Dovetails, what’s the big deal?

Dovetails joints have been around since the times of ancient Egypt. Earlier civilizations recognized it as an extremely powerful joint in both furniture and stone construction.

The dovetail joint’s strength is partly due to the tapered shape of the tenon and mortise, which, when assembled, makes it virtually impossible to take apart, especially when glued.  The second reason for its strength is that it has a larger gluing area than butt-jointed components. After the joints are pressed together using a very small amount of glue, you will need a strong hammer to break the joints apart. Drawers are used every day and often contain heavy items. Breaking apart causes undue stress for the client and ultimately you when it needs replacing.

In addition to the design’s durability, one should not overlook the dovetail’s aesthetic look, signifying quality.  For many cabinet manufacturers, the decision to add dovetail drawer boxes to their cabinets provides a perception of quality. Once you open the drawer and see the dovetail design, it elevates your product in the consumer’s eye. But why dovetail machine is right for my operation? When deciding to produce your own drawer boxes, a number of factors come into play when selecting the equipment required.

Akhurst Machinery - Blog Post - Dovetails

What types of dovetail joints can you find?

Half Blind Dovetail

For cabinetry purposes, the most popular joint is the blind dovetail. The reason it is desirable for cabinetry is in most cases, you will be attaching a drawer front to the end, and the blind dovetail tenons are not exposed on the other end. A blind dovetail is a typical joint for most manual and automatic dovetailers. Most manual and semi-automatic have a fixed pitch or intent spacing, while CNC dovetailers allow for greater flexibility on the type of blind dovetail created with various pitch and dovetail widths. All of our dovetail machines can produce this type of joint.

Through Dovetail

A through dovetail is typically used in furniture production where the builder wants to showcase their joinery method for its aesthetic purposes. There are many styles of through dovetails, some of which require complex cutting.  For machine purposes, the through dovetail can be machined on all our machines but with different joints. Some produce a through dovetail where the exposed ends are rounded. The CNC dovetailers have the flexibility to produce a proper box joint by machining parts fed vertically into the machine. With this method, you produce the male and female and female joints separately.

French (Slide) Dovetail

The French dovetail can be used in a number of construction methods, including joining shelves to gables. For drawer boxes, a French dovetail is used by attaching the sided of the drawer directly to the drawer front.  You find this in high-end furniture production. This can only be processed on a CNC dovetailer or a dovetailer specific to French dovetails. This type of joinery is not very common in North America.

Fixed Pitch vs. Variable

A fixed-pitch dovetailer means that the indent spacing is fixed. For instance, the Cantek JDT75 has a fixed pitch of 25mm. It can produce joints only on 25mm centers; thus, it is recommended for reducing setup times that the drawers be varied in heights of 25mm. This way, you guarantee the same size dovetail on top and bottom of the drawer and not have a “half-tail” as shown below. If you do not do this, you could be left with a poorly machined dovetail on one side of the drawer, and it could break during assembly. Some shops will purchase their material already grooved to accept the 1/8″ bottom. Dovetailing aims to hide this groove within the dovetail so it does not show on the exposed end.  Achieving this with a fixed pitch dovetailer can be quite difficult unless there is a lot of pre-planning to the groove’s location.  When pre-purchasing material, this can prove to be difficult. The groove can be more easily concealed when you have a variable pitch as you can choose the starting location of the dovetail, and it can be optimized for the height of the drawer, so you are not limited to fixed drawer heights.

A variable pitch dovetailer allows you added versatility in the types of dovetails that can be produced. You can produce wider dovetails on a CNC dovetailer if desired, and you can choose the joint’s width.

What about your production requirements?

When considering a dovetail machine, a primary consideration is going to involve your production needs. Modern dovetail machines are designed to accept all four sides of drawer components (for blind and some through dovetails). You machine the male and female joint simultaneously, ensuring a nice tight fit and speeds up production. The loading area’s width on the machine will determine how deep a drawer you can machine with all four parts. This method allows for a box to be completed in two passes as parts are simply rotated to machine both ends. For deeper drawers, you are limited to machining two parts at a time, which requires four passes for a complete box.

Cantek JDT65
Cantek JDT75
Omec 650A
Omec 750CN
Omec F11TS
Production Capacity / Hour
15 to 20 boxes
30 to 40 boxes
Up to 40 boxes
Up to 60 boxes
Up to 120 boxes
Operation
Manual
Automatic
CNC
CNC
CNC
Width Capacity
420mm
430mm
400mm
530mm
770mm
Pitch
1”, 1.5”, 2”, 2.5”
25mm
25mm & 50mm
Variable
Variable
Type of Joints
Blind, Through, Box
Blind, Through
Blind, Through, Box
Blind, Through, French, Box
Blind, Through, French, Box

Learn more about most types of material.

You can produce dovetails out of a wide range of wood materials, but not all dovetailers can produce a quality finish and all types of material. For cabinetry, birch plywood and solid wood are the most common materials used in drawer production. However, they machine very differently. It used to be that dovetailers used interlocking gears to turn multiple spindles at the same time. This meant high production, but the finish could be sub-standard at times. The RPM of these spindles were around 6000 RPM which is far too slow for machining plywood. The slow RPM cutters would result in “furring” or a poor-quality cut requiring sanding when machining with plywood. Today, most dovetailers produced have an RPM of 18000, making them ideal for machining a wide range of materials.

Some shops purchase their drawer material pre-finished if they do not have a proper finishing department. The pre-finished plywood surface can be quite brittle, and machining it can result in chipping along the face. A CNC dovetailer works very well with this material as it can score the material before plunging into it. This acts almost like a scoring blade on a panel saw.

How to assemble?

When assembling dovetail drawer boxes, you have a few choices. Prior to assembly, glue should be dropped in the pocket of each tail. Option 1 is to use a trusted mallet to tape the parts together. The dovetails should fit together approximately 2/3 the way and require force to close the joint. Option 2 is a proper drawer clamp. A drawer clamp allows you to easily assemble the drawer in the clamp itself and then press the pieces together pneumatically or mechanically. The simple advantage of this system is the speed and squareness of the drawer. Our DOUCET DWM is available in two models to accommodate up to 36″ or 42″ width drawers. The rapid change clamp allows for fast changeover between various drawer widths.

How to machine for soft-close drawer slides?

The popularity of under-mount soft-close hardware has taken off in the past number of years. It has the advantage of being out of sight, so aesthetically pleasing. It maximizes the drawer’s width as you do not need space on either side for hardware. To mount the under-mount slides to the bottom of the drawer, you need to notch out the drawer’s back according to the width of the slide you are installing, and this can range by manufacturer. There is a small location hole for the slide to fix into that also needs to be machined. Our CANTEK JEN60 can automatically process the notch with a wide insert knife dado cutter and will drill the location hold simultaneously. The alternative to this would be machining the drawer parts on a table saw with dado cutter and using a drill template for the location hold. Both work, your production requirements will help you justify one solution over the other, processing up to 220 drawer boxes per hour.

Stay tuned and learn more about every woodworking solution we provide to the market.

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