Whether you do woodwork as a professional or hobbyist, some projects may require attaching separate boards of wood along their perimeter to make a larger one. For this reason, you need to know how to join two boards lengthwise.

There are many ways to attach separate wooden boards, even though using wood glue may be popular. Each of these techniques comes with its own complexity, advantages, and limitations.

That said, here is a rundown of the various methods available for joining two boards of wood lengthwise.

How to Join Two Boards Lengthwise

You can use wood glue, metal straps, dowel joint, kreg jug, tabled lamp joint, half lamp joint, and bevel cut scarf joint to join two boards lengthwise. Gluing is the commonest method, so you may opt for it as your top choice. Apply the glue to the ends that need to be attached and clamp them.

How to Join two Pieces of Wood Lengthwise in 8 Ways

Let’s explore the eight ways of joining two pieces of wood side by side.

1. Wood Glue

As already mentioned, gluing wooden boards together is the commonest method. It entails applying the glue to the ends that need to be attached and clamping them together until the glue dries and bonds the boards together.

Supplies for edge joining boards

  • High-quality wood glue
  • Clamps
  • The boards to be joined
  • Chalk
  • Chisel

How to join two boards with wood glue

  • Place the boards on a plane surface side-by-side, preferably in perfect alignment with grain patterns.
  • Use chalk to draw a big U shape covering both boards. The U shape will make it easier to realign the boards after applying wood glue.
  • Apply wood glue to the edge of one board by running a continuous bead along its entire length. To do this, position the board with the side to be glued facing up.
  • Join the edges observing the chalk mark to guide you, push them together, and clump them up.
  • Let the bond set for 20 minutes, and then clean away the excess glue by scraping it with a chisel.

2. Metal Straps

Metal straps are an option when you are not looking for a clean joint. The straps work by holding the boards together and remain visible on the boards’ surface.

Supplies for joining two boards together

  • Metallic straps, about ¼-inch thick
  • Duck-billed scissors or tin snips (optional)
  • Your two boards
  • Drill bits
  • Screwdriver
  • Screws
  • Pencil

How to join boards together with metal straps

  • Cut the straps to correspond to the width of the boards
  • Glue and screw half of the strap onto one board, leaving half of it protruding for the other board
  • Clamp the board to the strap and let the setup stay for 20 minutes
  • Align the edge of the second board to the first, and then glue and screw the protruding half of the strap to it
  • Clamp the second board to the strap
  • Keep the setup on a flat worktop while it dries for the best results

3. Dowel Joint

This method involves inserting dowels into the boards at the attachment point for added strength. The dowels provide material support and help create a sturdy, more flexible joint.

Dowel joints are popular in woodworking because of the proven effectiveness of the technique. To use this method, here are the supplies you will need.

Supplies for joining boards side by side

  • Wood dowels (pre-cut)
  • Pencil
  • Depth gauge
  • Clamp
  • Wood glue
  • Ruler
  • Drill bits
  • Mallet

How to connect two pieces of wood with dowels

  • Mark the dowel points at equal intervals along the inside edge of each board with a pencil and ruler.
  • Set a drill bit to the size of the diameter of the dowels and drill the first hole to about half the length of the dowel.
  • Remove the wood dust and test the dowel. It should be close fitting so that you can tap it into the hole with a mallet.
  • Adjust the drill bit if necessary and complete drilling all the remaining holes for both boards.
  • Insert all the remaining dowels into the holes on the first board.
  • Cover the exposed ends of your dowels with wood glue.
  • Align the two panels with the second on top of the first so that the exposed ends of the dowels enter the holes on the second panel.
  • Press the two boards together to close the gap between them, then clamp them until the glue dries.

4. Biscuit Joiner

A biscuit joint uses tiny wood plates resembling biscuits to attach wooden boards. The technique involves creating tiny slots inside the edges of the two panels to be attached. The biscuit-like plates then enter these slots to create a clean joint.

To create biscuit joints, you will need a few specialized tools and a bit of skill. That said, here are the tools and materials you need.

Supplies for joining two boards end to end

  • Clamps
  • Tape measure
  • Biscuit pieces
  • Biscuit joiner tool
  • Pencil
  • Spray bottle with water

How to connect two boards together with biscuit joints

  • Line up the panels against each other and identify the locations to place the biscuit joints at equal intervals
  • Mark these locations with a pencil
  • Next, stand the wood boards and mark the actual spots where to drill the biscuit slots
  • Set up the biscuit joiner
  • Cut the clots with the correct settings to accommodate half of a biscuit plate in each board
  • Insert each biscuit into its slot on one board
  • Spray the biscuits with water and slot the panels into place
  • Clamp the wood boards and let the biscuits set for the recommended time

5. Kreg-Jig

This method is commonly used in professional furniture building to create joints with hidden screws. It involves inserting pocket-hole screws into pocket holes created with a Kreg jig. The holes are angled in a manner to keep the screws neatly out of view. 

The Kreg tool technique creates professional-looking results with neat and sturdy joints if done properly. However, you will need the specialized tool, which is likely to come at a cost. 

Tools & Materials for joining wood boards

  • Tape measure 
  • Kreg jig
  • Screws 
  • Clamps
  • Screwdriver 

How to attach two pieces of wood with Kreg jig

  • Measure the thickness of the board and adjust the drilling equipment’s collar to this measurement
  • Set up the guide holes appropriately and then clamp the wood
  • Place the drill into your guide holes and drill out two to three pocket-hole sets
  • Align the other panel and clamp it up
  • Insert one pocket-hole screw after another into the respective guide holes
  • Tighten the screws with a screwdriver until the gap disappears

6. Tabled Lap Joints

The tabled lap joint is a technique for attaching two planks of wood using glue and two interconnecting parts where the material has been removed.

