Using Dado Cleanout Bits: 7 Handy Router Techniques
When I started getting serious about woodworking, bigger routers and bigger router bits seemed to be all the rage. Three-horsepower routers were becoming common, and bit manufacturers were introducing larger cutters to match. Some of those panel-raising bits sounded like helicopters when they spun up.
But over time, smaller routers have become some of the most useful tools in the shop. Compact and trim routers are easier to handle, and their 1/4" collets have encouraged bit manufacturers to develop smaller, more specialized cutters.
One of my favorites is the dado cleanout bit.
At first glance, it doesn't look like much. It's a short, straight-cutting router bit with a guide bearing. But a look through Woodsmith's back issues reveals dozens of projects where we've put these bits to work.
And despite the name, cleaning up dadoes is only the beginning. Here are seven ways I use dado cleanout bits for cleaner cuts and more accurate woodworking joinery.
What Is a Dado Cleanout Router Bit?
A dado cleanout bit belongs to the larger family of bearing-guided pattern bits.
Like a traditional pattern bit, it has a bearing near the shank that matches the diameter of the cutting edges. The bearing follows an existing edge or template while the cutters remove material.
What makes a dado cleanout bit different is its compact size.
Most have a 1/4"-diameter shank and a relatively short cutting length. For me, a true dado cleanout bit has cutters no longer than 1/4". Anything longer starts moving into conventional pattern-bit territory.
Cutting diameters typically range from 7/16" to 3/4".
These compact dimensions make dado cleanout bits especially useful in trim routers, although they work just as well in full-size routers.
Pay Attention to the Gap Above the Cutters
One detail I always check when selecting a dado cleanout bit is the gap between the bearing and the cutting edges.
Some bits have a relatively wide gap, while others position the bearing close to the cutters.
I prefer bits with a narrow gap for most cleanout work.
A large gap can allow a thin strip of uncut wood to remain between the bearing and cutters. It can also make it difficult for the bearing to follow the side of an existing shallow dado.
That small design difference can have a big effect on how useful the bit is.
1. Clean Up Dadoes Cut on the Table Saw
Let's start with the job these bits were designed to do.
A stacked dado blade makes quick work of cutting dadoes in plywood and solid wood. But the bottom of the cut isn't always perfectly smooth.
The outside blades may leave shallow scoring marks along the edges, while the chipper blades can produce slight irregularities across the bottom.
A dado cleanout bit solves both problems.
After cutting the dado on the table saw, install the cleanout bit in a handheld router. The bearing follows the side of the existing dado, guiding the cutters along the bottom.
This removes minor ridges and leaves a smooth, flat surface.
Tips for Cleaning Up Dadoes
For this task, I prefer a bit with a cutting length of about 1/8".
The dado should be at least 1/4" deep so the bearing can engage the side without forcing you to cut deeper than intended.
If the dado is shallower, you'll need to use a straightedge or another guide instead.
Choose a bit that's narrower than the dado. This gives the cutter room to work without binding between the sides.
Make one pass with the bearing following one edge of the dado, then return along the opposite edge to clean up the remaining surface.
A dado cleanout bit can also help correct minor variations in depth caused by a slightly bowed panel during the original table saw cut.
2. Rout Shallow Dadoes from Scratch
A dado cleanout bit isn't limited to cleaning up an existing cut. It's also a handy choice for making shallow dadoes with a router.
In my home shop, I use a router for many of the dadoes, grooves, and rabbets I cut.
For smaller projects, the required depth is often 1/4" or less, making a short cleanout bit a natural choice.
To rout a dado, clamp a straightedge to the workpiece and use the bit's bearing to follow it.
The short cutting length provides a rigid cutter that's less prone to deflection, helping produce a consistent dado.
3. Cut Grooves and Rabbets with a Router
Don't let the guide bearing distract you from another important feature of a dado cleanout bit: At its heart, it's a straight-cutting router bit.
That means it works well for many of the same operations as a conventional straight bit.
For example, we use dado cleanout bits to rout grooves in drawer sides for side-mounted drawer guides.
