How to Join Two Boards Lengthwise: 11 Best Methods

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If you’re someone aspiring to become a skilled woodworker, the significance of mastering techniques like the edge joint cannot be understated. As a seasoned woodworker, I’ll admit that it’s a skill that demands dedicated practice and training.

If you’re eager to discover how to effectively join two boards lengthwise, I’ve put together a comprehensive guide that you’ll find immensely helpful.

What is Edge Joining?

The term “edge joining” may sound unfamiliar to you, especially if you’re a beginner in woodworking. But most likely, you’re aware of what its final product looks like, which is two boards fastened together and leveled on the entire length. This connection point is called the edge joint.

Unlike other types of joints, it creates a larger piece of wood that can be used for a bigger project. Generally, edge joining boards aim to combine and align their component pieces into a straight piece of wood that is broader and longer.

How to Successfully Join Two Pieces of Boards Lengthwise in 11 Ways

Method #1: Wood Glue

The most basic and accessible way of joining two different boards lengthwise is by using durable wood glue. Essentially, you must apply a reasonable amount of glue along the length of one of the boards prior to aligning and attaching them together.

This simple method allows you to achieve a seamless weld after cleaning the excess glue. I recommend this method when making tabletops and other wood furniture that you want to look smooth and flawless.

Pros and Cons

Most DIYers and even professionals prefer wood glue due to its many advantages. Aside from a simple and straightforward procedure that you can easily follow, the materials you need are handy and readily available in your nearest hardware.

Also, wood glue is significantly cheaper. Most importantly, you don’t need specialized tools and equipment to finish your project, so you can save a lot compared to other joint types.

However, glue is considered to be weaker and may not be the ideal option for heavy-duty projects. Although you can use modern and stronger glue, you cannot put excessive weight directly or near the joint as they can only hold limited weight.

Also Read: How to Unglue Wood Joineries

Also, too much glue tends to expand while setting, so you can expect some bowing, especially when the affixed boards are not clamped together properly.

See Also: Wood Glue vs Liquid Nails

Materials You’ll Need

Steps to Do

1. Mark and align the wood boards.

Start by placing the boards on a sturdy and flat surface. Then, arrange them to ensure that the wood shades and long grain match aesthetically.

Once you have achieved your desired wood alignment, use the chalk to draw a big “U” shape across the two aligned boards. Ensure that the “U” opens downwards with the arch slants outwards along each board.

I recommend making these marks to safeguard the boards’ alignment and make it easier to rearrange them after applying the glue.

2. Apply the glue on the wood board

Now, from your arrangement, position the bottom on its side so that the edge that you need to bond faces up.

Then, proceed to apply glue along the whole length of the board’s edge joints. Make sure that the continuous bead does not exceed 3/16-inch wide so that the glue will not spill out.

3. Clamp the boards together

I followed the “U” shape I drew earlier as my guide to slide the boards back to their alignment. Once you are sure that the boards are properly aligned, use the clamps to apply pressure.

Also Read: Best Clamps for Woodworking

The pressure ensures the glue is dispersed evenly and sets consistently on the whole joint. I let the glue set and dry for 20 minutes before moving the boards.

4. Clean excess glue

It is inevitable for glue spills to come out as you clamp the boards together. Remove this immediately to avoid damaging the wood.

I also suggest to clean the glue residue after 20 minutes of setting so that it is solidified but not too hard to scratch off. Use a wood chisel to shear it off until the glued joint is tidy and almost invisible.

Method #2: Dowel Joint

This method uses dowels that are inserted into the boards at the joint point to add strength and durability. It’s no wonder this technique is popular among professional woodworkers because of its proven effectiveness. Also, it’s one the strongest wood joints you can make.

Pros and Cons

The main advantage of the dowel joint method is it does not require complex and heavy-duty woodworking tools, but the output is of professional quality. All the materials I needed was a set of decent dowel rods to finish my project faster. In fact, it is the fastest kind of joint to make.

However, this technique requires precise measurements. So, if there’s any inconsistency in your measurement, you will not be able to achieve your desired output.

Therefore, I suggest you practice with some scrap wood first before you proceed, especially if you’re using expensive wood for your project.

Materials You’ll Need

Steps to Do

1. Measure the dowel locations

To start, I measured out the dowel locations. Use the depth gauge, ruler, and pencil to label the series of points at equal distances. Ensure that the points are proportionate with the width of the boards and the size of the hole dowels.

Make sure you double-check the measurements because even a slight difference can result in an uneven board joint.

