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CNC joint examples and CAD files

Here you will find examples of CNC compatible joints with 2d dxf and 3d iges files you can use to implement into your designs or use for inspiration to create your own variation of joint.

The joints here are listed into joint catagory, type and variation. Navigate the joints using the menu below.




Frame Joints | Frame Corner Joints |
Halved Dovetail Corner

Halved Dovetail Corner - www.southwestcnc.co.uk

Scarf joints are next to tenon joints among the most frequently used joints in wood and furniture construction. While traditional scarf joints are considered to be not very durable, the technical qualities of CNC-compatible joinnts have been decidedly improved.
The halved dovetail corner is a corner joint that resists tensile forces. The geometry of the asymmetrical dovetail is decisive for the tensile strength. However, it is exactly this asymmetry of the dovetail that frequently seems to render the use of this joint problematic from a design viewpoint.

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Frame Joints | Frame Corner Joints |
Dovetail Key Corner

Dovetail Key Corner - www.southwestcnc.co.uk

For the Dovetail Key Corner, the framing timbers are joint with a shaped part, the dovetail key. The dovetails of the dovetail key take on the tensile stress and the mortised tenon on the underside of the key guarantees the exactness of the angle. The joint does not have to be right-angled, this type of corner joint can be used for any angle. The thickness of the key should be at most half the thickness of the framing timbers. Suitable materials for the corner key are multiplex plywood, acrylic glass or aluminium. Depending on the choice of material, the corner key will show more or less.

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Frame Joints | Frame Corner Joints |
Mitre Joint with Dovetail Key

Mitre Joint with Dovetail Key - www.southwestcnc.co.uk

Today, frame corners are mostly joined with tongues, tenons or dowels that are suitable for machine processing. The dovetail keys have been completely forgotten, even though they have been used extensively in Europe as well in Japan as the "Chi-giri-iri-o-dome-tsugi". Like the traditional models, the Mitre Joint with Dovetail Key is held together by the dovetail key. The framing timbers are tightly wedged together. The dovetail key can be specially emphasised by the use of different woods or materials.

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Frame Joints | Frame Corner Joints |
Jigsaw Mitre Joint

Jigsaw Mitre Joint - www.southwestcnc.co.uk

Corner joints with mitred framing timbers are considered to be particularly harmonious from a design viewpoint. From a technical viewpoint, however, the traditional mitred frame joints count among the ÒweakÒ wood joints.
Like the dovetail corner scarf, the Jigsaw Mitre Joint distinguishes itself through its good technical qualities. The geometry of the two opposing shaped tenons, whose lines run parallel either to the frame or to the mitre, guarantees tensile strength and at the same time the harmony of the joint.

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Frame Joints | Frame Corner Joints |
Halving with Elliptical Tenon

Halving with Elliptical Tenon - www.southwestcnc.co.uk

A shaped tenon, here in the shape of an ellipse, can be added to a common halving to improve its tensile strength. To avoid shearing of the tenon, its geometry needs to be chosen so that it uses the maximum fibre length possible. An open or a blind version can be chosen for the tenon. Like with all frame joints, the correct choice of the framing timber is of vital importance for the quality of the joint. To avoid an opening of the joint, the main direction of shrinkage of the wood must not correspond with the width of the framing timber.

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Frame Joints | Frame Corner Joints |
Double Jigsaw-Hook Corner

Double Jigsaw-Hook Corner - www.southwestcnc.co.uk

The Double Jigsaw-Hook Corner is a decorative corner joint with tensile strength. The hook that is fitted to the cross bar needs to be equipped with sufficient projecting wood to enable it to withstand the tensile stress. The hook at the cross bar also secures the joint against shifting sideways. The jigsaw tenon can take on a multitude of shapes, geometric, organic, or floral depending on to where it is applied.

Like for all frame joints, it is important that the width of the framing timbers does not surpass 10 cm.
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Frame Joints | Cross Joints |
Oval Shouldered Halving

Oval Shouldered Halving - www.southwestcnc.co.uk

Common halvings are used wherever two timbers are supposed to cross in one plane. They are let into each other so that the top and undersides are on one level.
The Oval Shouldered Halving is not only a decorative joint, but also one that is very stable and with an exact fit when compared with the common halving. The increased fitting surface prevents a torsion of the two timbers. The oval shouldered surfaces, that can not be produced with traditional tools, are also a sign for a CNC-compatible joint.

