When woodworking, one of the most common joinery techniques is the dado joint. A dado is a groove cut into the surface of a piece of wood that allows another board to be slotted into it to form a strong 90 degree joint. Dados allow two boards to be joined together in a “T” shape. They are typically used in bookshelves, cabinets, drawer dividers, and many other applications where you need a sturdy joint at a 90 degree angle.
To cut a dado, you need a router and a special type of bit called a dado blade. But with so many options on the market, how do you know which router bit is the best for cutting dados? There are a few factors to consider when choosing a dado blade for your router:
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Straight vs Stacked Dado Sets
The two main types of dado blade sets are straight and stacked. Straight dado sets consist of a single saw blade that makes one pass to cut the dado. Stacked dado sets contain multiple thinner blades that are sandwiched together to allow you to adjust the width of the dado.
Straight dado sets are good for common dado widths and tend to leave a cleaner cut since there is only one blade. However, you need a separate straight bit for each width of dado you want to cut.
Stacked dado sets are more versatile since you can use chippers and shims to customize the width. This allows you to use one set to make dados of different widths. The main downside is that the multiple blades can leave more ridges in the cut that may require extra sanding/cleanup.
So if you only need a couple common dado sizes, straight dado sets are likely the simpler and more cost effective option. But stacked dado blades are a good choice if you need to vary the dado width for different projects and applications.
Carbide vs High Speed Steel
Dado blades are also available in both carbide-tipped and high-speed steel (HSS).
Carbide tips last significantly longer than HSS and stay sharper for cleaner cuts. They are more durable against heat buildup and abrasive woods with a lot of resin. However, carbide dado sets are substantially more expensive.
HSS dado blades are a more budget-friendly option. But they will require sharpening more frequently and may wear faster when cutting harder woods. The cut quality tends to degrade sooner as the HSS blades dull.
For most hobbyists doing occasional home projects, a quality HSS dado set will be sufficient. But for professional woodworkers or anyone doing frequent dado cuts, carbide is worth the extra investment for extended blade life and consistent cut quality.
6″ vs 8″ Dado Sets
When choosing a dado set, you also need to consider the diameter – typically either 6″ or 8″. This needs to match the arbor size your router accepts.
6″ and 8″ dado sets both have pros and cons:
– 6″ dado blades are lighter and put less load on the motor. This makes them better for underpowered routers or handheld use. But the narrower width limits the maximum dado size you can cut in a single pass.
– 8″ dado sets allow you to cut wider dados in one pass. But they require a more powerful router motor to drive the larger 8″ blades. And the heavier weight strains some compact routers.
In general, if using a router table with a stationary motor, an 8″ stacked dado set is recommended to handle the widest dado cuts. For handheld use, 6″ is often preferred for better control and less wear on the motor.
Best Router Bits for Cutting Dados
Based on the factors above, here are some of the top options to consider when shopping for the best router bit to cut dados:
Freud SD208 8-Inch Professional Dado
For cutting dados with a router table, the Freud SD208 is an excellent 8″ stacked dado set. It includes an 8″ outside blade, 1/8″ chipper, and adjustable shims to custom fit dado widths from 1/4″ to 29/32″.
The C4 micrograin carbide tips stay sharper longer even when cutting abrasive wood types. PermaShield non-stick coating helps reduce gumming and resin buildup. This professional grade set makes smooth, tear-out free dados across many common widths.
DeWalt DW7670 6-Inch Dado Set
The DeWalt DW7670 is a very popular 6″ stacked dado set for portable and handheld routing applications. The set includes a 6″ outer blade, two chippers, and shims that allow adjusting the width from 1/4″ to 13/16″.
The carbide cutters provide excellent durability and cut performance. At only 6″, this dado set is lightweight and won’t overload a compact router motor. It’s ideal for general home and hobbyist projects.
Freud SD206 6-Inch Professional Dado
Another good 6″ option is the Freud SD206 stacked dado set. Like the DW7670, it includes an outside blade, two chippers, and shims for cutting 1/4″ to 13/16″ width dados.