2. Drill a hole and test

Use a drill bit with the same diameter as your dowel rods. Then, put a masking tape strip around the bit up to half of the dowel’s length and attach it to the drill. Proceed to drill a hole and test if the dowel fits. Aim for a tight snug then pound it with a mallet.

3. Insert the dowel rods

Once you are sure that the measurement is precise, drill all the remaining holes. Then, insert the dowel rods in a secure and efficient manner.

4. Clamp the boards

I like to apply an adhesive or glue on the dowels, although it’s only optional. Now, slide the board without dowels into the board with dowels then connect the drilled holes. Use the mallet to apply extra pressure.

Once the boards are connected, mount them into the clamps and allow several hours to set properly.

Method #3: Plywood or Metal Straps

I recommend this method if you’re not particular about the clean and seamless-looking joint. The metal or plywood straps technique work by supporting the wood panels together but remaining visible on the surface area.

Pros and Cons

A strap joint is one of the easiest techniques to join boards lengthwise since you do not need specialized tools. Also, I find it most suitable for beginners and DIYers as it does not require expert skills. Most of all, it’s cheaper so you can save a lot using this technique.

However, the output is not necessarily aesthetically pleasing since the joint is exposed. Therefore, I don’t recommend joint straps for polished furniture or any project intended for display.

Materials You’ll Need

Steps to Do

1. Cut the straps

First, you must measure the width of the two boards. Ensure that the strap is the same size as the panels. Then, cut them accordingly.

2. Glue and screw the board

Put glue on the other side of the strap, then screw it to one panel. Make sure to leave half of the strap protruding to be attached to the other panel. Then, clamp the panel into the strap and allow 20 minutes to set properly.

3. Set and dry

Align the second panel to the one you worked on earlier, then apply glue on protruding portion of the strap and screw it to the second panel. I suggest applying pressure on it using the clamp and leaving it on a flat surface to dry completely.

Method #4: Kreg Jig

This method is commonly used by professional woodworkers for customized home furniture, such as desks and tables. Essentially, this technique uses a Kreg jig to create an angled pocket hole where a screw will be inserted.

Interesting Read: How to Raise Your Desk’s Height

The holes should be angled perfectly to hold the boards together and keep the screws hidden. Consequently, you can expect the Kreg jig joints to be sturdy, very neat, and professional-looking.

Pros and Cons

This method is one of the most sturdy types of board joints due to the strategic angle they’re attached to and fastened by a strong metal screw. Though it seems complicated at first glance, it’s easy to make if you have a proper tool.

On the other hand, the tool requirement makes it less appealing among DIYers or beginners. Although you can easily purchase pocket-hole tools, there’s not much use for them other than this project.

Also, jig tools must only be used on sturdy hardwoods that can endure the lateral pressure produced when drilling the hole. This may also require a lot of practice before you can create an angled hole, especially if you’re unfamiliar with pocket-hole tools.

Materials You’ll Need

Steps to Do

1. Measure depth collar

I started by measuring the width of the boards. Follow the measurement to set the depth collar, ensuring that the hole has the same depth.

Use the measurement chart attached at the base of the jig as your guide. Adjust the measurement as necessary and ensure to raise the appropriate guide hole when you position the holes.

2. Clamp and drill the boards

Once the measurements are precise, start to line up the boards following the correct guide hole, then clamp in the board. Proceed to drill into the hole and make at least two sets of holes to support the joint’s maximum stability.

3. Attach the joint with screws

After drilling all the pocket holes, I aligned the boards accordingly. Then, clamp the boards and insert the screws into the pocket holes. Ensure that the screws pierce the other board going through wood fibers, then use the drill to flush the screw head in the holes.

Method #5: Biscuit Joiner

This method requires expertise and precision, so this is mainly for skilled woodworkers. Specifically, biscuit joiner involves creating small openings inside the boards’ edges to be attached. A thin, biscuit-shaped joiner piece is inserted into the openings to make a clean joint.

Pros and Cons

I recommend the biscuit joiner method for situations in which other types of joints are not an option. For example, it is the ideal method to join bowed-out shape bords since the joint can provide additional support on the tension point.

However, biscuit joints complicated to make and need specialized tools and materials. Also, they are not capable of supporting lateral pressure for a long period, which may cause the wood to bend when the joined boards hold great weight.

Materials You’ll Need

Steps to Do

1. Mark the biscuits’ locations

To start, you must arrange the wood, ensuring the long grain and colors look seamless. Mark at least three points at the same interval where you will place the biscuits.

For utmost precision, I mark the boards with the actual slots’ positions, and they must be the same size as the biscuits I used.