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Frame Joints | Cross Joints |
Dovetailed Cross Halving

Dovetailed Cross Halving - www.southwestcnc.co.uk

Cross halvings are traditionally produced in a multitude of variants. For example the mitred cross halving, the tabled cross halving, or the cross halving with shouldered dovetails, the Japanese "Shiho- ari-kumi-te".
It was the model for the Dovetailed Cross Halving. The shouldered dovetails give the joint a decorative effect, as well as adding to its stability. As opposed to the traditional execution of the joint, which is very costly, the dovetailed cross halving can be produced on the CNC-router without any problems.

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Frame Joints | Cross Joints |
Jigsaw Cross Halving

Jigsaw Cross Halving - www.southwestcnc.co.uk

The Jigsaw Cross Halving has been developed from the Dovetailed Cross Halving. It exemplarily shows that, while keeping the construction principle, a multitude of variants can be developed which have each in its own right an individual design expression.
The jigsaw tenon of the cross halving points without any doubt to a manufacturing of the joint with a CNC-router, as it can not be made with traditional tools. Depending on the shape, size and arrangement of the jigsaw tenon, a joint with good or not so good technical qualities is created.

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Frame Joints | Cross Joints |
Cross Mitre Joint with Jigsaw Key

Cross Mitre Joint with Jigsaw Key - www.southwestcnc.co.uk

While connectors like tongues and dowels are normally hidden in the joint, the jigsaw key of the here presented joint becomes a decorative element. It joins the individual framing timbers and gives the joint a good resistance to tensile forces. As there is a lot of strain on the key, it should be made out of an appropriate material, like, for example, multiplex plywood.
Jigsaw keys can not only be used for cross halvings, but also for lengthenings, T-shaped joints, and wherever a certain numbre of framing woods need to be joined in one point.

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Frame Joints | Lengthenings |
Shouldered Dovetail

Shouldered Dovetail - www.southwestcnc.co.uk

Traditionally, lengthenings with dovetail tenons were used wherever frame woods need to be secured against longitudinal extension. In contrast to the through dovetail tenon, which is a joint solely designed to resist tension, the Shouldered Dovetail Joint also keeps the frame wood onto which the dovetail tenons are worked on from slipping through. The shoulder is generated by a parallel shift of the contour of the tenon. The maximum distance between the two contours is defined by the ratio of the tenon to the width of the frame.

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Frame Joints | Lengthenings |
Shouldered Triple Dovetail

Shouldered Triple Dovetail - www.southwestcnc.co.uk

While the Shouldered Dovetail is particularly suited for the lengthening of narrow framing timbers, the here presented Shouldered Triple Dovetail with the lateral dovetail tenons has been primarily developed for broarder frames. The two lateral tenons and the opposing tenon prevent the framing timbers from twisting and improve at the same time the absorption of the lateral forces. The interplay between single and double tenons and top and undersides also adds interest to the joint from a design viewpoint.

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Frame Joints | Lengthenings |
Double Dovetail

Double Dovetail - www.southwestcnc.co.uk

The Double Dovetail Joint combines the advantages of the dovetail tenon with those of scarf joints. They resist longitudinal tensile forces, resist shearing stress due to the size of the fitting lateral surfaces, and are secured against perpendicular shift by the scarf. There are various versions of the Double Dovetail Joint possible.
Unlike the Symmetrical Double Dovetail, the Double Dovetail with both dovetails pointing in the same direction is very little used in traditional furniture and wood construction. The reasons for this lie in the costly manual making and are thus no longer valid for the production on a CNC-router.

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Frame Joints | Lengthenings |
Triple Dovetail

Triple Dovetail - www.southwestcnc.co.uk

The Triple Dovetail is a variant of the Double Dovetail Joint and is particularly suited for the lengthening of wide framing timbers. On the top side of the closed joint only one big dovetail tenon is visible, on the underside there are two smaller ones. They prevent the framing timbers from twisting and strengthen the joint as they shorten the length of the flattened surface. Dovetail scarfs fit in with the group of the scarf joints as well as with the group of the table joints, which can occasionally lead to misunderstandings.

