Floor Sanding Edger Discs 7-Inch: VA vs Norton vs 3M

For most edger work: Virginia Abrasives PSA discs in 36/60/80 grit for the cut passes (open-coat resists clogging); Norton closed-coat at 100 grit for the finishing pass when you’re staining or using water-based polyurethane; 3M as fallback if neither is in stock. Match the edger grit to the drum grit at every stage. Budget 4 to 6 discs per grit for a 200 sq ft room. This guide compares the three brands honestly, walks the PSA-vs-hook-and-loop decision, and gives per-grit picks. For Clarke Super 7R machine setup, see our 7R guide.

Three pre-rental checks

Same as for any floor sanding rental:

1. Engineered vs solid? Check.
2. Pre-1978 house? Lead test first. Why.
3. Two separate 15A circuits? Setup.

Why edger discs matter

Drum sanders cannot reach within 6–12 inches of walls. Without proper edge sanding, a visible line appears around the room perimeter where the wall edge remains unfinished while the center is polished. Two-tone effect, immediately identifiable as amateur work.

For machine setup and technique — including the variable-speed dial that most operators ignore — see our Clarke Super 7R guide.

Machine compatibility

7-inch discs fit:

Machine	Spindle	Notes
Clarke Super 7R (modern)	7/8” center hole	Most common rental edger
Clarke Super 7R (older)	5/16” center hole	Verify spindle before buying
Hiretech HT7	7/8” center hole	Same disc size
Other 7-inch orbital edgers	varies	Check the machine before ordering

Confirm spindle size before purchase. Wrong center hole = wasted trip to the supplier.

Honest cross-brand comparison

Brand	Coat	Best grit range	Disc life vs baseline	Price tier	Honest verdict
Virginia Abrasives	Semi-closed	36–80 (cut grits)	Baseline (1×)	$	Best for the first cut. Semi-closed coat resists loading on old finishes. Contractor default for cut passes.
Norton	Closed	80–120 (finishing)	1.3–1.5× VA on hardwoods	$$$	Finer scratch pattern at 100/120 — matters under water-based poly and stain. Worth the upgrade for finish grit only.
3M	Closed	All grits	1.1–1.2× VA	$$	Middle ground; nobody’s first pick. Default if neither VA nor Norton is in stock.

The honest take: VA wins for cut grits, Norton wins for finish grits, 3M is the fallback. Mix brands by stage for the best result at the lowest total cost.

Picks by user mode

Your situation	Cut grits (36, 60, 80)	Finishing grit (100)	Where to buy
One floor, one weekend, oil-based clear	VA PSA across the board	Skip 100 — finish at 80	VA 36 · VA 60
One floor, one weekend, water-based or stain	VA PSA all three	Norton closed-coat 100	VA Amazon + Norton 7” search
Light pro doing 3–6 floors a year	VA hook-and-loop (faster disc changes save 5–10 min per change)	Norton hook-and-loop closed-coat at 100	VA hook-and-loop search + Norton search
Hard species (hickory, jatoba, hard maple)	Virginia Abrasives Monster ceramic discs (or Norton SG / 3M Cubitron)	Monster ceramic	VA Monster line · VA store

The Norton links carry the same affiliate tag as ours — we earn the same small commission whichever brand you pick, so the picks are by fit, not payout. The Monster line link goes to the manufacturer’s site and earns us nothing.

PSA vs hook-and-loop — the format decision

PSA (pressure-sensitive adhesive)

• Adhesive backing sticks directly to a metal backing plate
• ~$2–4 per disc at loose-disc retail; VA’s 50-disc contractor boxes pencil under a dollar a disc (the 36-grit box runs ~$48). Either way, 20–30% cheaper than hook-and-loop
• 5–10 minutes per disc change (clean old adhesive, install new, wait for set)
• Adhesive cleanup required between grit changes
• Industry standard at rental shops — most rental 7Rs ship PSA-ready

Hook-and-loop (Velcro-style)

• Velcro-like backing on a hook-and-loop pad
• ~$3–5 per disc, but the pad itself is ~$10–20 one-time cost
• 30 seconds per disc change
• No adhesive cleanup
• Pads last indefinitely; discs reuse cleanly for next-grit work

Which should you buy

For a typical refinish with 3–4 grit passes — hook-and-loop is worth it. You change discs at least 6–8 times. The 5–10 minute time savings per change adds up to 30–80 minutes per job.