In this situation, I often use a handheld router equipped with an edge guide.
The edge guide controls the position of the groove, so the bit's bearing doesn't need to contact the workpiece.
You can also use these bits to cut shallow rabbets along the edges of a workpiece.
And for smaller parts or repetitive cuts, a router table is often the better choice.
With the fence and bit height set, you can rout multiple matching pieces quickly without having to reposition clamps and guides for every cut.
4. Rout Accurate Hinge Mortises
One of my favorite uses for a dado cleanout bit is cutting hinge mortises.
The short cutters and smooth-cutting bottom edges make these bits ideal for removing material from shallow recesses.
For consistent results, I like to use a shop-made template.
The bearing follows the template while the cutters remove the waste, producing a mortise with a flat bottom and accurately shaped edges.
This technique works especially well when you're installing several identical hinges on cabinet doors or other project parts.
And because the bit is compact, it's easy to control with a trim router.
5. Create Recesses for Cabinet Hardware
Hinges aren't the only hardware that benefits from a precisely routed recess.
Many types of cabinet hardware need to sit flush with the surrounding wood.
Campaign-style drawer pulls, decorative corner brackets, and half-mortise cabinet locks are good examples.
A dado cleanout bit can remove the bulk of the waste while leaving a smooth, flat bottom.
For repeated hardware installations, a template helps keep the recesses consistent.
For a one-time installation, I sometimes prefer to rout the waste freehand, stopping just short of the layout lines.
Then I use a chisel to finish the edges and corners.
The flat bottom left by the router provides a useful reference surface for the chisel.
6. Rout Pockets for Decorative Wood Inlays
Another useful application is routing shallow pockets for decorative inlays.
Whether you're adding a contrasting wood detail to a box lid, cabinet door, or tabletop, a clean, flat recess is important for getting the inlay to sit properly.
A dado cleanout bit removes the waste efficiently and produces a smooth bottom surface.
For irregular shapes or repeated designs, use a template to guide the bearing.
This makes it easier to create consistent recesses that match your inlay pieces.
Just remember that the cutter and bearing are the same diameter, so the bit follows the template without the offset associated with a separate router guide bushing.
7. Establish Clean Baselines for Hand-Cut Joinery
Here's an application you might not expect: using a dado cleanout bit to refine hand-cut dovetails and other joinery.
When cutting dovetails by hand, I start by sawing the sides of the pins and removing most of the waste.
Then I use a dado cleanout bit to establish a smooth, flat baseline.
The bearing follows the existing pin surfaces, helping keep the cutter from removing material beyond the intended joint.
The resulting flat surface provides a reference for the remaining cleanup with a chisel.
This same approach works for other joinery where you need a clean, consistent bottom surface.
For example, you can use it to refine the socket at the top of a table leg that accepts a drawer apron or to clean up the space between double tenons on shelves and dividers.
The important thing is to remove most of the waste first, leaving only a small amount of material for the router to clean up.
Why Dado Cleanout Bits Deserve a Place in Your Router Bit Collection
Specialized router bits can sometimes seem too limited to justify buying.
But dado cleanout bits are an exception.
Their short cutting length, compact size, and bearing-guided design make them useful for far more than their original purpose.
From smoothing dado bottoms and routing shallow grooves to cutting hinge mortises, hardware recesses, and decorative inlays, these little bits have proven themselves on project after project here at Woodsmith.
If you use a trim router regularly, I'd recommend keeping at least one dado cleanout bit in your collection.
It's a small bit that can make a big difference in the accuracy and appearance of your woodworking projects.
Get More from Your Router Bits
A dado cleanout bit is even more useful when paired with a well-made template. From cutting precise hinge mortises to shaping matching parts and creating decorative inlays, router templates open up a world of possibilities.
Learn how to make accurate templates, choose the right pattern and flush-trim bits, and use guide bushings to produce clean, repeatable results.
LEARN MORE ABOUT ROUTER TEMPLATES → Making & Using Router Templates