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Frame Joints | Lengthenings |
Symmetrical Double Dovetail

Symmetrical Double Dovetail - www.southwestcnc.co.uk

Model for the Symmetrical Double Dovetail is the Japanese "Ryo-men-ari-tsugi". Its widespread use in Japanese wood construction is due to its simple and efficient making. For symmetrical joints, both parts are scribed and worked upon together. In the age of the CNC-router this advantage, which meant that a lot of time could be saved when joints were traditionally scribed, is not decisive any more. Joints that were formerly a lot more costly to make can now be manufactured just as efficiently as symmetrical joints.

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Frame Joints | Lengthenings |
Double Jigsaw

Jigsaw Cross Halving - www.southwestcnc.co.uk

The Double Jigsaw is a further development of the Symmetrical Double Dovetail Joint, taking into account the possibilities that come along with CNCproduction. For example, the ability of the CNCrouter to cut so-called free shape contours. The contours can be designed on a graphics tablet and revised in a CAD-system. The condition being, that the contour can be processed with the chosen tool.
The Double Jigsaw is a very decorative joint, which being employed as a constructive detail becomes a design characteristic of the furniture piece.

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Frame Joints | Lengthenings |
Plain Scarf with Dovetail Keys

Plain Scarf with Dovetail Keys - www.southwestcnc.co.uk

Loose connectors, like dovetail keys, are used wherever joints need to be opened occasionally, or where it is not possible to loose length due to just dimensions. The loose connectors can take a multitude of shapes and be made out of different materials. Depending on the choice of material for framing timbers and connectors, the joint will show more or less. If the connectors are made out of wood, they should be made out of well dired hardwood. As the loose connentor is only inlaid, the scarf needs to be supported in order to prevent it from slipping through.

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Frame Joints | Lengthenings |
Gooseneck Mortise and Tenon Joint with Stub Tenons

Gooseneck Mortise and Tenon Joint
with Stub Tenons - www.southwestcnc.co.uk

The gooseneck or hammer-head tenon is widely used in Japan for the executionof lengthenings with tensile resistance. The joint is characterised by the long tenon with a head at the end that is shaped like a reversed dovetail.
The Japanese ÒMechigai-koshikake-kama-tsugiÒ is the model for the Gooseneck Mortise and Tenon Joint with Stub Tenons. From a production point of view, it is a very costly and difficult joint. While the simple hammer-head tenon is very susceptible to torsion, the here presented gooseneck is very stable in this respect due to the two rabbets and the stub tenon.

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Frame Joints | Lengthenings |
Ginkgo Scarf with Stub Tenons

Ginkgo Scarf with Stub Tenons - www.southwestcnc.co.uk

The Ginkgo Scarf with Stub Tenons is a consistent further development of the Gooseneck Mortis and Tenon Joint with Stub Tenons, taking into account the possibilities opened up through CNC-production. Without changing the technical qualities, a new and very decorative lengthening joint was created. The tenon in the shape of a Gingko leaf can not be produced with traditional tools.
The here presented joint exemplarily shows, that through the use of CNC-routers, it is possible to give wood joints a new, individual and so far unimagined shape while keeping their function.

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Frame Joints | Stop laps |
Shouldered Dovetail Halving

Shouldered Dovetail Halving - www.southwestcnc.co.uk

Halved joints are used wherever cross bars are joined to framing timbers forming a T-shape, and where a whole scarf would weaken them too much. The length of the scarf should not surpass half the width of the framing timber.
The Japanese ÒAri-kakeÒ is the model for the Shouldered Dovetail Halving. It is a joint that resists strain in all directions. This is above all achieved by the shoulder which prevents the cross bar from twisting and relieves the load from the dovetail.

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Frame Joints | Stop laps |
Stop Lap with Jigsaw Key

Stop Lap with Jigsaw Key - www.southwestcnc.co.uk

Keys are generally used where special demands are placed upon the connector, demands which the framing woods themselves cannot fulfil, or where there is not enough wood to execute a joint. For the Stop Lap with Jigsaw Key, the two framing woods are joined with a jigsaw-shaped key. The key can be made out of multiplex plywood, acrylic glass or various hardwoods. An appropriate choice of material and colour enhances the decorative quality of the joint. To prevent the cross bar from slipping through, the joint can also be made with a shoulder.

