When it comes to woodworking joinery, dovetail joints are a popular method for joining two pieces of material at right angles to each other. Dovetail joints interlock the pieces together and allow for an extremely strong and attractive joint. While dovetails can be cut by hand, using a router with dovetail bits makes the job much easier and more precise.
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Types of Dovetail Joints
There are a few main types of dovetail joints:
- Through dovetails – Both sides of the joint are visible.
- Half-blind dovetails – Only one side of the joint is visible.
- Secret mitred dovetails – The joint is completely hidden.
- Sliding dovetails – Used to join pieces at right angles and allow for one piece to slide.
The most common types for furniture and woodworking are through and half-blind dovetails. Through dovetails are simpler to cut but leave the end grain visible from both sides. Half-blind dovetails conceal the end grain on one side for a more elegant look.
Router Bits for Dovetail Joints
To cut dovetail joints with a router, you will need a dovetail router bit set. Here are the main types of router bits used:
Dovetail Bit
This is the primary bit used to cut the tails and pins that interlock to form the joint. The bit has a curved or straight profile that matches the layout of the tails and pins. Dovetail bits are available in several common angles like 14°, 7° and 12°. 14° and 12° are common for hardwood furniture while 7° is often used with softwoods.
Straight Router Bit
A straight bit is used to cut away waste material and square the inside edges of the joint. The straight bit should match the size of the dovetail bit.
Edge Guide Bit
This bit has a bearing that rides along a template or bushing to guide the cut. It allows you to easily trace a pattern for consistent results. Edge guide bits help cut the socket for half-blind dovetails.
Rabbet Router Bit
A rabbet bit can cut a recess along the edge of a board to receive the dovetails. This allows you to create half-blind or full blind dovetails.
| Router Bit | Purpose |
|---|---|
| Dovetail bit | Cut the interlocking tails and pins. |
| Straight bit | Remove waste material. |
| Edge guide bit | Trace patterns for half-blind dovetails. |
| Rabbet bit | Cut recess for half-blind dovetails. |
Choosing a Dovetail Bit Set
When selecting a dovetail bit set, here are some things to look for:
- Angles – Get a 14° and 7° dovetail bit for versatility.
- Bit diameter – 1/2″ is common for most work.
- Carbide tipped – Provides longevity and clean cuts.
- Bearing guided – Allows use of templates and guides.
- Matched sets – Ensures tail and pin angles are aligned.
- Brands – Whiteside, Freud, CMT, and Amana make quality bits.
You’ll also need the corresponding straight, edge guide, and rabbet bits if you want to cut half-blind or sliding dovetails. Buying a set ensures the bits are all sized to work together.
Using a Dovetail Jig
Another option is to use a dovetail jig with your router. Dovetail jigs have precision templates that hold your stock at the correct angles and guide the router to cut smooth, evenly spaced dovetails. This allows you to cut consistent dovetails without complex setup and layout.
Leigh, Porter-Cable, and Rockler make some of the best dovetail jigs. Models like the Leigh D4R include templates for half-blind, through, sliding, and miniature dovetails. Quality dovetail jigs are an investment but can speed up cutting time tremendously in the long run for those who cut dovetails frequently.
Cutting Dovetails by Hand
While using a router is faster and easier, it’s still possible to cut dovetails by hand. This traditional method requires more skill but gives you full control over the joint layout. To hand cut dovetails you’ll need:
- Dovetail saw – Fine rip saw for cutting across grain.
- Chisels – To chop out waste material.
- Marking knife or guage – For laying out tails and pins.
- Sliding bevel gauge – For transferring angled lines.
- Mallet – To drive chisels when paring.
- Straightedge – Check for square pins and tails.
While cutting dovetails by hand takes time and practice, many woodworkers find satisfaction in mastering the skill. Handcut dovetails are often used in finely crafted furniture.
Tips for Cutting Dovetails
Here are some top tips to get clean, tight-fitting dovetail joints with your router:
- Use sharp router bits – Carbide tipped bits stay sharper longer.
- Make light passes – Take shallow cuts to avoid tear-out.
- Clamp stock securely – Prevents workpieces from moving.
- Go slowly – Moving too fast can cause poor cuts.
- Clear chips – Frequently remove debris for optimal cuts.
- Match wood grain – Cut tail and pin boards in matching grain direction.
- Use templates – Avoid layout errors.
- Check fit – Test fit pins and tails before gluing up.
- Sand before assembly – This prevents over-sanding the joint later.
With sharp bits, light passes, and secure stock, you can cut beautiful dovetail joints with a router. Using a dovetail jig simplifies the process further. Additionally, going slowly, clearing chips, and sanding before assembly will give the best results.
Common Problems When Cutting Dovetails
Despite best efforts, there are times when dovetails may not turn out perfectly. Here are solutions to some common router dovetail problems:
Gaps in joints
Gaps usually occur when the router deflects or the wood moves during cutting. Solutions include:
- Secure boards tighter in jig
- Use shallower depth of cut
- Reduce feed rate/move slower
- Replace worn router bit
Tails and pins don’t mate cleanly
The fit can suffer if pins and tails aren’t reciprocal. Check that:
- Same dovetail bit angle was used
- Bit heights and offsets were properly set
- Jig setup is square and accurate
Scorched or burn marks
Burning occurs from dull bits or moving too slowly. Try these fixes:
- Replace router bit if dull, chipped or damaged
- Increase feed rate/move faster through cuts
- Adjust depth of cut to take lighter passes
- Check router speed and reduce if too slow
Solutions are usually adjusting feed rate, depth of cut, clamping pressure, replacing bits or adjusting setup. Checking for problems on scrap first helps troubleshoot any issues.
Conclusion
Cutting dovetail joints for woodworking using a router requires having the right dovetail router bits on hand. At a minimum, you’ll need a dovetail bit, straight bit, and edge guide bit for half-blind dovetails. For best results, opt for carbide-tipped bits sized to match, quality materials, and taking light passes. Using a dovetail jig simplifies the process for accurate, repeatable joints. With attention to router speed, secure clamping, sharp bits, and proper setup, you can achieve beautifully fitted dovetail joints.