How to Cut a Board in Half Thickness (Resaw Method + Kerf Math)
Cutting a board in half by thickness means resawing it — ripping it edge-on into two thinner boards — on a table saw (two flip passes) or a band saw (one pass with a tall fence). A 10″ table saw blade removes about 1/8″ to kerf, while a band saw blade removes as little as 1/32″, so a band saw gets you closer to true half-thickness pieces. This guide covers both methods with real numbers, plus how much thickness you actually lose to the blade.
Table Saw vs Band Saw for Resawing
Both tools can cut a board in half through its thickness, but they behave very differently once the board gets much thicker than about 3 inches.
| Table Saw | Band Saw | |
|---|---|---|
| Typical kerf (material lost) | ~1/8″ (0.125″) | ~1/32″ to 1/16″ (0.030–0.045″) |
| Max resaw thickness | ~3–3.5″ (needs two flipped passes) | 6–12″+ in a single pass, saw-dependent |
| Best for | Stock under 3″ thick, no band saw available | Thicker stock, cleanest and most efficient resaws |
| Main risk | Kickback — tall, narrow offcut can bind and launch | Blade drift — cut wanders off the line without a resaw fence |
Best Thin-Kerf Ripping Blade Pick
Freud LM75R010 10″ Thin Kerf Glue Line Ripping Blade – $58.48
A thin-kerf blade cuts closer to the true 1/32″–1/16″ range instead of the standard 1/8″ full-kerf loss, which matters most when you’re trying to split a board evenly in half on a table saw.
- Best for: table saw resawing where every 1/32″ of thickness matters
- Why we picked it: Freud is an established industrial blade brand and this model is purpose-built for glue-line-quality rip cuts
- Main drawback: thin-kerf blades flex more than full-kerf blades on very hard or thick stock, so feed slowly
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How to Resaw on a Table Saw (Two-Pass Method)
Most consumer table saws max out around 3 to 3.5 inches of blade height, so stock thicker than that needs two passes — cutting halfway from each face.
- Set the blade height to just over half the board’s thickness: for a 1.5″ thick 2×4, raise the blade to about 0.8″.
- Set the rip fence to the board’s centerline: measure from the fence to the near side of the blade, not the far side, so the kerf lands on the waste side of your line.
- Install a tall auxiliary fence and featherboard: the board rides on its edge, so a stock fence and standard featherboards won’t give enough support — this is the step most kickback accidents skip.
- Make the first pass: feed the board through standing on edge, keeping firm downward pressure against the tall fence.
- Flip the board end-for-end and make the second pass: flipping (not rotating) keeps the same face against the fence so the two kerfs meet in the middle.
- Finish the connecting web with a hand saw or band saw if needed: on thicker stock the two passes may not fully meet, leaving a thin center web to finish by hand.
For example, resawing a standard 2×4 (actual 1.5″ thick) on a table saw with a 1/8″ kerf blade leaves about 1.375″ of usable wood, split into two boards around 11/16″ thick before cleanup planing. The same cut on a band saw with a 1/16″ kerf leaves closer to two 23/32″ boards — nearly a full extra 1/32″ per side.
How to Resaw on a Band Saw
A band saw with a resaw fence handles thicker stock in a single pass and wastes far less wood to kerf than a table saw.
- Fit a wide, low-TPI resaw blade: a 1/2″–3/4″ wide blade with 2–3 teeth per inch tracks straighter through thick stock than a narrow general-purpose blade.
- Install a tall resaw fence or shop-made pivot fence: this compensates for blade drift, which is the main reason freehand resaw cuts wander.
- Mark the centerline on the board’s leading edge: a pencil line on the top edge lets you watch and correct drift as you feed.
- Feed at a steady, moderate pace: too fast causes the blade to bow and wander; too slow can burn the cut.
- Support the board as it exits the back of the blade: a roller stand or a helper prevents the two thin halves from tipping and binding right at the end of the cut.