The technique involves removing material from both boards to create an interconnecting point that forms a joint with the same thickness as each member.

For this to happen, you carve out half the thickness of each piece at the joint and apply glue on the attaching surfaces.

This kind of double technique makes the tabled lap joint pretty strong due to the large wood glue surface added to the strength of intersecting parts as in a half-lap joint.

Supplies for joining wood planks

  • Table saw, or radial arm saw
  • Dado set
  • Square
  • Pencil

How to join wood planks with tabled lap joints 

  • Use a square to position the two boards side by side to flush their ends.
  • Measure ¼ of an inch plus the width of the workpiece on both the boards and mark them simultaneously.
  • Use a pencil to mark where you will cut on both pieces with an X, then draw a line from one edge to the other, crossing both planks.
  • Install your dado set in the table saw, setting the blade height to 1/3 of the thickness of your wooden piece.
  • Next, rabbet both the planks.
  • Reset the dado blade height to 2/3 of the thickness of your wooden pieces. Use a scrap wood piece to test and adjust the height of the dado blade until it is flush with the surface of both boards.
  • Measure an equivalent of ½ the width of the wooden piece from the dado’s shoulder and mark that point with a pencil.
  • Clamp both planks side by side against the miter gauge.
  • Make passes on the dado twice to establish the width, and cut the dadoes.
  • Trim the ends of each wooden piece to make them tight-fitting.
  • Glue and clamp the wood pieces for at least an hour to set fully.

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7. Half Lap Joints

This is a method of attaching wooden planks that involves removing material from both of the boards to create an interconnecting point that forms a joint with the same thickness as each member.

The technique requires carving out half the thickness of each piece at the joint as the planks to be attached are typically the same thickness. When attached, the resulting joint is the same thickness as each board. 

Supplies for joining boards together

  • Table saw  
  • Dado set
  • Square
  • Pencil
  • Wood glue

How to join two boards side by side with half lap joints

  • Use a square to position the two boards side by side so that their ends are flush.
  • Use a pencil to mark where you will cut on both pieces with an X, then draw a line from one end to the other, running across both planks. 
  • Install your dado in the table saw, setting the blade height to ½ of the thickness of your wooden panels.
  • Check to ensure the inside edges (to be attached) are completely flush, leaving no spaces between them.
  • Cut identical dadoes on both boards with the help of a miter gauge extension along the marked line. 
  • Join the two pieces to test the fit
  • Clean away any unevenness with a wood chisel
  • Complete the work by applying wood glue and clamping the wood panels together for at least an hour
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8. Bevel-Cut Scarf Joints

This is a simple technique that utilizes the depth of an angle on the attaching edges to create a strong joint. When using this technique, you want to make the angle as sharp as possible to get a sturdier joint.

This is because the sharp angle helps create a larger surface for bonding. The larger the bonding surface, the more glue you can apply, leading to a stronger joint.

Supplies for connecting 2×6 end to end

  • Miter saw
  • A square
  • Pencil 

How to join two boards together using bevel-cut scarf joints

  • Align the two boards on a flat surface with the ends to be attached sitting flush on each other. 
  • Mark where you will cut by drawing a line cutting across both boards at an angle. 
  • Set your saw blade to a 45-degree angle and cut the board along the marked line. Do the same with the other board. 
  • Apply wood glue to the cut edge and clamp the setup in place to allow the glue to set. 

Tips on Joining Boards Lengthwise  

Knowing how to join boards lengthwise will help you get the job done. However, having a few extra tips handy can improve the quality of your outcomes. So here are a few to keep in mind when approaching the exercise. 

  1. Use strong dowels whenever you can to support the joint. Whether they are wooden or metallic, dowels provide extra support going inside the boards and making the joint more structurally sound.  
  2. Make the bonding surface as large as possible. Tabled lap joints, bevel-cut scarf joints, and dowels are all examples of methods that increase the bonding surface without altering the boding location.
  3. Keep the straps as simple as possible when using the strap method to get seamless wood joints. 

FAQs 

What is the best way to join two pieces of wood?

Mortise and tenon is the best way to join two pieces of wood together. This classic technique increases the gluing surface and creates the strongest, neatest joints for wood by inserting a section of one piece into the other.

How to join two pieces of wood lengthwise with screws

To join two wood pieces lengthwise with screws, use a Kreg jig to create pocket holes and insert the screws into the holes. This method involves angling the holes in a manner to keep the screws neatly out of view. 

What is the strongest method for joining two pieces of wood together?

Mortise and tenon is the strongest method for joining two pieces of wood together. The method involves inserting the tenon portion of the joint (working as a peg) into the Mortis (working as a slot where the peg is inserted). 

How do you connect 2×4 side by side?

Joining 2×4 together side by side involves applying an even bead of glue to a selected edge of the boards and pressing the edges together. After that, you need to clamp the pieces together and drive screws through their pilot holes. Finally, remove the clamp to complete the task.

When joining 2×4 end to end, ensure the edges of the boards are smooth and free of splinters or rough spots, or the joint will also be weak

How to join two pieces of wood with brackets

To use brackets, position the metal strips on top of the bards with the holes in them directly corresponding to the pilot screw holes. Fit the L-shaped brackets directly into both corners of the boards, and drive the screws in.

How to attach wood planks together

To attach two wood planks together, apply wood glue on the inside edge of one of the planks to be attached, then push them together and clamp them until the glue fully sets to create a strong bond.

How to Join Two Pieces of Wood Together Side by Side Summary

As long as you are in woodworking, you will want to learn how to edge join boards at some point. Knowing various ways to achieve this outcome can help you use the best technique for each project. 

We hope this guide was informational. If you have any thoughts or comments, we will be delighted to hear them in the comments. 

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