DeWalt 1-1/2" x 22-1/2" High Impact 4-Cutter Carbide Drill Bit

I put DeWalt’s 1-1/2-in. SDS Max 4-cutter bit to work on a retrofit job that needed a handful of deep penetrations through a 10-inch slab and several 12-inch stem walls. It’s a big, heavy bit—more akin to a small core drill than a typical anchor bit—and it asks a lot of any rotary hammer. After a few days of beating on it in cured concrete and a couple unwelcome encounters with rebar, I’ve got a solid sense of where it shines and where it doesn’t.

Setup and first impressions

The bit locks into an SDS Max chuck with a precise, slop-free fit. The shank machining is clean, and the four-flute helix is consistent along the 18 inches of usable length. The 4-cutter carbide head is broad and symmetrical, with generous carbide land at the corners and a central chisel edge that’s not overly blunt. Overall length is 22-1/2 inches, so you get enough reach for most through-holes without resorting to an extension.

This is not a lightweight: it’s over 5 pounds. In practice, that mass helps the bit carry momentum and stay on line, but it also demands a real SDS Max hammer. I used a 12-amp corded rotary hammer and a high-output cordless model on 60V packs. Both drove it, but the corded tool kept a steadier pace and ran cooler.

Speed and hole quality in concrete

On 4,000–5,000 PSI concrete, the bit’s pace is respectable for its size. It’s never going to be “fast” compared to a smaller diameter, but the 4-cutter head does two important things: it breaks aggregate more evenly, and it keeps the hole round. My holes consistently measured within about 1/16 inch of diameter and stayed straight over the depth, which matters when you’re feeding sleeves or conduit.

I found the bit happiest at a steady, moderate feed pressure. Leaning hard slows it down because you bog the flutes and increase heat at the cutting edges. Let the hammering action do the work, keep the bit plumb, and withdraw every couple of inches to clear dust. With that routine and a decent dust extractor, chip evacuation is good for a bit of this diameter—credit to the four-flute helix, which does a better job pulling fines than a two-flute design.

Rebar encounters

No one plans to hit rebar, but on retrofit, it happens. The head geometry on this bit is clearly designed with steel strikes in mind. I grazed a #4 bar twice and hit it square once. In all cases, the bit didn’t grenade or chip badly. The corners rounded slightly after the square hit, and progress slowed, but it kept cutting concrete immediately after with no wobble or vibration spike. That’s exactly what I expect from a 4-cutter head: reduced snagging, less tendency to lock on steel, and better survivability.

To be clear, I don’t recommend intentionally drilling steel with a concrete bit. If you anticipate cutting through rebar, a dedicated rebar cutter or a core rig is a better plan. But for those unavoidable kisses, this DeWalt holds up.

Vibration, tracking, and user fatigue

For such a large bit, vibration levels are surprisingly manageable. The tool’s weight and balanced head help the bit track cleanly, especially when starting. I like to start at a slight angle to etch a shallow pocket, then stand the tool up to 90 degrees; the 4-cutter head bites predictably and doesn’t skate. Over longer holes, the bit stayed true without wandering—that’s important when you’re trying to come out near a template mark on the far side of a wall.

User fatigue is real with any 1-1/2-in. solid bit. This one doesn’t feel harsher than competitors; if anything, it’s a touch smoother under load than some two-cutter designs. Still, plan your stance, brace the handle, and let the hammer do the work.

Durability and the bonding system

I paid particular attention to the tip-to-flute braze line after the rebar contacts and a few dozen holes. No signs of separation or heat discoloration, and the carbide segments stayed seated. DeWalt’s bonding approach and their fatigue hardening treatment appear to be doing their jobs. Edge wear was present—as expected—but even after the rebar impacts the cutting edges remained intact enough to keep productive. Sharpening a 4-cutter head is possible, but not trivial; I prefer to run them until the corners round past usefulness and then replace.

The manufacturer’s no-break replacement guarantee is nice peace of mind, assuming you meet the terms. It’s not a free pass for abuse, and it won’t cover normal wear, but knowing a catastrophic shank or head failure is backed helps when you’re buying a premium-sized bit.

Depth and chip evacuation

With 18 inches of working length, you can punch cleanly through typical structural members. The four-flute helix genuinely helps here. Debris clears faster than on older two-flute bits I’ve used in this size, and that translates to fewer bind-ups and less heat. I still recommend a dust extractor collar when possible. It keeps the flutes clearing efficiently and improves visibility at the hole mouth, which reduces the temptation to overfeed.

On very sandy mixes or soft block, the bit can self-feed more aggressively. Ease up on the pressure to avoid over-enlarging the hole at entry.

Comparisons and compatibility

Compared to a Bosch SpeedX and a Hilti TE-YX in the same diameter, the DeWalt sits comfortably in the top tier. The Hilti was a hair faster in heavily reinforced slab, and the Bosch felt marginally lighter in the hand. The DeWalt edged both in smoothness and tracked straighter for me on long, blind holes. Price varies by market, but the DeWalt often undercuts the Hilti while landing in the same performance neighborhood, which makes it appealing to crews that go through multiple bits over a project.

Any SDS Max rotary hammer with the torque to spin a 1-1/2-in. bit will pair fine. Corded models in the 12–15-amp range are ideal. High-output cordless will do the job for a handful of holes, but expect battery swaps and slower progress as packs heat up.

What could be better

• Weight: That 5-plus pounds adds up over a day. Not unique to this bit, but worth noting.
• Entry chisel: The central chisel is a little broad; a slightly keener grind might speed starts in very hard aggregate.
• Availability in dust-reduced variants: An integrated dust extraction channel would be welcome for silica compliance on larger diameters, though that typically pushes you toward hollow-core bits.

None of these are deal-breakers, and most are realities of the category.

Tips for best results

• Mark rebar and PT cables where possible. Scan if the stakes are high.
• Use a steady, moderate feed. If the hammer note changes or progress stalls, withdraw and clear chips.
• Keep the bit straight. Side loading shortens life and can oval your hole.
• Consider a pilot. A 1/2-in. pilot hole can help on precision layouts before stepping up to 1-1/2 in.
• Let it cool. Long holes build heat; give the bit a breather between passes.

The bottom line

The DeWalt SDS Max 1-1/2-in. 4-cutter bit is a workhorse for large-diameter holes in concrete and reinforced concrete. It tracks straight, clears debris well for its size, and survives incidental rebar contact without drama. The bonding and fatigue treatment inspire confidence for heavy use, and the overall build quality is what I expect from a German-made bit. It’s not magically fast, and it won’t make a small hammer into a big one, but in the right tool it delivers consistent, predictable results.

Recommendation: I recommend this bit for anyone regularly drilling large holes in structural concrete—mechanical, electrical, and retrofit crews who need reliable performance and durability. If your work involves frequent rebar encounters or you live on cordless hammers, weigh your options; a core rig or smaller diameter sequence might be more efficient. But for straight SDS Max drilling in the 1-1/2-in. class, this DeWalt strikes an excellent balance of speed, survivability, and value.