Dovetail joints were once a favorite woodworking joinery from the 17th to the 18th century. Most furniture pieces at that time used dovetails to create horizontal case dividers.
Case dividers refer to the rails separating the cabinets’ drawer or door sections. The sliding dovetails play a role in connecting the partitions to the sides of the horizontal case. This method creates a solid assembly of the carcass.
Since sliding dovetails seems challenging, woodworkers of today refrain from using them. There are several methods to create sliding dovetails. Among the options of sliding dovetail methods are the through sliding dovetail and the shouldered sliding dovetail.
What is a Sliding Dovetail?
A sliding dovetail is a type of dovetail joint that connects two pieces of wood at the right angle. The joint is responsible for providing the dovetail’s interlocking strength. Connecting joints occur at the intersection within the area of one of the boards (not at the end).
Carpenters assemble the sliding dovetails by slipping the tail into the socket. Both the socket and tail have equal sizes, as the joint does not require tapering. Joints that fall below six inches in length ensure they are sturdy, as the sliding dovetail creates mechanical strength for the entire woodworking project.
It could be daunting to identify the difference between a regular and a tapered sliding dovetail as they look the same. Their difference is that the socket and tongue of the tapered sliding dovetail use tapering. These parts have a small front and a broader back. Their socket has the same characteristics, to loosen from the end where they interlock. Woodworkers taper the joints that are above six inches for a sturdier structure.
To better understand what sliding dovetail joints look like, they are composed of a socket that looks like a dove’s tail in one board piece. The mating piece of the socket consists of a matching tongue and a socket that looks like a dove’s tail in one board piece.
Sliding Dovetail Joints Applications
Sliding dovetails have several applications, especially if using the traditional dovetail joinery is next to impossible. Their interlocking strength consistently keeps the furniture pieces against heavy pressure. The joints offer an aesthetic value to the furniture due to their concealing characteristics. Involved in this joinery type are two different workpieces slotted together without using mechanical fasteners or glue. The woodworker assembles the separate pieces by slipping the tail into the wood socket. Here are the applications of sliding dovetails:
- Offers shelf support in constructing cabinet drawers. This method allows the back of the drawers to join to the sides and the sides to the front.
- They connect the aprons to the legs of tables and rails to stiles. They do a fantastic job of constructing in-frames and panels.
- Efficient in making drawer guides and runners.
- They are excellent at constructing extension table slides.
- They strengthen the battens to keep the doors, lids, and tabletops from bowing down, working in the same manner when mounting the end of a breadboard.
- They are ideal in mounting case tops and moldings using butterfly or dovetail keys by holding them firmly to the workpieces without restricting the wood’s movement.
- They connect the shelves to the sides of bookcases.
What are the Advantages of Sliding Dovetail Joints?
Sliding dovetail joints has many benefits in woodworking. It creates a beautiful design and several options in wood construction. Here are the advantages of sliding dovetails:
Strong
They are more robust than dado joints. Dovetails can stand without gluing as they resist tension and heavy pressure. Their tailboard is challenging to pull away from the grooved wood pieces. Glues are a plus factor but not a requirement in dovetails as they stay connected to the board. You have to crush and break the wood pieces to separate them!
Clean Looking
Sliding dovetails create a beautiful finish. The slot’s edges are not visible as the dovetailed part hides them. The mortise does not show up when the workpiece is tenoned.
A dovetail showing up is a mark of craftsmanship. Cabinets, tables, bookcases, and chests are some furniture pieces that use sliding dovetails because they look clean on the outside. This joinery allows unique wood construction. They join the case sides directly into the top or construct a chest of drawers with an overhanging front.
Ease of Assembly
Sliding dovetails are easy to assemble using your two hands. The workpieces do not collapse when putting them together as they do not require complex formations of clamps. They are easy to cut using a router.
Resolving Issues with Dovetails Joints
Although dovetail joints are more advantageous than dado joints, there are some issues that woodworking beginners may face. The joints may swell when gluing, especially when working on wide workpieces. You can prevent this by allowing a little loose to the fit.
However, if you let loose the fit, it makes the joint weak and messy. The best remedy is to taper the dovetail’s edge and the slot edge. What makes this joinery advantageous is that it will only tighten if you slide it, even if matching tapers are challenging to achieve. It is still the most straightforward dovetail joint to construct.
Sliding dovetails are easy to assemble when working on solid wood cases with depths of over ten to twelve inches. They work best when joining the sides of the chest of drawers directly into the top. Cupping of the case sides is avoidable if you install a solid-wood shelf at the midspan. Inserting a solid wood bottom works well when you taper a sliding dovetail on wood cases where the sides are close to the floor.
Another issue you will encounter with sliding dovetails is maintaining their stability while working on large pieces of wood on the router bench. There are some techniques to keep them from moving, like using some fingerboards. Clamp them well to the top of the router bench with extended fences. You can also use push blocks consisting of right angles where you clamp the workpieces.
How to Make Sliding Dovetail Joints
Slotting two separate workpieces without mechanical fasteners or glue makes sliding dovetail a unique construction. Their design makes them a popular choice for making ornate designs for furniture pieces, shelves, and drawers. They might look complex, but they are easy to cut manually, provided you are using the right equipment. Here are simple ways to cut a sliding dovetail joint.
Step 1: Preparing the Materials
Sliding dovetail joints require essential tools, such as a router bench, dovetail bit, and a router. Before getting started, decide the size of joints that suit your woodworking project. The starting workpieces should be significant to make any size of sliding dovetail to allow the socket to run smoothly on the entire length of your workpieces.
The socket is the trench where the dovetailed board will slip into it. It is up to you to decide the width of your workpieces. The rule of thumb is that the socket’s depth should be one-third to two-thirds of the total thickness of the wood.
