How to build a one-piece folding picnic table out of 2×4 lumber

This folding picnic table also has an optional ‘clip-on’ piece that adds to the height of the backrest when the unit is in bench mode.

The ‘clip-on’ actually adds somewhat to back comfort and (depending on taste) gives the bench more appeal.

I have tried to make this project as easy as possible, taking feedback into consideration.
This is a more simplified version with better explanations and loads of photos and drawings.

• Product
• Specification

One-piece folding picnic table out of 2×4 lumber

$5.00

Plans for a folding picnic table of 2×4 (50×100) wood that can folds down to a single bench seat. It is made solely out of 2×4 (50×100) wood

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BuildEazy

Pages 35

The size of the thing

In picnic table mode the overall footprint (area it takes up on the ground) is 60″ (1524mm) long by 47-1/4″ (1200mm) wide.
In bench seat mode the overall footprint is 60″ (1524mm) long by 21-1/2″ (545mm) wide.
The height is 29″ (737mm)

It is built using one wood size only – 2×4, a very common stock size.
The bench arms that have adorned the other models have been done away with as it is excess work, excess materials, and when in picnic table mode it is better without them.
This complete unit is built solely out of standard 2x4s (which measure 1 1/2 x 3 1/2 inches, actual size).

All the pieces can be cut from 9 only 8ft lengths of 2×4. Pretty common stuff.

What’s in this content

There are plan drawings, there’s a shopping list, a cutting list, there is a diagram showing how to cut the pieces from 9 only 8ft lengths of 2×4 to minimize waist, there is a diagram of every single piece with the dimensions, and that is followed by step-by-step instructions with plenty of pictures.

The measurements

The measurements in this project are given in both inches and millimetre. The inches are given first followed by their metric equivalents in brackets – for example: 2×4 (50mm x 100mm).

Don’t be confused by ‘nominal’ (in name only) dimensions when you buy the wood.
It is called 2×4 but it really measures 1 1/2 x 3 1/2 inches (thickness and width)

The metric equivalent of 2×4 is 50mm x 100mm, which really measures 1 1/2 x 3 1/2 inches (38mm x 89mm), actual size when dimensioned or dressed.
In short – The actual, real size of the wood (thickness and width) used in this project is 1 1/2 x 3 1/2 inches (38mm x 88mm).
If you want to use a different thickness wood or change the length of the table refer to ‘Changing stock size and/or table length’ in the appendix at the end.

Shopping list

Here is the total materials you will need.

9 only 8ft (2.44m) lengths of 2×4 (50mm x 100mm) dressed (dimensional) lumber.
• 4 only 3/8″ (10mm) bolts 3″ (75mm) long with washers and self locking nuts.
• 80 only 3″ (75mm) exterior type wood screws.
• 2 only angle brackets (sliding door stopper type brackets).
• 6 only galvanized 6″ (150mm) nails.
• Exterior wood glue.

Note: There is no material allowance for the ‘clip on’ piece as that is optional and only and idea that you yourself might want to change to suit.

Tools you will need

• Circular power saw  
• Drop saw (chop saw) – able to cut accurate angles 
• Jigsaw  
• Electric drill 
• Hammer
• Hand saw
• Measuring tape
• Pencil,
• Square screw driver
• Level
• Clamps
• Adjustable angle bevel  
• 3/8″ (10mm) drill bit for the bolt holes  
• 1/8″ (3mm”) drill bit for the screw holes  
• 1″ (25mm) drill bit to countersink (embed) the bolt head

Part identification – Schematics

The plans

Side elevation plans – picnic table mode

Side elevation plans – bench seat mode

Footprint plan

The individual pieces

Step 1. Mark and cut the pieces

General

Skim read through all the pages before commencing the project to see exactly what’s here and to get a general understanding of the content.
Read each step to the end before you do anything and compare the images with the text.

You can jump to any page via the ‘Table of Contents’ on the right side bar, or beneath the content if viewed on a mobile device.

Pre drill all screw holes.

Step 1. Mark and cut the pieces

Mark all the pieces onto 9 only 8ft (2240mm) lengths of 2×4 (100mm x 50mm) as shown in the drawing below. Refer to the individual pieces plan on the previous page for the dimensions of each individual piece.
Place a sticker on each marked piece. Write the piece identification number on each sticker for future reference.

Cut the pieces out, don’t bother with any round cuts at this stage – just square cuts and angle cute.

Go to the next page for angles pattern.

Note: All the wood in this project is of dressed (dimensional) 2×4 (50mm x 100mm) stock.

But the real, actual size of the wood measures 1 1/2 x 3 1/2 inches (38mm x 89mm).

In short – The actual, real size of the wood (thickness and width) used in this project is 1 1/2 x 3 1/2 inches (38mm x 88mm).