The TiCo Hi-Density carbide cutters ensure a smooth, precise dado in even the hardest woods with minimal splintering. It’s specially designed to withstand the high RPM of router motors. And the PermaShield coating provides non-stick lubrication.
Forrest Dado King Set
Forrest is known for top-notch router bits and blades, and the Dado King set has excellent reviews from woodworkers. It features a 6″ outer blade and two chippers for adjustable width dados.
What makes the Forrest Dado King stand out is that it uses a specially formulated C3 micro-grain carbide that stays sharper longer. This provides ultra-smooth dado cuts in both soft and hard woods with minimal chipping. It’s also designed to withstand high RPM speeds.
Whiteside Router Bits 413
The Whiteside 413 is a very affordable 6″ stacked dado set. Despite the lower price, it provides good quality thanks to the carbide cutters.
The set includes an outer blade, two chippers, and shims for 1/4″ to 13/16″ width dados. The cutters have U-shaped gullets to efficiently direct sawdust out of the dado channel. For budget-minded woodworkers, the Whiteside 413 performs well above its price.
How to Use a Dado Set
Once you’ve selected the right router and dado set, proper technique is also important to get clean results. Here are some tips for using a dado set correctly in a router:
– Make multiple light passes rather than trying to remove too much material in one pass. Go slow and gradually cut deeper each pass.
– Use featherboards and guides to keep the stock tight to the fence and prevent vibration. Clamp down the stock securely.
– Listen to the motor. If it starts to bog down, slow down your feed rate. Don’t force the cut.
– For handheld use, maintain firm control and moderate feed speed. Let the router do the work.
– When using a router table, employ a miter gauge to guide the stock safely and accurately across the blade.
– Use a zero clearance insert to minimize chipout on the backside as the dado exits the cut.
– Always allow the bit to reach full speed before starting the cut. Wait for the RPM to stabilize.
– Blow out dust or vacuum the dado channel between passes. Excess sawdust impacts cut quality.
– Apply paste wax or lubricant to the dado blades periodically. This reduces friction and residue buildup.
Following these guidelines will help you get smooth dados and maximize the life of your router and dado set. The right technique is just as important as choosing the best dado bit.
Frequently Asked Questions
Should I get carbide or HSS dado blades?
Carbide dado sets are preferred for frequent use and professional woodworking because they stay sharp significantly longer and withstand heat better. HSS is a more budget-friendly option for home DIYers doing occasional dados.
What size dado set do I need?
For a router table, 8″ stacked dado blades allow cutting the widest grooves in one pass. But 6″ sets work well for general use and are better for handheld routing applications.
How do I adjust the width of a stacked dado set?
Stacked dado sets include multiple chippers and shims. By adding or removing these in between the outer blades, you can customize the width from 1/4″ to 13/16″ (or wider for 8″ sets).
Should I make multiple passes when cutting a dado?
Yes, it’s better to make several gradual passes rather than try to hog out the full depth in one pass. Go slowly and allow the dado blade time to clear out the waste between progressive passes.
How can I prevent tear out when cutting dados?
Use a zero clearance insert, tight featherboards, and clamp the stock securely to minimize vibration and tear out, especially as the bit exits the cut. A backer board can also help prevent splintering on the backside.
Conclusion
Choosing the right router bit for cutting dado joints is essential for good results. Consider whether a straight or stacked dado set will work best for your needs. Look for carbide cutters for longevity and smooth cuts. And pick a 6″ or 8″ size based on your router’s power and the maximum width grooves you need to cut.
Brands like Freud, Forrest, Dewalt, and Whiteside all offer excellent dado sets to suit different budgets and applications. Following proper safety and handling techniques will also help you safely produce precise fitting dados with minimal chipping. Investing in a quality dado set and using proper router control will give you strong, long-lasting dado joints for all your cabinetry and shelving projects.