2. Cut the biscuits slots

Next, Follow the marks and start cutting the biscuit slots. Ensure that the slot size is only half the depth of the biscuit. Adjust the plunge accordingly, ensuring that the tool is on the center of the mark.

3. Insert the biscuits and let them set

Insert the biscuit into the slot. I suggest starting from the bottom board. Once all the biscuits are inserted into the slots, spray water to stimulate the sealant.

Then, slide your panel with the biscuit pieces into the panel with the slots. Clamp the panels and wait several hours for the biscuits to set.

Method #6: Half Lap Joints

This method involves attaching pieces of wood of the same size by removing the half thickness of each wood piece where they are joined. This type of joint offers a flawless and sturdy connection.

Materials You’ll Need

Steps to Do

1. Mark the wood pieces

Position the boards beside each other using a square, ensuring that both ends are leveled. Then, use the pencil to label X on the spot where the wood will be cut. Connect both ends with a line from one board to the other board.

2. Cut and join the dado set

Mount the dado in your table saw and set the saw blade height to half the thickness of the boards. At this step, I ensure the edges are fully leveled and there are no spaces in between.

Then, cut the dadoes on two panels using the meter gauge and following the marked line to ensure that they are identical.

3. Apply glue and set

Now, attach the two sets and test if they fit perfectly. Use the wood chisel to polish any uneven sections. Then, apply glue on the panels and clamp them together for one hour to set completely.

Method #7: Tabled Lap Joints

This technique involves interconnecting pieces with a wide glue surface of the half-lap joint. It’s one of the strongest joints due to its interconnecting points and large glue surface. However, I find this process long, and complicated as it requires precision.

Materials You’ll Need

Steps to Do

1. Measure and mark the boards

Arrange the boards beside each other using a square, ensuring that both ends are leveled. Measure the width of the wood piece and add ¼ inch on two boards, then mark them.

Then, use the pencil to label X on the spot where the wood will be cut. Connect both ends with a line across both boards.

2. Cut the dado set

Mount the dado in your table saw and set its blade height to 1/3 of the board’s thickness. Then, carve both boards. Once done with the first set, reset the dado’s blade height to 2/3 of the boards’ thickness.

Ensure that the dado blade is fully leveled to the board’s surface. Then from its shoulder, measure half the width of the wood piece and mark it using a pencil.

Clamp both boards in the miter gauge and pass on the dado at least twice to ensure the width’s accuracy before cutting.

3. Join the dado set

To ensure that the wood piece fits tightly, trim the edges properly. Then, put glue on the wood pieces and clamp them for one hour to set completely.

Method #8: Bevel-Cut Scarf Joints

This method is one of the simple ways to join two boards lengthwise. This type of joint involves creating a deep angle on the joining wood edges to make a seamless and strong joint.

If you want to create a sturdier joint, you must ensure that the angles are sharp. This will help to create a wider surface for the joint making it sturdier.

Materials You’ll Need

Steps to Do

1. Mark the boards

Arrange the boards on an even surface, ensuring that the ends are leveled. Then, use a pencil to mark the points where to cut the wood and draw a line across the panels at an angle.

2. Cut and join the boards

Set the miter saw blade to 45 degrees angle and cut one board following the line. Follow the same procedure with the other panel. Then, join the boards at 45 degrees angle.

3. Apply wood glue

Put glue on the board’s edge and clamp the boards for one hour to set completely.

Method #9: Spline Joints

Spline joint is a technique that creates a wider glue surface that is durable and resists flexing or bending. From my experience, most woodworkers prefer this type of joint for furniture like shelves, tables, closets, desks, frames, nightstands, and more.

1. Measure the wood panel

To start, prepare four wood plates, ensuring precise measurement. In this scenario, all the wood plates are rectangles while the joints form a triangle shape.

The two wood plates should measure 20cm X 15cm while the other two are 17cm X 15cm. Then, the four rectangles should measure 3cm X 2cm.

2. Create joints and slits

Use sandpaper to thin out and smoothen the joint base and level with the wood plates. I aimed for at least 1cm thickness for the joints and ensured the four joints had the same thickness.

Then, create two slits on the side of each plate, so you will create a total of eight slits. I made sure the slits have the same shape as the joints but I allowed a 1mm difference.

3. Assemble and put wood glue

Put the plates on a flat surface and align the slits for joint attachment. Then, soak the joints in glue and insert them precisely into the slits. Remove excess glue before they are fully dry.

