DeWalt Hole saw (4 in / 102 mm)

First impressions and setup

I put the 4-inch DeWalt hole saw to work across a handful of jobs: HVAC rough-ins through 2x framing, a couple of plywood cutouts for recessed junction boxes, and a test pass in thin sheet metal and PVC. Out of the clamshell, the cup looks the part—yellow enamel, cleanly formed gullets, and a generous ejection slot that runs nearly the full height of the cup. It’s a bi‑metal body with a high‑speed steel tooth line, so I expected a good balance of toughness and edge retention.

This cup doesn’t ship with an arbor, so I paired it with a standard quick‑change arbor and a 1/4-inch pilot bit. The minimum chuck size is 1/4 inch; I’d strongly recommend a drill with a side handle and low gear. A 4-inch hole saw loads a drill heavily, and the torque spikes when the teeth first bite and again as the plug breaks free.

Cutting performance in wood

The deeper cup is the right idea here. At 1.75 inches of cutting depth, it clears nominal 2-by lumber in one pass, and that makes layout and control simpler. In dry SPF 2x stock at low speed on a mid‑torque drill, the saw started cleanly, tracked the pilot without wandering, and moved chips efficiently. I found the tooth geometry does shed sawdust better than older bi‑metal cups I’ve used; it didn’t pack up nearly as quickly, even in resinous pine.

Cut speed is respectable. I could complete a through-cut in a 2x4 in roughly 12–18 seconds with steady feed. Tearout on the exit side was moderate with no backer and minimal with a backer board clamped in place. In plywood, the cut was smoother than expected for a coarse-tooth cup, particularly when I scored the veneer with a utility knife first. A backer is still the best insurance against splintering.

The ejection slot earns its keep. With dry lumber, I could hook a flat screwdriver behind the plug and lever it out in seconds. In damp material, plugs still wanted to wedge near the pilot, but the continuous slot makes it possible to pry from multiple angles without mangling the teeth.

Metal and plastic

In 20‑gauge mild steel, the saw will do the job if you treat it like a metalworking tool: slow speed, steady pressure, and cutting fluid. I ran around 150–200 RPM on a drill press, applied light oil, and got a clean circle with a thin burr that broke off with a deburring tool. Heat discoloration on the teeth was minimal after a pair of cuts. In thicker steel you’ll want carbide or a knockout punch; bi‑metal is a compromise here.

In PVC and ABS, control your speed. At high RPM the plastic starts to melt, welds to the kerf, and binds. With the drill set to low and a cautious feed rate, I got a crisp edge and a round plug that released easily.

Accuracy and concentricity

This is where my experience diverged from the promising start. Precision matters with a 4-inch cutter. A lot of components that “say” 4 inches—like vent hoods, duct couplers, and some recessed fixtures—expect a tight fit. Using a dial indicator on the rim, my sample showed noticeable runout even with a true arbor and pilot: enough that the tooth path swept a circle larger than the nominal 4 inches. Measured in 3/4-inch plywood, the hole came in at roughly 4.16 inches on the long axis.

In practical terms, that means press-fit parts that expect a 4.00–4.03 inch opening will be loose. On framed penetrations that get trimmed or taped, the oversize isn’t a showstopper; sealant, tape, or a flange hides the slop. But on finish work where the edge must capture a grille or grommet without a flange, that extra sixteenth to an eighth ruins the fit.

To rule out setup errors, I tested in a drill press with a new arbor and pilot, checked the cup for wobble, and clocked the same behavior: the cut tracked the pilot, but the cup’s effective cutting path was eccentric. I could feel it in the handle as a rhythmic pulse when cutting; you see it as a scalloped kerf rather than a perfectly circular scribe.

Chip evacuation and plug ejection

Credit where it’s due: chip evacuation is a bright spot. The tooth geometry and gullet spacing clear sawdust effectively, which keeps heat down and reduces burning in wood. I didn’t need to peck drill; a steady feed kept the teeth cutting rather than rubbing.

The continuous ejection slot is equally helpful. On a deep cup like this, plugs can jam tight; being able to attack from multiple angles without fishing around holes is a real improvement. With metal or plastic plugs, a twist with needle‑nose pliers and a pry with a flat bar got them moving without drama.

Durability and heat

After a dozen holes in 2x material and plywood, plus a couple of metal and plastic tests, the teeth still felt sharp and tracked well in wood. Bi‑metal HSS is proven for this kind of mixed use. There’s some light enamel scuffing and a faint blueing at the tooth tips from the steel cuts, but nothing that hurt performance in wood afterward. As with any hole saw, if you plan a lot of metal work at this diameter, step to carbide-tipped or slow the process way down and flood with oil.

Usability notes and tips

• Use low gear and a side handle. The torque is real at 4 inches.
• Start square. Let the pilot establish, then bring the teeth gently into contact to avoid a wandering kerf.
• Back the cut. A sacrificial board all but eliminates exit blowout in plywood and finish-grade surfaces.
• In metal, slow way down and use cutting fluid. In plastic, control heat with low RPM and light pressure.
• Expect plugs to need persuasion in wet lumber; the continuous slot helps, but a thin pry tool speeds it up.

Quality control and value

Functionally, the design hits several marks: one‑pass depth for 2-by material, strong chip evacuation, and easy plug removal. But the core job of a 4-inch hole saw is to cut a clean, round, appropriately sized 4-inch hole. The runout I observed undermines that. If this were an isolated defect, an exchange would solve it. As a buyer, though, you don’t have a safety net here—this model isn’t covered by a limited warranty—so you’re relying on the retailer’s return policy if you draw a bad cup.

Price will determine how much tolerance you have for swapping a dud, but given the stakes on precise openings, I expect better concentricity out of the box.

Who it’s for

• Good fit: rough-in carpentry, holes hidden by a flange or trim, general construction where ±1/8 inch isn’t a concern, mixed-material one-off cuts.
• Poor fit: press-fit components that require a true 4.00-inch opening, any application where an oversized or slightly elliptical hole is unacceptable.

Bottom line and recommendation

I like several aspects of this 4-inch DeWalt hole saw: it clears 2-by lumber in one pass, evacuates chips well, and the ejection slot makes plug removal painless. In ordinary framing and rough-in work, it powers through quickly and leaves a clean enough hole to cover with a flange or trim ring.

However, the sample I used cut oversized and showed noticeable eccentricity even with a true arbor and pilot. For many users, that won’t matter; for anyone relying on a snug, correctly sized 4.00-inch hole, it absolutely will. Compounding that, there’s no limited warranty on this model to soften the blow if you get a cup that isn’t concentric.

Recommendation: I don’t recommend this 4-inch hole saw for precision 4.00-inch holes or press-fit applications; the runout and oversize cuts are too risky. If your work is rough-in and the hole will be hidden by a flange, it’s serviceable, but I’d still test on scrap first to confirm your cut size before committing on finished surfaces.