Fyjbnh 7PCS Angle Grinder Nut Angle Grinder Wrench Kit 5/8-11 Flange Metal Lock Nut for Compatible with Dewalt Milwaukee Makita193465-4 Metabo Bosch Ryobi Black Decker 4.5" 5" Grinder Parts

Why I picked up this grinder nut kit

If you run a few angle grinders in the shop, you know the drill: lock nuts wander off, backing flanges get chewed up, and the spanner wrench is always in the wrong place. I picked up this 7-piece grinder nut kit to standardize a few machines, keep spares on hand, and stop cannibalizing old tools just to keep discs mounted. After several weeks of swapping wheels on 4-1/2", 5", and 7" grinders, I’ve got a clear sense of where this kit shines and where you’ll want to double-check compatibility.

What’s in the kit and first impressions

• One two-pin spanner wrench (approx. 30 mm pin spacing)
• Three outer lock nuts (threaded 5/8"-11)
• Three inner backing flanges (unthreaded, act as spacers/centering plates)

The hardware is carbon steel with a clean, uniform finish. Threads on the lock nuts were crisp out of the package—no gritty feel or burrs. The backing flanges have a raised boss to center standard 7/8" bore wheels (cutoff, grinding, flap), and the faces were machined flat enough that I saw no runout issues on properly seated discs.

The spanner wrench is basic but solid. The pins are straight and tight, and the handle has enough leverage for routine swaps without flexing. It’s not a beefy shop-made wrench, but it’s stout enough for daily use if you aren’t reefing on it.

Fit and compatibility: what worked and what didn’t

This kit is designed around the North American standard 5/8"-11 spindle. On those grinders, the threaded outer nut goes on as expected, and the inner flange slips over the spindle to center the disc. On my 5/8"-11 machines (a mix of 4-1/2" and 5" corded and cordless), the parts seated correctly and clamped discs with no wobble.

Where you can run into trouble is with grinders using metric spindles (M10 or M14) or nonstandard arbor setups:

• Many Makita models—especially older 4-1/2" units—use metric spindles. On one of my older Makitas, this kit didn’t thread on at all. If your manual calls out M10 or M14, this kit won’t fit.
• Some compact 4-1/2" grinders and certain regional models (including European variants) are not 5/8"-11. Again, check your manual or the spindle stamp before buying.
• The spanner wrench’s pin spacing is about 30 mm. It fits the included nuts perfectly and matched a few of my OEM nuts, but not all. That’s normal—there’s no universal standard for the hole spacing on all brands. Expect this wrench to be a companion for this kit’s nuts, not necessarily a replacement for every OEM nut you own.

If your grinders are 5/8"-11, you should be in good shape. If you’re unsure, a quick check: 5/8"-11 is clearly stamped on many spindles and in most manuals. If yours lists M10 or M14, skip this kit.

Setup notes and using the kit

Mounting is straightforward:

1. Cut power or pull the battery.
2. Seat the inner flange on the spindle with the raised boss facing the disc (that boss centers 7/8" bore wheels).
3. Place the wheel. Flip orientation as needed for thin cutoff wheels or thicker grinding wheels—flat side vs. recessed side of the outer nut should match your wheel thickness and manufacturer’s guidance.
4. Thread the outer nut by hand and snug it with the spanner while holding the spindle lock.

A few practical notes from use:
- Don’t overtighten. The friction clamping does the work; you’re just preventing spin. Over-torquing wears the spindle lock and can make the next change a headache.
- The backing flanges in this kit are slightly thicker than a couple of OEM plates I own. On grinders with shorter spindle length, that can reduce thread engagement when you stack thick accessories. I didn’t have a case where it wouldn’t clamp, but on one compact grinder there wasn’t much thread to spare with a cup brush.
- If your wheel has a large hub or is dished, flip the outer nut so the recess faces the hub. The flat side works best for thin cutoffs.
- The inner pieces in this kit are unthreaded backing flanges (not threaded “inner nuts”). That’s by design and is how most 5/8"-11 setups are intended to be used.

Performance under load

With 0.045" cutoff wheels, 5" flap discs, and standard 4-1/2" grinding wheels, the clamping was consistent. I didn’t experience any loosening mid-cut, and disc changes were quick—hand snug plus a gentle tweak with the wrench was all it took. Runout stayed minimal as long as the wheel was properly centered on the boss and free of debris.

I also ran the kit through a few hot sessions on mild steel angle and bar stock. The outer nuts warmed up as expected but didn’t discolor or gall. After cooling, the nuts backed off without seizing. The threads still feel clean. The pins on the wrench stayed tight and haven’t shown any signs of bending.

Build quality and durability

Carbon steel hardware for grinder flanges isn’t glamorous, but that’s what you want here—tough, wear-resistant, and dimensionally consistent. The nut faces didn’t mushroom from routine tightening, and the wrench pins feel more substantial than the ultralight wrenches that ship with some entry-level grinders.

After a few weeks of regular swaps:
- No rounded pin holes on the nuts
- No cross-threading or torn threads
- Minimal imprinting on the flange faces

If you’re frequently changing wheels, I’d still keep a drop of light oil or a dab of anti-seize nearby for the spindle threads, especially if your grinders live in a damp environment. It extends the life of both the spindle and nuts.

What could be better

• Clearer labeling on the spanner spacing would help folks determine if it will fit OEM nuts they already own. It’s around 30 mm, but a stamped marking would be handy.
• A bright color on the wrench wouldn’t hurt; black and bare steel both have a way of disappearing on a busy bench or in a work van.
• A slim-profile outer nut option in the kit would be useful for grinders with short spindles or when using thick hubbed wheels.

None of those are dealbreakers—more nice-to-haves than must-haves.

Who this kit suits

• Pros and hobbyists with multiple 5/8"-11 grinders who want to standardize their hardware
• Shops and classrooms where lock nuts evaporate and you need reliable spares
• Anyone who wants a no-drama replacement for worn or missing OEM flanges and nuts

Who should look elsewhere:
- Owners of grinders with metric spindles (M10 or M14)
- Users of quick-change systems (e.g., proprietary quick-clamp nuts or X-Lock)—this kit won’t replace those workflows

Value

Getting three full sets of flanges (inner + outer) plus a wrench at this price point is strong value. OEM replacements for a single grinder can cost nearly as much as this whole kit, and having multiples means you can kit out several grinders at once and still keep spares. For me, the value isn’t just the price—it’s eliminating downtime when a nut goes missing.

Bottom line and recommendation

This is a straightforward, well-made grinder nut kit built around the 5/8"-11 standard. It clamps reliably, the machining is tidy, and the spanner is robust enough for everyday use. I appreciate having three full sets; it let me bring a couple of orphaned grinders back into rotation and stash extras in the drawer.

I recommend this kit if your grinders use 5/8"-11 spindles and you want dependable, affordable hardware with spares to spare. The only caveat is compatibility: confirm your spindle thread before you buy, and don’t assume the spanner will fit every OEM nut you own. If you’re in the 5/8"-11 camp, it’s a low-cost way to reduce hassle and keep your grinder fleet ready to work.