Method #10: Pocket Hole Screw

The pocket hole screw is an easy method preferred by most DIYers. This method also creates a strong and sturdy joint by using a specialized tool, like the pocket hole jig, to drill a hole in an angle on the wood pieces. Then, you must use a screw to attach the boards.

1. Mount the pocket hole jig

Use a clamp to mount the wood into the pocket hole jig. Make sure that the jig’s end is leveled with the edge of the wood. Then, install the appropriate drill bit into the power drill. Adjust the collar to match the measurement of your pocket hole jig.

2. Drill the pocket hole

Insert the correct drill bit and start drilling until the jig reaches the collar. Create two pocket holes on one end of the wood, then do the same procedure on the other end of the wood, ensuring the holes are adjacent.

3. Assemble the wood pieces

Align the wood pieces on a flat surface. Use a clamp to hold the wood pieces firmly while you insert the screw. Ensure that you are using an appropriate size of screw according to the depth of the wood pieces.

I suggest using glue on the wood to strengthen the joint. Then allow one hour for it to fully dry.

Method #11: Joining Boards

It can be challenging joining boards lengthwise, but there are many ways you can seamlessly attach them. Essentially, you may bond boards lengthwise by using an adhesive, nail screw, knockdown fitting, or using a joint.

But among these joining wood techniques, most woodworkers prefer using a joint on furniture. Below are wood joineries you can easily use on your projects.

Necessary Supplies

Tips & Tricks on Bonding Boards Lengthwise

If you’re wondering how you can join two boards lengthwise more efficiently, here are few extra tips to remember that can make your job easier:

How to Join Wood Without Nails

There are many methods to join boards lengthwise without using nails, but the two most common techniques are biscuit joint and using glue. These techniques are suitable for joining long-end grain boards lengthwise.

Is it Recommended to Join Wood with Glue Only?

It depends on the purpose of your project. Generally, glue is weaker compared to other techniques and may not be able to sustain heavy weight. So, if your project requires to hold a heavier load and will be used often, I do not recommend using glue only.

Combining glue with mechanical fasteners such as screws, nails, or dowels ensures a much stronger and more reliable bond. This method can enhance the overall stability and durability of the woodwork.

How Strong is Wood Glue

Typically, glue can sustain pressure ranging from 3600 to 4000 pound-force per square inch, meaning it can be stronger than most wood. Therefore, some types of wood may fail first before the glue bond does.

Is it As Strong as a Screw?

When used to join two pieces of board, glue can be stronger than a screw. Although the screw is durable enough, it only connects the wood to a specific point.

Meanwhile, the glue holds the wood’s full length. So, if you have a larger bond surface, the joint will be stronger.

FAQ

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

The best way to join two pieces of wood is mortise and tenon joint. It is a tested technique to increase the bonding surface. It uses the method of inserting a portion of the wood piece into the other piece, resulting in the strongest joint.

How do you connect a 2x4 side-by-side?

To connect 2×4 side-by-side wood pieces, apply an equal bead of glue on one of the edges of the wood pieces. Press the woods together, then clamp them in. Finally, insert and drive screws into the holes. Allow at least one hour to fully set and dry.

How do I attach pieces of wood using brackets?

To join pieces of wood using brackets, mount the metal strips above the bards and position the screw holes adjacent to the pilot holes. Then, insert the L-shaped brackets into both angles of the boards, mounting screws through the wood.

How do I bond wood planks together?

To bond wood planks together, you must apply glue on the inner edge of the plank, then slide them together. Use a clamp to hold them until the glue fully dries to establish a strong bond.

What is the strongest wood joint?

The strongest type of wood joint [1] is mortise and tenon. Essentially, the mortise is a slit carved into one of the wood pieces while the tenon is the tab to be inserted into the carved slit. This way, the joint provides a robust and strong connection.

Which is stronger, biscuits or dowels?

Biscuits are simple and easy to make. However, dowels provide stronger joints than biscuits. The only disadvantage of the dowel is it’s meticulous to make since it requires precision.

Conclusion

Once you have learned all the friction joints or edge joining techniques, you can have various options for your woodworking projects.

I hope you were able to learn how to join two boards lengthwise after reading this guide. Although it can be challenging and requires a lot of training, be patient and continuously improve your fundamental woodworking skills.

Author
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Robert Johnson

Robert Johnson is a passionate furniture maker & carpenter, sought after for his knowledge on the craft.
You've probably seen his down-to-earth wisdom in USA Today, Bobvila, Family Handyman, and The Spruce, where he has shared commentary and guidance on various woodworking topics.

Robert is the brain behind Sawinery, where he aims to share tips, tricks, and a passion for all things carpentry.

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