The angles pattern

There are three different angle cuts required for this project – 10 degrees, 15 degrees, and 30 degrees.
If you want a pattern for the three angles, click on the image below and it will open up in a new window and bigger size. You can then print it out.

Once you have printed the angles pattern out, fold it over a table and then use the pattern to set your bevel to the angle you want, as in the picture below.

Step 2. The round cuts

Make a card template for the round cuts and bolt holes.
Using a compass draw a circle with a diameter of 3-1/2″ (88mm), which is the width of the wood.
Cut out the circle and that is your template.

Using the template, mark and cut the round shapes on pieces [a], [e], [f], and [g] as shown in the pictures below.
Each pair should be a mirror image of one another.

The middle of the template will mark the center of the bolt holes.

Step 3. The bolt holes

Each bolt hole will begin with a wider starter hole to embed (countersink) the bolt head or nut.

Drill a 1″ (25mm) starter hole the depth of the bolt head and washer ON ONE SIDE ONLY of each relevant piece. Then continue through the wood with a 3/8″ (10mm) hole.

Now listen up – this is important: There are two of every piece and each pair mirror one another. Hence, the starter holes must be on opposite sides of each matching pair. Simply follow the pictures below and take note of what side the starter holes are on.

Pay particular attention to the hole placement in piece [g]. Refer to the plan drawing below.

Step 4. Make up the back seat side-frames

Make up the two back seat side-frames.

Assemble both back seat side-frames as shown in the photo and as per plan below.

Fix horizontal pieces [d] and [e] to pieces [b] and [c] with screws and exterior wood glue. Use 2 screws per meeting. Pre-drill the screw holes through the horizontal pieces.

The frames must mirror one another as shown in the picture. Take note (from the picture) of which side (of piece [e]) the starter hole is on.

Ensure that the bottoms of pieces [b] and [c] and the horizontal pieces [d] and [e] are parallel.

Step 5. Make up the front legs

Make up the two front legs consisting of pieces [a], [h], and [h1] so they are a mirror image of one another.
Use the plan below for placement and the pictures below for guidance.

Step 6. Join the table rails to the leg extensions

Join the table rails to the leg extensions to make up the third and final component of the frame mechanism.

This consists of pieces [g], [f], and [f1].
Make up two according to the plan and picture below. They must mirror one another.

Step 7. Assemble the side-frames

Assemble the two side-frames (the working mechanism) as shown in the plan and picture below. The side-frames must be a mirror image of one another.
This is really just a matter of aligning the bolt holes, threading bolts (with washers) through the holes, and applying washers to the other ends followed by nylon locking nuts.
Tighten the nuts tight enough to allow the frames to fold, but not loose enough to allow sideways wobble.

Step 8. See if it works

While on the ground, test the folding motion to ensure that the mechanism works as is intended.
When you fold the frame to seat mode with the top of the horizontal seat members [e], [f], and [h] all flush, check that the bottom of the tabletop rail [g] is at least flush (vertically) with the top of the back leg [c]. It doesn’t matter if it protrudes a little bit past.

Step 9. Prepare for the seat boards

Prepare the side-frames to take the seat boards.

Fold the side-frames over (into seat mode) until the tops of the horizontal seat members [e], [f], and [h] are flush (even), place a piece of cardboard packer between pieces [f] and [h] and then apply a clamp to each side frame to hold it in that position.
Then place the side-frames apart and parallel in readiness for the seat boards.
You might have to place a little packer under front legs [a] to balance the frames.

The cardboard spreads pieces [f] and [h] apart a little bit to help ensure the frame doesn’t bind during the folding motion.

Step 10. Add the seat boards

Place the seat boards in place on the side-frames. It should be obvious which boards go where.
The shorter seat boards [l] fit in between pieces [f1] with the back edge flush with the back of piece [g] and the longer seat boards sit flush with the front and ends of the frame.

Fix the front boards first and then the back boards ensuring everything is square and plumb . Fix with screws. At this stage do not use glue in case any adjustments are needed. You can unscrew, glue, and re screw at a later time when you are sure the mechanism is working properly.

Step 11. Add the tabletop boards

Refer to the drawing above and add the tabletop boards as follows:

1. Fix board no.1 and board no.5. Make the overhang at each end equal.
Board no.1 starts flush with the end of piece (g). It can be glued and screwed in place.
Board no.5 is temporary, just to keep the tabletop rails (g) parallel. Screw but do not glue.

2. Fix (with glue and screws) boards no. 2 and 3. Then take off board no. 5.

3. Whoa, hold it there. Time to fasten the tabletop boards in the middle to stop possible wrapping which could make for an uneven tabletop. Read the next step ‘Step 12. Keeping the tabletop boards even’. Apply that method to the three tabletop boards already fixed in place, and then add boards no. 4 and 5 securing in the same manner, as you go.
Leave the unit in that position, with the clamps still on, until the backrest stops have been fixed in place as explained in step 13.

