Can a 7-1/4 Inch Blade Cut a 4×4? (Real Depth Limit)
A 7-1/4 inch circular saw blade cannot cut through a 4×4 post in a single 90-degree pass — its typical depth of cut tops out around 2-1/2 inches, well short of a 4×4’s actual 3.5-inch thickness. Forcing it through in one pass just binds the blade and risks kickback. This guide covers the real depth-of-cut numbers across common blade sizes, the flip-cut and stop-cut techniques that finish the job, and when a 6×6 post needs a different approach.
Quick Answer
No — not in a single pass. A 7-1/4 inch circular saw blade has a maximum depth of cut around 2-1/2 inches at 90 degrees, while a 4×4 post actually measures 3.5 inches thick. Cut from both sides using the flip-cut or stop-cut method to get a clean, complete cut through the post.
Real Depth-of-Cut: Blade Size vs. Post Thickness
Blade diameter alone doesn’t tell you whether a cut is possible — depth of cut at 90 degrees (and at a 45-degree bevel) is what actually matters against a post’s real thickness. A 4×4 measures 3.5 inches thick, not 4; a 6×6 measures 5.5 inches, not 6. Here’s how the common circular saw blade sizes compare, using typical published depth-of-cut specs:
| Blade Diameter | Max Depth @ 90° | Max Depth @ 45° Bevel | Single-Pass Through 4×4 (3.5″)? | Two-Sided Flip-Cut Total |
|---|---|---|---|---|
| 6-1/2 in. | 2-1/8 in. | 1-5/8 in. | No | 4-1/4 in. — clears a 4×4, falls short of a 6×6 |
| 7-1/4 in. | 2-1/2 in. | 1-7/8 in. | No | 5 in. — clears a 4×4, falls just short of a 6×6 |
| 8-1/4 in. (worm-drive) | 2-15/16 in. | 2-3/16 in. | No | 5-7/8 in. — clears both a 4×4 and a 6×6 with margin |
Depth of cut varies slightly by saw model — check your saw’s spec sheet for the exact figure. No standard circular saw blade cuts through a 4×4 in one pass at 90 degrees; the flip-cut and stop-cut methods below solve that with two cuts from opposite sides.
Why a Single Pass Falls Short
The cutting capacity of any circular saw blade is set by its diameter — roughly a third of the blade’s diameter is unusable (it’s taken up by the arbor and the saw shoe), which is why a 7-1/4 inch blade only reaches about 2-1/2 inches deep instead of 3.625 inches. Against a 4×4’s actual 3.5-inch thickness, that leaves the blade about an inch short. The blade isn’t underpowered or the wrong choice — it’s a normal depth limitation shared by every 7-1/4 inch circular saw on the market, corded or cordless.
This is also why a 7-1/4 inch blade cuts a 2×4 in one clean pass without issue — a 2×4’s 1.5-inch thickness is well inside the blade’s 2-1/2-inch depth. The moment the stock gets as thick as a 4×4, the same saw needs a different approach: cutting from both sides.
How to Cut a 4×4 With a 7-1/4 Inch Blade (Two Methods)
Both methods below use the same principle — cut as deep as the blade reaches on one face, then finish from the opposite face — but they set up the cut differently. See our full walkthrough on cutting a 4×4 with a circular saw for jig and clamping setup photos alongside these steps.
Method 1: The Flip-Cut
- Mark all four faces: Wrap masking tape around the 4×4 at the cut line and mark a square line on all four sides with a speed square so the mark lines up after you flip the post.
- Set the blade to max depth: Adjust the circular saw so the blade extends about 1/8 inch past the post’s far face for a clean exit cut.
- Cut the first face: Guide the saw along the marked line, cutting as deep as the blade reaches.
- Flip and realign: Rotate the 4×4 180 degrees onto the opposite face and line the blade up exactly with the mark and the first kerf.
- Finish the cut: Cut through the second face until the two kerfs meet and the piece separates.
Method 2: The Stop-Cut
The stop-cut sets the blade deeper up front so only one flip is needed, and many find it faster once the depth is dialed in correctly.
- Set a half-plus depth: Adjust the blade to slightly more than half the post’s thickness — about 2 inches for a 4×4.
- Cut past center: Follow the marked line on one face until you’re slightly past the post’s center.
- Rotate 180 degrees: Turn the post over and align the same marked line on the opposite face.
- Meet the kerfs: Cut down until the second kerf meets the first so the post separates cleanly.
For a 6×6 post, neither method alone reliably finishes the cut with a 7-1/4 inch blade — the combined 5-inch depth from two passes falls just short of the 6×6’s 5.5-inch thickness. Plan on finishing the last fraction of an inch with a hand saw or reciprocating saw, or step up to an 8-1/4 inch worm-drive saw if you cut 6×6 posts often.
📊 A 7-1/4 inch blade loses roughly 1/2 to 5/8 inch of depth when the saw is set to a 45-degree bevel versus a square 90-degree cut — factor that in before attempting an angled flip-cut on a 4×4. Source: published depth-of-cut specs for standard 7-1/4 in. circular saw blades (Diablo, DeWalt, Makita).
Does Blade Size Matter for a 4×4?
A 7-1/4 inch blade is the standard size on most full-size circular saws, and its 2-1/2-inch depth of cut is enough to clear a 4×4 in two passes with margin to spare. A 6-1/2 inch blade — common on compact and cordless saws — still works with the same flip-cut or stop-cut technique, just with a smaller margin (2-1/8 inches per pass instead of 2-1/2). See our 6-1/2 inch vs. 7-1/4 inch circular saw comparison if you’re choosing between the two for general use.
