How To Join Two Boards Lengthwise

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If you are a beginner-level woodworker, you need to keep in mind that there would be numerous times where you will have to join two boards in accordance to length. And that will be your testing time because the process is easy, but you will need proper knowledge and skills. Most woodworkers think that gluing two pieces of wood is all they need to join two boards.

But it is not the case! It demands accurate implementations, such as seeking reinforcements for the joints, to ensure they are durable and sturdy. 

How To Join Two Boards Lengthwise

According to length, you will primarily need to utilize the long-grain edge of those boards when you want to join two boards. However, you can ignore the end-grain side of the boards. There are various methods of approach for you to join two boards together as per length.

Man marking his wood pieces while working on a project

Now, it is on you to choose what suits you best as per the convenience and ease of the job. So, go through this guide to get an idea of all the methods of joining two boards lengthwise

Method 1: Joining The Two Boards With Wood Glue

The most accessible and most convenient approach for all the woodworkers is to use wood glue. Here, you will need a solid bead application of wood glue, so make sure you have enough of it. Let’s hop onto the steps:

Step 1: Arranging And Marking Of The Boards

  1. Place down the boards over a flat surface. 
  2. Match the shades and wood grains as per desires. 
  3. Check for the alignment of the boards, and consider re-configuring them to meet the exact requirement. 
  4. Draw a wide ‘U’ across the alignment of those two boards. These marks are essential for re-aligning the boards after applying wood glue. 

Step 2: Apply The Wood Glue

  1. Hold one board from its long-end and start gluing from the side that is facing up. 
  2. Apply a thick bead of wood glue on continuous flow over the edge, across its length.
  3. Don’t apply an excess bead of glue that might result in spilling out of the adhesive on the realignment. It is because the edges are thin.
  4. Aim to expect no glue residues, as it might make it difficult for you to clean it out later. 

Step 3: Re-Align And Clamp Them

Wood pieces stacked on top of each other
  1. Follow the chalk or ‘U’ guide, and slide the two board pieces together. 
  2. Re-align them with ideal consideration.
  3. You will notice some of the wood glue spilling out. No worries. Go ahead and remove the glue before it dries. 
  4. Let the joint dry for around 20 minutes.
  5. Now, you can use a wood chisel to smoothen up the glue remnants. It is to ensure that the joint is invisible and perfect. 

Here is the demonstration, how you can perfectly glue two pieces of boards according to the ideal length. Follow this YouTube video link

Method 2: Joining The Two Boards By Biscuit Joiner

A Biscuit is a thin wooden piece inserted within the joint to align the boards lengthwise. This method is not that popular, but it is still an adequate consideration. Here are the steps:

  1. Get a biscuit joiner tool, tape measure, clamp, biscuits with an appropriate size, and the boards. 
  2. Align the board first, and then mark the slots.
  3. Marking should be done in few points across the length of the aligned board edges. Make sure the markings are at an equal distance from one another. 
  4. Now, you can separate the boards and then mark the actual slot locations. 
  5. The slots should be as per the center of the previous marks. It can be long as that of the biscuit you intend to use. 
  6. Set the biscuit joiner, as per the application demand, for the cut. The slots should be half the width of the biscuits that you have chosen. 
  7. Adjust the plunge depth, and center the device before you can commence with the cuts. 
  8. Now, you can insert the biscuits after clearing out the excess dust amidst the cuts. 
Stacks of wood laid on the pavement
  1. Insert a biscuit in one of the sets of slots. 
  2. Once the biscuits are set within the respective slots, spray water to the biscuits for activating the glue or sealant within them. 
  3. Now, slide the boards with the biscuits in between them. 
  4. Align the boards, and clamp the panel, to let the biscuits settle down for few hours before applying pressure onto the boards. 

Method 3: Joining The Two Boards By Dowels

  1. You need to measure out the dowel locations using a ruler, pencil, and depth gauge. 
  2. Drill the first hole and test whether the dowel fits within the hole. Using one of the best dowel jigs to speed the process up.  
  3. Now, drill all the remaining holes and insert all the dowels. 
  4. Now, you can clamp and set the boards to let them be strong and durable. 

Frequently Asked Questions

What Is The Best Method Among These Three For Joining Two Boards Lengthwise?

The method of using dowels for joining the boards is considerably the best durable method for joining them. There is less or no chance of joint breaking out from the center. But it doesn’t mean that the other two methods are flop! The glue and biscuit joiner methods are also ideal choices for most applications associated with wood joining.

Can You Guide Me With Some Ideal Tips For Applying Wood Glue To Join The Wooden Boards?

The glue-ups are sometimes challenging and need much more precision while joining two boards for making a piece of furniture or other woodworks. Therefore, here is the article of tips that you need to check out to make the glue-ups proficient. 


Acquiring knowledge on some of the most important methods for joining two boards lengthwise will help you commence your woodworking skills. If you are a beginner, this is probably the first and foremost skill you should learn. So, follow the guide, get your tools, and take up your woodworking projects

An expert at home repair, remodel, and DIY projects for nearly 40 years. His first experience came in completely restoring an antique home. Completely redone from the inside out, and restored to its original form, the home is a featured design by renowned Southern California Architect Cliff May, considered to be the father of the California Ranch Home. Now Dennis spends his time on fine woodworking projects and tool comparisons.