For a single-grit screening pass, PSA is fine.

Pro tip: ask the rental shop if their 7R is hook-and-loop ready, or if they can install a hook-and-loop pad for a small fee. Most do this now.

Why semi-closed/open coat for cut grits and closed for finish

Cut grits 36, 60, 80 — semi-closed or open coat

Open-coat discs cover ~60% of the backing with grit and leave dust-clearance gaps; semi-closed coat sits just below fully closed but keeps enough gap to resist loading. On old polyurethane or any gummy material, that clearance lets dust fall away instead of welding into the abrasive — a loading-resistant disc at 36 grit on a finished floor lasts far longer than a fully closed-coat disc at the same grit.

VA’s floor line is semi-closed coat — VA credits the semi-closed coating with resisting loading from old coatings, which covers the cut grits well. This is where VA earns its contractor-default reputation.

Closed coat at 100/120

Closed-coat discs pack 90–100% grit coverage. More grain = more cutting per pass on dense, clean materials. On bare wood at the finishing stage (no finish loading the disc), closed-coat geometry cuts a more uniform scratch pattern.

Under water-based polyurethane — which is transparent — the more uniform scratch pattern reads as a smoother perimeter. For stain work, uniform scratches absorb stain more evenly and reduce blotchy edges where the edger ran.

Norton’s closed-coat 100 grit is denser and more consistent than VA’s. Worth the upgrade for the final pass when finish quality matters.

Disc quantity per grit

Room size	36 grit	60 grit	80 grit	100 grit
250 sq ft	2–3	2–3	2–3	1–2
400 sq ft	3–4	3–4	3–4	2–3
600 sq ft	5–6	5–6	5–6	3–4

Edger discs wear faster than drum sheets because the 7R operates at high pressure and the smaller disc traces every corner. Budget generously. You can reuse hook-and-loop discs at the next-grit level if they’re not fully worn.

VA’s 36- and 60-grit listings are 50-disc boxes — far more than one job needs, but per-disc cost beats loose-disc retail several times over and the spares carry to the next floor; the 100-grit sells as single discs (~$2 each): 36 grit · 60 grit · 100 grit.

For the full sheet calculator with species multipliers and worked examples, see our sheet calculator.

Common mistakes

Not matching edger grit to drum grit

If the drum just ran 80 grit on the field, the edger needs to run 80 on the perimeter at the same time. Mismatching = visible color and scratch difference at the wall edge under finish.

Tilting the disc

The disc must stay flat against the floor. Tilting creates swirl marks. The most common technique failure on the 7R.

Over-pressing at the wall

The 7R is heavy enough; let it work. Pressing harder doesn’t cut faster — it just gouges the floor edge and tears discs.

Skipping inside corners

The 7-inch disc can’t reach a 90° angle. After the edger pass, hand-sand inside corners with a sanding block at matching grit. 15 minutes per room. Transforms the final appearance.

Worn discs left in service

A worn disc doesn’t cut; it burnishes. Burnished spots reject stain and create blotches. Replace discs when they stop cutting aggressively.

Current prices

Prices pulled from Amazon at publish; verify before ordering. Amazon Associate disclosure: we earn from qualifying purchases.

For machine setup, variable speed, and technique

This article covers the discs. For Clarke Super 7R machine specifics — center hole sizing, variable-speed RPM by grit, rental inspection, edging technique — see our Super 7R machine guide. For the full process see how to sand hardwood floors.

Match the edger grit to the drum grit at every stage. Run light pressure. Keep moving. The disc does the work — your job is not to fight it.

Matt.