard down to the floor, and keep the tool moving.
  6. Close the shroud again when you move back into the field.

Match the field

Edges should look and feel like the rest of the floor.

  • Use the same grit sequence at the edge as in the field. Husqvarna's edge grinder takes the same tooling as the main floor grinder[10], and its specification calls for a consistent finish from wall to wall.[5]
  • Check the profile against CSP chips if a coating follows. See ICRI CSP profiles.
  • For bond and grit choice, see Diamond bond and grit selection.

Clean up

OSHA prohibits dry sweeping or dry brushing where it adds to silica exposure, unless wet sweeping or HEPA vacuuming isn't feasible, and restricts compressed air for cleaning.[1] HEPA-vacuum the edges and the floor.

Common mistakes

These cause dust complaints and uneven edges.

  • Undersized vacuum. Check cfm against the wheel diameter.
  • Grinding with the wheel exposed in the field. Only open the shroud at the wall.
  • Locking the trigger. Never lock the handle lever on.[2]
  • Different grits at the edge. The perimeter shows a different profile or sheen.

Tools we carry

These cover edge grinding and dust capture.

Regulations and references

  1. OSHA 1926.1153, Silica, including Table 1
  2. National 3420 hand grinder manual
  3. National Helix manual
  4. Pulse-Bac: Dust Grabber shrouds
  5. Husqvarna: Polished concrete specification
  6. National Flooring Equipment: DL2000 dust collector
  7. Pulse-Bac: PRO Series vacuums
  8. Taylor: EDC.290 dust collector
  9. Pulse-Bac: Edge grinders
  10. Husqvarna: HTC 270 EG edge grinder

Linked PDF documents are archived copies saved by PreFloor Tools so they stay available if the publisher moves or removes them. Check the publisher's website for the latest revision.

Tools for this job

Shop by category

More Concrete guides

Parts for these machines

OEM replacement parts, organized by assembly, with the manual for each machine.