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Frame Joints | Stop laps |
Hooked Jigsaw Halving

Hooked Jigsaw Halving - www.southwestcnc.co.uk

Table cross joints make it possible to secure connected scarf joints against tension. A precondition is, however, a sufficient length of the surpassing wood of the table.
The Hooked Jigsaw Halving is a very decorative stop lap. The circular table secures the joint not only against tension, but also against torsion and shearing of the cross bar. The jigsaw table that juts out beyond the outer contour of the framing timber is responsible for the aesthetic quality of the joint, but, at the same time, it restricts its use.

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Board Joints | T-shaped joints |
Finger Tenons

Finger Tenons - www.southwestcnc.co.uk

In furniture construction, the Finger Tenons are suitable for the fitting of shelves, cross bars and footrails. These items are mortised into the side parts being either executed as an open or as a blind version.
The Finger Tenons, like the jutted out finger tenon corner joint, differ from their traditional models in the more deeply cut rebate on the inner corner of the tenon base. The width of the Finger Tenons should be at least three times the diameter of the router bit. The H-shaped mortises are, as well as the shape of the tenons, a typical characteristic of CNC-compatible manufacturing.

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Board Joints | T-shaped joints |
Fingertip Tenons with Lateral Positioning Tenons

Fingertip Tenons with Lateral Positioning Tenons - www.southwestcnc.co.uk

The Fingertip Tenons for T-shaped joints were developed parallel to the Fingertip Tenon Corner Joint. It is characterised by its slender tenons and can be executed either open or blind. Ideally the width of the tenons equals the width of the router bit. It is recommended, however, to chose a one to two tenths of a millimetre larger width of the tenons, so that the router can work the tenons without problem in one go.
The outer tenons have been designed as positioning tenons in order to avoid a lateral shift of the tenons. Furthermore they prevent a distortion of the mortised parts.

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Board Joints | T-shaped joints |
Fingertip Tenons with Central Positioning Tenon

Fingertip Tenons with Central Positioning Tenon - www.southwestcnc.co.uk

TThe Fingertip Tenons can not only be executed with lateral positioning tenons, but also with one central positioning tenon. The latter version is mainly used when there is no great need to secure the mortised parts, e.g. cross bars and foot-rails, against torsion. If the mortised parts are broad, it is recommended to place more positioning tenons in the row of tenons.
The Fingertip Tenons can be executed in solid wood as well as board materials. When solid wood is used, one needs to pay attention to the main direction of shrinkage in the mortised parts.

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Board Joints | T-shaped joints |
Clip Tenons

Clip Tenons - www.southwestcnc.co.uk

The use of modern derived wood products and the transfer of jointing techniques from other fields necessarily leeds to new and innovative solutions. Clip Tenons make a detachable joint which consistently uses the springiness of multiplex plywood. The model for this joint is found in the field of synthetic materials.
The Clip Tenons are made in such a way that both clip hooks flip back to their original position after being pushed through the mortises in the side part und thus secure the joint. The joint can be detached manually again and again by pressing together both clip hooks.

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Board Joints | T-shaped joints |
Catch Tenon

Catch Tenon - www.southwestcnc.co.uk

The Catch Tenon Joint is a detachable corner joint. However, unlike traditional solutions in the form of connectors made out of metal or synthetic materials, the joining elements are part of the individual pieces of furniture. The Catch Tenon Joint can therefore be put together and detached without tools, which makes it particularly suitable for packaged furniture.
When assembling, the catch is pushed through the matching latch and as soon as it is in the right position it flips back. The joint is secured against tension by the catch, while the tenons take on the arising forces.

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Board Joints | Lengthenings |
Lapped Dovetail

Lapped Dovetail - www.southwestcnc.co.uk

The Simple Lapped Dovetail can be used to lengthen framing timbers, as well as boards or panels. Due to the dovetailed tenons, the joint is secured against longitudinal tension, while the scarf prevents a perpendicular shift.
For decorative purposes, the tenons can take different shapes, e.g. like Ginkgo leaves, which can be arranged regularly or freely.

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Board Joints | Lengthenings |
Double Lapped Dovetail

Double Lapped Dovetail - www.southwestcnc.co.uk

As opposed to the simple version, the manufacturing of the Double Lapped Dovetail is much more costly. In exchange one gets a joint that is more durable and very decorative from both sides. The second row of dovetails is offset and this prevents an opening of the lower rabbet caused by loading, which can occur with the simple version. Depending on the precision requested of the router, the joint can be executed as detachable or glued versions.

