Skil 3/8 x 4 In. Carbide Tipped Masonry Drill Bit

Why I reached for this bit

I keep a small rotation of masonry bits for anchors, pilot holes, and the odd “why-is-this-so-hard?” bathroom project. I grabbed the Skil masonry bit (3/8 by 4 inches) because its feature set checks a bunch of practical boxes: a dual-cutting carbide tip, a split point to help with starting accuracy, dual flutes, and a 1/4-inch hex shank that drops straight into an impact driver or a standard chuck. On paper, it promised clean starts, decent chip ejection, and compatibility with the tools I already carry.

Setup and design notes

The heat-treated body and shank immediately feel more robust than bargain-bin masonry bits. The hex shank engages firmly in a three-jaw chuck and, of course, locks in securely in a quick-change impact driver. The split point is unusual for a masonry bit; most standard masonry tips are blunt chisels. Here, the point is ground in a way that does seem to reduce skating on harder surfaces, especially on smoother block and glazed finishes. The bit is labeled clearly, which sounds trivial until you’re crouched on a ladder fishing a 3/8 out of a pouch full of dusty steel.

A quick note on specs that matters in the field:
- Diameter: 3/8 inch
- Length: 4 inches overall, with usable depth that’s fine for most sleeve anchors and tap-in anchors, but not for deep embedments
- Max RPM: 1,500 (don’t ignore this—over-speeding a masonry bit is a fast path to dull carbide)

Test setup and tools

I ran the bit in three tools:
- A corded hammer drill for concrete and block
- A mid-torque cordless hammer drill for brick and mortar joints
- A 1/4-inch hex impact driver for tile and for quick anchor work where percussion wasn’t required

I worked through cured poured concrete, cinder block, clay brick, and ceramic wall tile. I also tried it on a couple of common shop scenarios: hanging shelves into a garage block wall and drilling pilot holes for wedge anchors in a slab.

Concrete and cinder block performance

In hammer mode on a decent corded drill, the bit cuts cleanly in cinder block and standard garage slab concrete. The dual flutes move dust out of the hole well for a 3/8-in diameter; I only needed to pause occasionally to blow out dust on deeper holes. Compared to a generic single-flute bit, I saw less heat buildup and less “squeal” at the bottom of the hole. The tip tracks straight, which is one of the main claims of the split point. I still center-punched the concrete where possible—good habit—but even on a smooth slab, the bit didn’t skate once it kissed the surface.

Speed-wise, keeping the drill under 1,200 RPM in hammer mode felt like the sweet spot. At 1,500 RPM it still cut, but the carbide heated quickly and the blows didn’t feel as efficient. The result was clean, round holes that took plastic anchors snugly. For wedge anchors in the slab, the hole stayed true and I didn’t see funneling at the entry—nice for consistent expansion.

In cinder block, the progress is fast and predictable. The flutes evacuated the crumbly core well; debris didn’t choke the bit even when I pushed steadily. If you spend a lot of time in hollow block, that dual-flute geometry is a plus.

Brick and mortar

In brick, I prefer rotary-only for the first few millimeters to avoid spalling, and then I’ll engage hammer mode. This bit’s point helped keep the start on line, and the edge retention after several holes was better than I expected for a general-purpose masonry bit. It didn’t chip or mushroom at the tip. Mortar joints were no problem; the bit pushed through cleanly without wandering into softer material outside the layout line.

Tile and ceramics

Tile is where technique and material really matter. On ceramic wall tile, the bit did fine with rotary-only, low RPM, and light pressure. I used painter’s tape to reduce skating and a spray bottle to keep the area cool. Starts were manageable thanks to the tip geometry, and once the glaze was pierced, progress was steady.

On harder porcelain or heavily glazed, vitrified tile, this is not the tool I’d pick first. It will work if you’re patient and stay cool, but a diamond-tipped tile bit is going to save time and reduce the risk of cracking. The Skil bit is labeled as suitable for tile, and that’s true for standard ceramic. For porcelain, use diamond.

If you’re thinking about drilling a drainage hole in a glazed ceramic planter, the same rule applies: rotary-only, tape, slow, and keep it cool. But for very hard or thick pots, a diamond solution is more reliable.

Impact driver compatibility

The 1/4-inch hex shank is handy for quick changes and is a legitimate benefit if you’re doing occasional masonry with an impact driver. That said, impact drivers deliver torsional impacts, not forward percussion. In concrete, they will drive this bit slowly—passable for light-duty anchors in softer material—but a hammer drill makes a huge difference in speed and bit life. Where the impact driver shines is in tile (rotary-only) and soft masonry where control matters more than speed.

Concentricity in a hex shank can sometimes be slightly worse than a round shank, but I didn’t see wobble that affected hole roundness. The shank didn’t slip in a three-jaw chuck, which can be an issue with smooth round shanks under high load.

Heat, debris, and bit life

Heat is the enemy of carbide edges in masonry. Keeping speed under the stated 1,500 RPM and using a firm, not aggressive, feed rate paid off. The bit maintained its cutting edge over multiple holes in concrete and block without blueing or tip spalling. The heat-treated shank held up—no twisting or rounding of the hex after repeated high-torque starts.

Dust evacuation is solid for a 3/8 bit, though not miraculous. On deeper holes, I still recommend a quick pecking motion and periodic clearing with compressed air or a blower bulb. Doing so reduces friction, keeps the carbide cooler, and results in more consistent diameter.

Precision and hole quality

The split point does what it claims: it reduces walking on smooth surfaces and keeps the early cut centered. Combined with the bit’s stiffness at 3/8-inch diameter, I saw straight holes that matched their mark without the need to step up from a smaller pilot in most materials. If you need high positional accuracy on glazed surfaces, a pilot with a carbide tile bit still offers extra insurance.

The resulting holes were round and within tolerance for plastic and lead anchors; I didn’t have to ream or “wallow” to fit. Edge breakout at the surface was minimal when I used the rotary-only start technique.

Limitations and caveats

• Not a porcelain specialist: It will cut, but diamond wins on hard, vitrified tile and very hard ceramics.
• Depth: At 4 inches overall, you’re limited in embedment. For deep anchor holes or rebar hits, an SDS-plus system with longer bits is the right move.
• Tool pairing: You can use it in an impact driver, but concrete drilling is significantly faster and kinder to the bit in a hammer drill.

Practical tips

• Mark and dimple your start on concrete; tape your start on tile.
• Run below 1,500 RPM; 800–1,200 RPM in hammer mode is a good target.
• Use rotary-only to start in brittle or glazed materials; switch to hammer once you’re through the surface.
• Clear dust periodically, especially in deeper holes.
• Don’t lean on it—let the carbide do the work to preserve the edge.

Recommendation

I recommend this Skil masonry bit for general-purpose 3/8-inch holes in brick, block, and standard concrete, especially for anchors and pilot holes in everyday installs. It starts accurately, evacuates debris well for its size, and the hex shank is convenient across common tools. Use a hammer drill for best results in concrete, keep the speed modest, and you’ll get clean, true holes with good bit life. If your work leans heavily toward porcelain tile or deep, heavy-duty drilling in structural concrete, pair this with a diamond tile bit or step up to an SDS-plus system. For everything else in the light-to-medium masonry category, this bit is a reliable, no-fuss choice.