Bosch 4-1/2 in. Type 1A 24-grit metal cutting wheel

Why I reached for this cutting wheel

On jobs where I’m bouncing between lopping off rusty bolts, trimming angle iron, and cleaning up mangled edges, I prefer a wheel that prioritizes stability and predictability over ultrafine cuts. That’s exactly where the Bosch 4-1/2-inch cutting wheel lands. It’s a Type 1A, 24-grit aluminum oxide disc with a 7/8-inch bore and a 3/32-inch thickness, designed for standard small angle grinders. In use, it feels straightforward: a stout, no-frills cutoff wheel intended for general metal cutting and rough removal that doesn’t flex or chatter when the cut gets awkward.

Setup and compatibility

The wheel dropped onto my 4-1/2-inch grinder’s 7/8-inch arbor without drama and locked down with the standard nut. If you’ve ever fought with oddball arbors or proprietary flanges, you know how much of a relief standard fitment is. Being a Type 1A (ISO 41) wheel, it’s flat rather than depressed-center, so I used it with the guard adjusted accordingly. The flat profile is great for straight cuts and for getting closer to surfaces when I need a cleaner cutoff line.

Cutting performance

This is a coarse, 24-grit aluminum oxide wheel, and it behaves like one. The cut is aggressive, especially on mild steel and standard structural profiles like angle and channel. On 1/8- to 1/4-inch stock, it bites in decisively and holds the line without the jumpiness I sometimes get from ultrathin cutoff wheels. It’s not designed to be a finishing tool; think “cut to length now, dress the edge later.” The coarser grit and thicker kerf produce more burr than thin wheels, so plan on a quick pass with a file or a flap disc afterward.

I used it on:
- Mild steel flat bar and angle iron
- Rusted bolts and threaded rod
- Light gauge pipe and EMT

In each case, the wheel tracked predictably and didn’t force me to baby the feed. If your work leans toward utility cutting over delicate sheet metal trimming, you’ll appreciate the confidence it inspires.

Control and cut quality

At 3/32 inch thick (0.09375), the wheel has a more substantial feel than the 0.045-inch “laser” wheels many of us use for speed. The payoff is stability. It resists deflection and side-loading better, letting me keep a straighter line across longer cuts. That makes it easier to avoid binding and far easier to control when cutting uneven, corroded, or painted stock where the kerf wants to wander.

The trade-off is predictable:
- Slightly wider kerf and more material removed per cut
- A bit more heat and sparks
- Rougher edge finish than finer-grit or thinner wheels

For fabrication where the edge will be cleaned or beveled later, none of that is a dealbreaker. For flush, delicate, or cosmetic cuts on thin sheet, I’d switch to a thinner cutoff wheel.

Durability and wear

A thicker, coarse-grit wheel tends to last longer under rough use, and that was my experience here. It handled repeated cuts on mild steel without glazing or chunking out, and the wear rate was consistent. I didn’t baby it—cross cuts, offhand cuts, and a few awkward plunge cuts were all in the mix—and it held together well. If you’re used to going through two or three skinny wheels when tackling a full afternoon of cutting, this wheel’s durability will feel like a welcome shift.

One note: because the wheel is thicker, it tolerates minor twisting better than the ultra-thin discs, but it’s still a cutoff wheel. Keep the pressure in line with the cut and resist the temptation to grind with the face. That habit shortens wheel life and increases the chance of a fracture with any Type 1.

Heat, burrs, and cleanup

The wheel runs warm on thicker stock, as expected. On extended cuts, I found a light, steady feed and periodic pauses kept heat under control and reduced discoloration on the workpiece. Burr formation is noticeable but straightforward to remove. If I needed a cleaner edge on tube or thin stock, switching to a thinner wheel or following with a flap disc was the quickest route.

Sparks were typical of coarse aluminum oxide—plenty of bright spray but nothing excessive. Keep your work area tidy and combustibles out of the spark path.

Where it fits in the kit

I think of this wheel as a dependable generalist—ideal for:
- Shop maintenance and fabrication
- Construction punch lists (demolition cuts, hanger trimming, lopping off fasteners)
- Vehicle and equipment repair where fast, straight cuts matter more than finish
- Cleaning up ragged metal edges before fitting parts

Situations where I’d pick something else:
- Thin sheet metal or delicate work: a 0.040–0.045-inch cutoff wheel
- Stainless or hard alloys where longer life matters: a higher-grade abrasive like zirconia or a ceramic wheel
- Blending and surface prep: a flap disc or Type 27 grinding wheel

Safety and ergonomics

The wheel’s Type 1A profile kept the grinder balanced and easy to aim. With a flat wheel, guard positioning matters; set it to shield sparks and give yourself a clean line of sight. As with any cutoff task, keep a two-handed grip, align the wheel properly, and let the abrasive do the work. The wheel didn’t load up on painted or galvanized stock, but cutting through coatings always benefits from a touch of patience and a steady feed.

Specs that matter

• Diameter: 4.5 inches
• Type: 1A (ISO 41), flat cutoff
• Grit: 24, aluminum oxide
• Thickness: 3/32 inch (0.09375)
• Bore: 7/8 inch
• Pack: 1 wheel
• Model: CW1M450 (order number 2610065821)

In practical terms, those specs translate into a wheel built for stability and toughness on everyday steel cutting, with a coarse grain that prioritizes speed over surface refinement.

Value

Even as a single wheel pack, the durability and control make it a good value for people who do more than occasional cuts. If you measure value by wheels per job rather than wheels per dollar, the thicker profile pays you back—especially if your cutting list includes heavier stock or less-than-perfect material. Pros will likely keep thinner wheels alongside this one for specialty cuts; DIYers could run this as their go-to and add a finer wheel only if they find themselves trimming delicate sheet.

Pros and cons

Pros:
- Stable, predictable tracking thanks to 3/32-inch thickness
- Aggressive cutting on mild steel and general shop metals
- Fits standard 7/8-inch arbors and locking nuts
- Resists deflection and side-load better than ultrathin discs
- Durable under mixed, real-world cutting

Cons:
- Wider kerf and rougher edge than thin cutoff wheels
- More burr formation; usually requires a quick cleanup pass
- Not the best choice for precise, cosmetic cuts on thin materials

Recommendation

I recommend the Bosch 4-1/2-inch cutting wheel for anyone who needs a reliable, general-purpose metal cutoff disc that favors control and durability over ultra-clean, paper-thin kerfs. The 24-grit aluminum oxide bond and 3/32-inch thickness make it a steady performer on everyday steel cutting, demolition tasks, and shop fabrication. It’s not the one wheel to cover every scenario, but it earns its keep as the dependable workhorse you reach for first—especially when the cut is awkward, the stock is stubborn, or you’d rather make one confident pass than nurse a fragile disc through the job.