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Board Joints | Lengthenings |
Board Lengthening with Asymmetrical Dovetail Keys

Board Lengthening with
Asymmetrical Dovetail Keys - www.southwestcnc.co.uk

The Board Lengthening with Asymmetrical Dovetail Keys is a very decorative joint. Even though joints with dovetail keys are very old, they are hardly used in furniture construction. The dovetailed keys, which here are presented in an asymmetrical and alternating version, secure the joint against tension. The dovetail keys can be used for lengthenings as well as for width joints, or for securing cracks in solid wood boards and planks. The decorative value of the joint can be increased by the use of fine woods or other materials.

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Board Joints | Lengthenings |
Board Lengthening with Jigsaw Keys

Board Lengthening with Jigsaw Keys - www.southwestcnc.co.uk

The Board Lengthening with Jigsaw Keys clearly shows that let in loose connectors, a Jigsaw Key in our example, can take on a multitude of shapes. They can also be arranged in various ways in order to make a durable as well as decorative joint. When the Jigsaw Keys are used in width joints, due to the opposing main directions of shrinkage, it is recommended to keep the length of the keys to a minimum and to slightly undercut them at the ends.
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Board Joints | Lengthenings |
Lengthening with Meander Key

Lengthening with Meander Key - www.southwestcnc.co.uk

Unlike other loose connectors, e.g. the dovetail key, there is no traditional model for the Meander Key. The reason for this is that a key of this shape can only be made out of material that can stand longitudinal as well as cross tension. Suitable materials are, inter alia, multiplex plywood, acrylic glass or aluminium. When joining boards with a Meander Key, it is important to make sure that the wood is well dried and that there is enough material left at the inner radii of the key to withstand the tensile force.

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Board Joints | Lengthenings |
Detachable Lengthening with Key

Detachable Lengthening with Key - www.southwestcnc.co.uk

The Lengthening with Key was designed from the start to be a detachable joint. It can be detached and relocked at any time without tools. The region around the joint is flattened on both boards and is provided with a slot. When both parts are assembled, the key is introduced into the interconnected slot and then turned. The geometry of the slot stops the key after a quarter turn. As the strain on all parts of this joint is particularly high, it is recommended to execute it in multiplex plywood.

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Board Joints | Corner Joints |
Finger Tenons

Finger Tenons - www.southwestcnc.co.uk

Due to the superior stability of finger tenons, it is hard to imagine traditional furniture construction without them.
Finger Tenons are the simplest of the CNC-compatible tenons. They differ from their traditional models - the European finger tenon or the Japanese ÒGo-mai-hozo-gataÒ - through the deeper drawn cuts at the inner corners of the tenon base. The thus created jutted out tenons are characteristic for CNC-compatible manufacturing and give the joint its individual character. The width of the tenons should be at least three times the diameter of the router bit.

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< Board Joints | Corner Joints |
Lapped Finger Tenons

Lapped Finger Tenons - www.southwestcnc.co.uk

The Finger Tenon Joint can also be executed as a lapped variant. The Lapped Finger Tenons are used wherever one of the two surfaces must not be interrupted by the joint for aesthetical or functional reasons, for example, drawer fronts or cupboard sides.
Like all other tenons, the lapped finger tenons can be made using solid wood or various board materials like multiplex plywood or MDF.

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Board Joints | Corner Joints |
Secret Finger Tenons

Secret Finger Tenons - www.southwestcnc.co.uk

The Secret Finger Tenon Joint hides the tenons in its interior from curious glances. As opposed to the traditional secret tenon mitre joint, the CNC-compatible version leads to a rabbet at the front edge. Secret joints are traditionally looked upon as the height of a cabinet-makerÕs craftsmanship. Sweat and skill of the craftsman are hidden from the eyes of the world in the interior of the joint. It is said: Out of awe for his material, the cabinet-maker humbly conceals his own efforts in making a piece of furniture.

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Board Joints | Corner Joints |
Fingertip Tenons

Fingertip Tenons - www.southwestcnc.co.uk

The Fingertip Tenons are slenderer than the Finger Tenons. Ideally the width of the tenons equals the diameter of the router bit. In order to avoid that the tenons slip through, a special positioning tenon is placed at either end of each row of tenons. In the case of broader rows of tenons, additional positioning tenons can be inserted.
Due to the greater number of tenons for an equal width, the Fingertip Tenons, as opposed to the Finger Tenons, have a higher friction tight which leads to a higher durability of the joint.