The wood’s quality matter a lot when it comes to the sliding dovetails’ strength when working with any size. Remember that more extensive sliding dovetails look eye-catching, while smaller joints are ideal for creating multiple connections between two board pieces to stay strong without gluing. Shallow cuts as deep as a one-eight inch can remain for several decades for as long as you cut them well.
Step 2: Lay Outing
After deciding the size of your joint, it is time to scribble the placement and size of the cut using a pencil. Scribble two lines of the width down the socket’s face using a ruler to come up with an exact amount.
Cut the socket on the broad side of a timber. Cut the dovetail into the other board’s end to slot the two board pieces perpendicularly.
Step 3: Fitting the Router
Using a spiral down cut or straight cut bit, fit the router to your desired size. The slender end of your dovetail bit should now be inside the collet on the circular base plate of the tool. In a clockwise direction, manually twist the collet’s locking nut until it does not budge anymore. Tighten it using a wrench.
A ¾-inch routing standard stock board and sheets work well in a ¼-inch bit. The job of a router is to hollow out the narrow parts on the board’s surface. Choose a wide dovetail bit to get a clean opening in a single sitting to lessen errors and review them, which consumes a lot of time.
Step 4: Setting Up the Fence
The fence guide should be outside the lines you marked earlier. The router’s bit lies at the midpoint between the width lines, with the guide fence directing your cuts. It is easier to cut using a router table, as it has an adjustable fence.
A DIY edge guide can lessen expenses if you are a beginner. A separate edge guide is required if you use a handheld router. It is available at a home improvement store or rent it from a shop. You need a tape measure, drill, scrap wood, piano hinge, and wood screws to create the DIY edge guide.
Step 5: Routing the Socket
When everything is ready, start gliding the router along the scribbled section of the board and turn it on. Set the router’s base plate flush against the timber and the guide fence. The router bit should be outside of the board’s edge.
Let the router move from the left to the right direction to have a steady, smooth movement while performing the initial pass. Firing the router can irritate your ears and eyes, so use earmuffs and protective eyewear to start cutting.
The bottom part of the vertical edge shaves off, and thanks to the angled dovetail bit following a spiral down cut or straight cut to form a tapered dovetail. Switch the straight bit to a dovetail bit, and continue the steps, moving the router or board along in a linear direction, ensuring it does not veer away from the guide fence.
If you find it challenging to cut a dovetail, you can back off the guide fence a little bit and then make a light scoring cut before getting it right. When performing this step, always see that the dovetail bit should be at the same height as the socket’s depth. Buy a router with a dial to enable you to switch the height setting quickly.
Step 6: Rotate the Socket
Reset the guide fence after turning the workpiece and pushing the router along the board. After carving the sliding dovetail into the groove’s other side, the angled socket is perfect. The socket is complete after making a final pass, which is by rotating the socket at 180 degrees.
Tip: When executing this step, you have to do it carefully and have extra patience. Doing it in a hurry can ruin the whole thing! The sliding dovetail may end up with damage, which looks unsightly and does not serve its purpose- to slot together two board pieces. Open the socket to allow the tenon to fit perfectly.
Step 7: Focusing on the Tenons
After completing the socket, your next task is to fashion the tenon. Begin by attaching an auxiliary fence guide to the main router fence. You can buy a premade auxiliary fence or make a DIY fence using flat scrap wood.
Using hand clamps, clamp the tallest guide fence to the existing guide fence on both ends of the table to extend the height and support the taller pieces. Adjust the auxiliary fence so that only one eight-inch of the dovetail bit is noticeable.
Since most router table fence is only 3 to 4 inches in height, the auxiliary fence should be five inches tall. Let the workpiece stand up vertically on the work surface, holding it in your right hand (if you are right-handed) while the left-hand pins it against the fence of your table.
The back edge should flush with the fence, while the bottom should flush with the router table before cutting the joints. A push block is helpful to keep the board flat against the table fence if your hand feels uncomfortable holding it.
Start cutting the first set of joint cuts after guiding the back edge of the board. The bit planes the board’s vertical surface to an angle complementing the socket’s inside. Gently push the board away from you and press it into the fence. Keep the board stay in place by placing a backer board behind it.
Rotate the board at 180 degrees to create an identical cut on the board’s other side. Turn the router with the other side of the board to create a symmetrical, tight-fitting, and strong joint.
Stop for a while and test if the joint fits the socket after completing the pair of passes. Shave the tenon’s on both sides to achieve the accurate size, adjusting the fence to expose it a little bit. Reset the board and then make the second set of cuts until you finish making the tail with the same depth and width as the socket.
Gently shift the fence to the back at least half of the width’s total amount you want to remove. Repeating the steps on the opposite side of the board will double the amount. You can lightly sand the tenon if it is too large to slide into the socket.
Final Step: Try to Insert the Outer Edge into the Socket Wood
After completing the tenon, slide it into the socket to assemble. Use slight hand pressure to insert the outer edge of the piece into one of the socket’s ends. You can also tap it lightly with a rubber mallet. Although not a requirement, apply glue to one or both pieces to reinforce the sliding dovetail joint.
FAQs
Are Sliding Dovetails Strong?
Sliding dovetails are clean-looking and have stronger joints for constructing chests of drawers, cabinets, tables, and other furniture items. They are easy to cut and assemble using a primary router. Joint swelling after gluing is preventable if you taper the joints.
What is the Ideal Dovetail Bit?
The rule of thumb when choosing the dovetail bit is that more significant bits produce stronger joints ensuring that the tip should not be wider than the part’s thickness where the end of the dovetail tenon takes place. A half-inch shank is preferable to minimize breakage while working on the groove. The router table’s surface should be clean and flat.