How Much Thickness You Actually Lose to Kerf
📊 A full-kerf 10″ table saw blade removes about 1/8″ (0.125″) of wood as sawdust; a band saw blade removes as little as 1/32″ to 1/16″ (0.030–0.045″). On a 3/4″ board, that’s the difference between two roughly 5/16″ halves off a table saw versus two closer-to-3/8″ halves off a band saw. Always budget for the kerf loss plus a little extra for cleanup planing when you’re calculating “half” thickness. Source: WoodWorkers Guild of America.
| Starting Thickness | Table Saw Result (per side, ~1/8″ kerf) | Band Saw Result (per side, ~1/16″ kerf) |
|---|---|---|
| 3/4″ (0.75″) | ~5/16″ (0.3125″) | ~11/32″ (0.344″) |
| 1″ (1.0″) | ~7/16″ (0.4375″) | ~15/32″ (0.469″) |
| 1.5″ (2×4 actual) | ~11/16″ (0.6875″) | ~23/32″ (0.719″) |
These figures assume the cut lands dead center; plan on losing a little more to cleanup planing afterward since a resawn face is rarely glue-ready straight off the saw.
Common Mistakes and Troubleshooting
- Measuring the fence to the far side of the blade. Always measure to the near side (the side facing the fence) — the kerf itself accounts for roughly 1/8″ you’d otherwise lose track of.
- Skipping the tall auxiliary fence on a table saw. A board standing on edge is unstable against a standard-height fence; this is the single biggest cause of resaw kickback.
- Feeding a band saw too fast. This bows the blade and causes it to drift off the centerline, leaving one half noticeably thicker than the other.
- Forgetting the kerf when planning final dimensions. If you need two boards at a specific finished thickness, add the kerf loss (1/8″ for table saw, up to 1/16″ for band saw) plus planing allowance to your starting stock thickness before you cut.
“A band saw is preferred over a table saw mainly because of thin kerf.”
If you resaw often, a dedicated resaw setup on a band saw — a wide low-TPI blade plus a tall shop-made fence — pays for itself quickly in wasted material saved. Our band saw blade guide covers blade selection in more depth, and if kickback risk on the table saw method concerns you, a table saw gripper adds a second point of control when feeding narrow, tall stock.
Frequently Asked Questions
What is the best way to cut a board’s thickness down on a table saw?
Set the blade to just over half the board’s thickness, rip a pass with the board standing on edge against a tall auxiliary fence, then flip the board end-for-end and rip a second pass so the two kerfs meet in the middle. This two-pass method works for stock up to about 3 to 3.5 inches thick on most table saws.
How do you cut a 3/4 inch thick board in half lengthwise (by thickness)?
On a table saw, resawing 3/4″ stock with a standard 1/8″ kerf blade leaves two pieces around 5/16″ thick each. A band saw with a thinner kerf leaves closer to 11/32″ per side. Either way, a single table saw pass usually reaches full depth on 3/4″ stock, so no flip pass is needed at this thickness.
If I want half of a 2×4’s thickness, where should I set the blade?
A 2×4 is actually 1.5 inches thick, so set the blade height to about 0.8 inches for the first pass, flip the board, and cut again at the same height. Accounting for a 1/8″ table saw kerf, you’ll end up with two boards close to 11/16″ thick rather than an exact 3/4″ each.
How thick is a table saw blade’s kerf?
A standard full-kerf 10″ table saw blade removes about 1/8 inch (0.125″) of wood as sawdust. Thin-kerf table saw blades cut closer to 3/32″ (0.094″), and band saw blades remove as little as 1/32″ to 1/16″ (0.030–0.045″).
Can I resaw a board without a band saw?
Yes. A table saw can resaw stock up to about 3 to 3.5 inches thick using the two-pass flip method described above. For thinner or narrower stock, a hand saw with a scored guide line also works, though staying on the line takes more practice than a fenced power tool cut.
Conclusion
Cutting a board in half by thickness is resawing, and the tool you choose changes how much wood you actually keep: a table saw’s 1/8″ kerf costs noticeably more material than a band saw’s 1/32–1/16″ kerf, especially once you’re flipping for a second pass on thicker stock. Budget for the kerf loss up front, use a tall fence for stability, and plan on a light cleanup pass with a planer before the resawn faces are glue-ready.