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Board Joints | Corner Joints |
Lapped Fingertip Tenons

Lapped Fingertip Tenons - www.southwestcnc.co.uk

The lapped version of the Fingertip Tenons is used wherever one of the two surfaces must not be interrupted by the joint for aesthetical or functional reasons.
Depending on the degree of precision according to which the joint has been machined, we get a perfect fit joint that is durable simply by friction tight and can be detached at any time, or a joint that easily comes undone and needs to be glued. The exactness of the fit depends also on the correct tool, as well as feed and the depth of the Z-step.

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Board Joints | Corner Joints |
Secret Fingertip Tenons

Secret Fingertip Tenons - www.southwestcnc.co.uk

The secret version of the Fingertip Tenons Joint leads to a rabbet at the front edge of the assembled joint. From a design-oriented viewpoint, this rabbet is an interesting design detail on furniture. For traditional wood and furniture construction the rule was not to let a joint show, however complicated its execution might have been. But today, in the age of industrial furniture construction with its invisible connectors in the form of dowels and lamellos, times have changed. The demonstratively shown joints are a sign for the quality of furniture made by a craftsman.

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Board Joints | Corner Joints |
Fingertip Tenons with Key

Fingertip Tenons with Key - www.southwestcnc.co.uk

A special form of the Fingertip Tenon is the variant with key. Its characteristic are the prolongated tenons that have a groove on the outside which perpendicular runs across the tenons. After assembling the joint, a key with a square end-grain cutting is inserted into the groove and thus secures it against tension.
There is no direct model for the Fingertip Tenons with Key. Ideas came from decorative forms of various corner locks, where surpassing tenons are employed as decorative elements.

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Board Joints | Corner Joints |
Hammer Tenons

Hammer Tenons - www.southwestcnc.co.uk

Similar to the dovetail tenon joint, a characteristic of the Hammer Tenons is the fact that it withstands tension in one direction even without glue. This is not achieved through trapeze-shaped dovetails, but through tenons that are shouldered in their width, so-called Hammer Tenons. The best tensile strength of the joint is given when the thickness of the inner Hammer Tenon equals half the thickness of the board. A stop in the centre of the tenon base prevents the tenons from slipping through. The Hammer Tenons can be made using solid wood as well as various board materials or three-layer boards.

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Board Joints | Corner Joints |
Lapped Hammer Tenons

Lapped Hammer Tenons - www.southwestcnc.co.uk

Like most tenon joints, the Hammer Tenons can also be made as a lapped version. As the Lapped Hammer Tenons are durable against tension in one direction even without glue, as opposed to the Finger or Fingertip Tenons, there are particularly suitable for drawers when the front should not be interrupted for design reasons. The strength of the rabbet that covers the hammer tenons should be between 1/4 and 1/3 of the thickness of the material. If the sides are joined with the use of hammer tenons, they prevent a warping of the surface.

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Board Joints | Slotting Joints |
Simple Slotting Joint

Simple Slotting Joint - www.southwestcnc.co.uk

The here presented slotting joints were created when it became necessary to develop detachable joints for demountable furniture manufactured from modern wood-derived materials, like multiplex plywood for example.
For the Simple Slotting Joint, a slot is cut up to the middle of the board, at the end of the two construction elements that are to be joined. In order to achieve a high durability of the joint despite frequent variations of the thickness of the board, the slot is executed 2 mm less than the thickness of the board and a 2 mm groove is cut as a prolongation of the slot. An exact slotting together of the joint is thus made possible.

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Board Joints | Slotting Joints |
Slotting Girder Joint

Slotting Girder Joint - www.southwestcnc.co.uk

For the Slotting Girder Joint, the horizontal construction element, e.g. a shelf, is placed onto the tenon of the girder and pushed back in the slot that has been provided. Thus the board can not tip over and a durable joint is created that can be detached again at any time. Should the shelf be flush with the back of the girder, the self will be provided with an additional slot at its back edge. The Slotting Girder Joint is used for example for shelves. An advantage of the joint is a quick assembly and dismantling of the shelf without tools and small connectors.

