Best Dado Bit for Plywood (2026)

Specs compared

Specifications are manufacturer rated, as published on each listing and collected 22 October 2026. Where a listing states a figure two ways, the table follows the title and bullets.

Why undersized bits matter for plywood

Plywood is sold in nominal thicknesses that run under the stated size, and three listings here are built around that fact. The Freud 89-650 set includes four bits at 1/4, 3/8, 1/2 and 3/4 inch that the listing says match true plywood thicknesses for tight-fitting joints. The Bosch 84602MC is cut at 23/32 inch, which the listing describes as an undersized diameter made to match the actual thickness of 3/4 inch plywood. The Whiteside 1083A is also 23/32 inch, with the listing saying the diameter is designed to match undersized plywood for accurate dados. The Freud 04-140, by contrast, is a true 3/4 inch straight bit: fine for solid wood, but it will cut a loose groove in undersized 3/4 inch plywood.

Buying guide: best dado bit for plywood

Match the bit to the plywood, not the nominal size

The single most useful fact in these listings is the undersized one. If your project uses 3/4 inch plywood, the 23/32 inch Bosch and Whiteside bits are the direct answer; the Freud 89-650 set covers 1/4 through 3/4 inch plywood with a dedicated bit for each. A standard 3/4 inch straight bit like the Freud 04-140 cuts a groove the plywood swims in. Measure your actual sheet thickness before you buy, and pick the bit that matches the wood, not the label. A caliper reading takes ten seconds and ends the most common dado complaint: a joint that is either sloppy or needs forcing.

Shank size: 1/4 vs 1/2 inch

Three picks use a 1/2 inch shank: the Freud 89-650 set, the Whiteside 1083A and, per the title, the Amana flush trim bit. The Freud 04-140 uses a 1/4 inch shank. A 1/2 inch shank runs with less vibration in a table-mounted router, which is how most dado work gets done; the Whiteside listing calls out reduced vibration from its steel body directly. Less vibration means cleaner groove walls and less tearout on the plywood face. If your router only takes 1/4 inch shanks, the 04-140 is the pick that fits, but a 1/2 inch collet is the better setup for dadoing.

Straight bits vs the set

The Freud 04-140 is a double-flute straight bit in Freud’s TiCo hi-density carbide, listed for clean cuts in solid wood, plywood and composites in CNC, handheld and table-mounted routers. It is a good general bit, but it is one diameter. The 89-650 set gives four diameters with Freud’s Perma-SHIELD non-stick coating, which the listing says reduces heat and pitch build-up, in a wooden shadowbox case. If you build with more than one plywood thickness, the set ends the guessing; if you only ever dado 3/4 inch stock, one 23/32 bit does it.

The flush trim bit is not a dado bit

The Amana 45489-S is included here because the task lists it, but be clear about what it is: a 1/2 inch diameter flush trim bit with an upper ball bearing for template and pattern routing, not for cutting grooves. Its listing names joinery, internal cuts and plywood among its uses, and it is carbide tipped like the rest, but it cannot cut a dado. It belongs in the kit for pattern work; it does not belong in the dado ranking, which is why it sits last.

Contradictions inside the listings

Two listings state a figure two ways. The Whiteside bullets describe a two-flute bit while its spec table says one flute; the title and bullets win, so this is a two-flute bit. The Freud 04-140 bullets list carbide height at 3/4 inch while its spec table lists cutting length at 0.63 inches; again the bullets win. Neither contradiction changes what the bit is, but both are worth knowing before you compare numbers across listings.

How the scores add up

Each bit is scored on performance, build, value, safety listing and warranty, with the weights published on our How We Pick page. A spec the listing does not publish scores nothing; no listing here states a warranty with a concrete term.

Scores run from 9.2 to 9.8: each product’s point total is placed on that range, so more points always means a higher score.

FAQ: lasers and CNC

What size dado bit for 3/4 inch plywood?

23/32 inch. Both the Bosch 84602MC and the Whiteside 1083A are cut at 23/32 inch specifically because 3/4 inch plywood runs undersized, and the Freud 89-650 set includes a 3/4 inch bit the listing says matches true plywood thickness. A true 3/4 inch bit like the Freud 04-140 cuts a loose dado in undersized sheet.

Can I cut dados with a straight router bit?

Yes, with the right diameter. The Freud 04-140 is a straight bit listed for plywood and composites, and any straight bit of the correct undersized diameter cuts a dado. What matters is the diameter match, the 1/2 inch shank for stability, and a router table or edge guide to keep the groove straight. Take the cut in two passes on deep dados rather than hogging it all at once; the bit and the edge both last longer.

What is an undersized plywood bit?

A bit cut slightly under the nominal size to match plywood that runs thin. The Bosch 23/32 inch bit and the Whiteside 23/32 inch bit are the examples here, both described as matching the actual thickness of 3/4 inch plywood. The Freud 89-650 set takes the same idea across four thicknesses: 1/4, 3/8, 1/2 and 3/4 inch.

Is 1/4 inch or 1/2 inch shank better for dados?

1/2 inch, where your router accepts it. The Freud 89-650 set and the Whiteside 1083A both use 1/2 inch shanks, which run truer with less vibration in table-mounted work. The Freud 04-140’s 1/4 inch shank fits compact routers and CNC spindles with small collets.

Can the Amana flush trim bit cut a dado?

No. The Amana 45489-S is a flush trim bit with a pilot bearing for template routing; it trims edges flush to a pattern rather than plunging grooves. It is a fine bit for its job, and plywood is among its listed materials, but it is not a dado bit.

Related: the best rabbet bit for CNC router, best router bit for trim work and the CNC tooling hub.