If you’d rather avoid the two-sided cut altogether, a 10-inch miter saw or table saw has enough crosscut capacity for a 4×4 in a single pass on most models — though the exact spec varies by saw. We break down the real numbers in whether a 10-inch miter saw can cut a 4×4 in one pass, including which saws fall short the same way a 7-1/4 inch circular saw does.
“The mistake I see most often in the shop is someone trying to muscle a 7-1/4 inch blade all the way through a 4×4 in one pass — the saw bogs down and the cut wanders. Flip the post, match your first kerf, and the second cut finishes clean every time.”
Safety Measures and Considerations
Cutting a 4×4 with a 7-1/4 inch blade means two passes instead of one, which doubles the exposure to the main hazards of circular saw work: kickback, blade contact, and flying debris. The gear and precautions below matter more here than on a single-pass cut.
Potential Hazards
- Injury from contact with the rotating blade, especially during the second (flip) pass when your grip and stance change.
- Kickback, where the saw suddenly moves back toward the operator if the blade binds.
- Flying wood chips or debris, more of it than a single-pass cut produces.
- Electrical shock if using a corded saw near damp lumber or a wet work surface.
Safety Gear and Precautions
- Eye and ear protection: Safety goggles or a face shield, plus earplugs or earmuffs.
- Gloves: Heavy-duty work gloves for grip and hand protection when repositioning the post between passes.
- Respiratory protection: A dust mask or respirator — two passes generate more sawdust than one.
- Appropriate clothing: No loose sleeves, jewelry, or drawstrings that could catch the blade.
- Stable work surface: Clamp the 4×4 to sawhorses so it can’t shift, especially right before the kerfs meet.
- Blade guard and condition: Confirm the blade guard moves freely and the blade itself is sharp and free of pitch buildup before starting.
- Manufacturer instructions: Check your saw’s manual for its specific maximum depth of cut and bevel-angle depth chart.
Choosing the Right Blade for 4×4 Cuts
A carbide-tipped blade with 24 to 40 teeth is the right general-purpose choice for cutting 4×4 posts — fewer teeth (24) cut faster through thick, dense stock, while more teeth (40+) leave a smoother edge at a slightly slower feed rate. High-speed steel blades are cheaper but dull quickly in pressure-treated lumber and aren’t worth using for repeated 4×4 work.
- Slow and steady: A rushed feed rate is the most common cause of a bound or wandering blade on the second pass.
- Support the workpiece: Clamp the 4×4 to sawhorses on both sides of the cut line before starting either pass.
- Re-check alignment after flipping: The single biggest cause of an offset, uneven cut is not lining the blade up with the first kerf precisely after the flip.
For more on matching blades and cutting angles to the job, see our full wood cutting guides.
Frequently Asked Questions
How deep can a 7-1/4 inch circular saw actually cut?
A 7-1/4 inch circular saw blade typically cuts up to about 2-1/2 inches deep at a 90-degree angle, dropping to roughly 1-7/8 inches at a 45-degree bevel. That’s short of a 4×4’s full 3.5-inch thickness, so a single pass won’t cut all the way through.
Can a 6-1/2 inch blade cut a 4×4?
Yes, using the same flip-cut or stop-cut technique as a 7-1/4 inch blade. A 6-1/2 inch blade tops out around 2-1/8 inches deep at 90 degrees, so it also needs two cuts from opposite sides to get through a 4×4’s 3.5-inch thickness.
What’s the difference between the flip-cut and the stop-cut method?
The flip-cut cuts as deep as the blade allows on one face, then flips the post 180 degrees to finish from the opposite face. The stop-cut sets the blade to slightly more than half the post’s thickness up front and finishes with a single flip, meeting the two kerfs in the middle — often faster, but it requires more careful depth-setting.
Why won’t my circular saw cut all the way through a 4×4?
Because no standard circular saw blade — 6-1/2 inch or 7-1/4 inch — has enough depth of cut to clear a 4×4’s actual 3.5-inch thickness in one pass. This isn’t a sign anything is wrong with the saw; it’s a normal depth limitation that the flip-cut or stop-cut method solves.
Can a 7-1/4 inch blade cut through a 6×6 post?
Not cleanly with two passes alone. A 7-1/4 inch blade’s two flip-cut passes total about 5 inches of combined depth, just short of a 6×6’s 5.5-inch thickness. Plan on finishing the last fraction of an inch with a reciprocating saw or hand saw, or step up to an 8-1/4 inch worm-drive saw for a 6×6.
What blade should I use to cut a 4×4?
A carbide-tipped blade with 24 to 40 teeth handles 4×4 crosscuts well — fewer teeth cut faster through thick stock, while more teeth leave a smoother edge. Avoid high-speed steel blades for repeated 4×4 work; they dull faster in pressure-treated lumber.
Conclusion
A 7-1/4 inch circular saw blade will get through a 4×4, just not in one pass — its 2-1/2-inch depth of cut is about an inch short of the post’s real 3.5-inch thickness. Mark all four faces, cut as deep as the blade reaches, then flip the post and finish from the opposite side using the flip-cut or stop-cut method. For a 6×6 post, budget for a hand-saw finish or a larger worm-drive saw, since two passes of a 7-1/4 inch blade land just short of the full 5.5-inch thickness.