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Board Joints | Slotting Joints |
Double Lapped Slotting Joint

Double Lapped Slotting Joint - www.southwestcnc.co.uk

As opposed to the Simple Slotting Joint, the Double Lapped Slotting Joint is particularly suited for wider construction elements. A slot is cut in the wide construction element from above and from below and the narrow parts are inserted into it. Depending on the lay-out of the two slots, aligned or offset, the narrow parts either butt-joint in the middle or overlap each other. When they overlap each other, like in the case presented here, the thus created shoulder can be used as a rest base for further parts.

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Board Joints | Slotting Joints |
Hooked Slotting Joint

Hooked Slotting Joint - www.southwestcnc.co.uk

For the Hooked Slotting Joint, the cross bar is pushed through a slot in the girding side or headboard and thus hooked. It is secured through its own weight, and can be detached at any time. The groove cut in prolongation of the slot not only permits to even out variations in the thickness of the material, but also guides the cross bar along its width and thus secures it against torsion.
The Hooked Slotting Joint is suitable for bed construction or for cross bars of tables.

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Board Joints | Slotting Joints |
Double Lapped Slotting Joint with Key

Double Lapped Slotting Joint with Key - www.southwestcnc.co.uk

The Double Lapped Slotting Joint with Key is useful wherever the joint needs to be secured against unintentional loosening. The two lapped construction elements are locked with a turnable key and the enclosed part is thus fixed. Around the key, the construction elements that are to be secured are flattened in a circular area and a slot is cut in it. The key, that should be made of multiplex plywood as it has to withstand great strain, is inserted in the slot created when assembling both parts and then turned. The geometry of the slot is such that the key stops after a quarter of a turn.

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Carcass Joints |
Tenon Joint with Star-Shaped Mortise

Tenon Joint with Star-Shaped Mortise - www.southwestcnc.co.uk

Tenon joints count among the oldest wood joints. It is impossible to imagine furniture and carcass construction without them. They have been replaced more and more by dowel joints due to industrial furniture production. They are, nevertheless, still superior in terms of durability. For the Tenon Joint with Star-Shaped Mortise, the tenon of the cross bar, that has beeen shouldered up to half the thickness of the wood, is placed into the vertical framing in such a way, that it is flush at the front. The Star-Shaped Mortise is a result of machining the joint on a CNC-router. The extended corners of the mortise ensure an accurate support of the rectangular tenon.

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Carcass Joints |
Shouldered Tenon

Shouldered Tenon - www.southwestcnc.co.uk

The Shouldered Tenon combines the idea of the housed butt joint with the idea of the tenon joint. The flattened part of the vertical frame prevents the horizontal shift of the cross bar, while its side forces are transmitted by the tenon.
The Shouldered Tenon Joint can be executed as a blind or open version. For the blind version, the tenon should be shorter than the depth of the mortise in order to avoid the tenon forcing on the mortise ground in case the wood shrinks. The Tenon Joint can also be secured against tension with the help of wood pins.
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Carcass Joints |
Locked Leg Framing

Locked Leg Framing - www.southwestcnc.co.uk

The Locked Leg Framing is a removable carcass joint, which is used wherever legs are joint with framing rails, as for example for tables and beds. The front and back rails have tenons, the side rails have mortises. Both rails are flattened on the outside around the tenons as well as around the mortises. When assembling the joint, the rails will be slotted together and the leg will be introduced from below in the flattened area. The rails thus resist tensile forces and, at the same time, ensure a high stability of the angle joint.

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Carcass Joints |
3-Dimensional Finger Tenon Joint

3-Dimensional Finger Tenon Joint - www.southwestcnc.co.uk

The 3-Dimensional Finger Tenon is a joint used for three-dimensional space structures in furniture construction as well as trade fair construction. The joint, illustrated here as a corner solution, consists of two basic elements: the outer and the inner framing timber which run parallel to each other. These two almost identical elements enable the problem-free assembly of complex structures. Because of their geometry and the stress under which element is put, the 3-Dimensional Finger Tenon Joint should be made, if at all possible, of multiplex plywood.

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A guide written by Bernhard E. BŸrdek a professor for design-methodology, product planning and interface-design at the Hochschule fŸr Gestaltung Offenbach, Jochen Gros a professor for design theory at the Hochschule fŸr Gestaltung Offenbach, Martin Krautera Hochschule fŸr Gestaltung Offenbach graduate and Friedrich Sulze, a master cabinet-maker and industrial designer with a diploma from the Ecole Nationale Superieure de CrŽation / Les Ateliers in Paris.

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