Later, once the unit is in picnic table mode (towards the finish), you can fasten the middle of the seat boards in the same manner as you fastened the tabletop boards.

Step 12. Keeping the tabletop boards even

This is a method I have found very effective (in this scenario) for keeping the tabletop boards and the seat boards even in the middle. Simply nail 6″(150mm) galvanized nails through the edge of one board into another.
Pre drill the hole first the full length of the nail and the same diameter as the nail.
Make sure the nails in the tabletop are staggered, to ensure one nail does not run into another. See the pictures below.

Step 13. Add the backrest stop

With the unit still on it’s knees (so as to speak), and the clamps still holding everything in place, now is the time to fix the backrest stops.
Fix one to each rear leg (c) up against the side of the tabletop (currently clamped in seat mode).

Now you can stand it up, take the clamps off, take out the cardboard packer, and open it out to picnic table mode…

But wait!!! There is nothing to stop it from spreading out too far. We need a spread stopper.

Step 14. Stop the table from spreading

We need a spread-stop (for lack of another term). Otherwise the table will just keep spreading out until it is on the floor.

O.K. Open up the picnic table until the from leg and back leg are 47-1/4″ (1200mm) apart overall.
Find two pieces of wood (or something) slightly longer than 47-1/4″ (1200mm) and clamp them to the bottom of the front and back legs, one each side of the picnic table. That will hold the table in position and stop it spreading while you fix the spread-stops.

Apply two spread-stops each end. Spread-stop 1 and Spread-stop 2.

Spread-stop 1 is piece (g1). There are two, one each end. Fix them (g1) to the ends of the tabletop rails (g)so they are positioned flush with the ends of the tabletop rails (g) and against the front legs (a). Fix with glue and screws.

Spread-stop 2 are angle brackets (sliding door stopper type brackets). Fit them to the front legs (a) as close to the outside of the leg as possible and hard up against the end underside of the tabletop rail (g). Ensure it is as close to the outside of the leg as possible otherwise it could be in the way when folding the table back to bench mode.

Step 15. Add the seat braces

Hey, almost there. Just the rear seat to brace.

Turn the table upside down and prop or sit the rear seat on something solid. Ensure that the seat side-frame and the seat are at right angles to each other and fix the braces (i) in place. Just like in the picture.

Flip the folding table up the right way and see how it works.

Step 16. Well done

Yes, well done. If you have made this folding picnic table to the dimensions given in this content, and you have followed all the instructions thus far, you should have a unit that looks like this

And if you want to add a back-rest clip-on (as shown below) for a bit of extra back comfort and also to give a more appealing look (depending on taste, of course) to the unit when in seat mode, then go to ‘Appendix 2: The back-rest clip-on’.

Appendix 1: Changing stock size and/or table length

It is possible to use a different stock size (thickness) and/or change the length of the folding picnic table.

Using a different stock size (thickness only)

If you want to use a wood that is slightly thicker or thinner that the wood size used in this article, you must adjust the length of the four bolts to suit as well as apply the formula (see below) to the seat boards and the tabletop boards (in relation to one another).

Changing the table length

You can change the length of the table simply by changing the length of the seat boards and tabletop boards.
The same amount must be added (or subtracted) to the back seat boards, the front seat boards, and the tabletop boards.
If you use a thicker or thinner wood as well, then you must apply the formula.

The formula

The difference in length between the shorter and longer seat boards is the sum of the thickness of four side framing members plus 1/4″ (6mm). The later measurement is to allow for a little bit of play.
For example, if the side frame members are 1-1/2″ (38mm) thick, four times that plus 1/4″ (6mm) equals 6-1/4″ (158mm).
Therefore 6-1/4″ (158mm) will be the difference between the length of the front and rear seats boards.

The difference in length between the tabletop boards and the longer seat boards is the sum of the thickness of two side frame members plus 3″ (76mm) for the overhang (shared equal each end).
For example, if the side framing members are 1-1/2″ (38mm) thick, two times that is 3″ (76mm), and plus the 3″ (76mm) overhang = 6″ (152mm).
Therefore, In that case the table boards will be 6″ (152mm) longer than the longer seat boards.

Appendix 2: The backrest clip-on

A backrest clip-on if you want to make the backrest a bit higher for comfort or looks.

You will need:
• 1 piece of 2×6 (50mm x 150mm) that is 60″ (1524mm) long.
• 4 pieces of 2×4 (50mm x 100mm) that are 10″ (254mm) long.
• A dozen 3″ (75mm) screws and a bit of glue.

Make the clip-on up according to the following plans and pop it on top of the backrest when the picnic table is in bench seat mode.