Make XXL Extensions to Create a Large Square Dining Table

The goal ? Being able to transform a 220x85 cm (86x33 inches) table into a giant square table measuring 220 x 220 cm (86x86 inches) ! But without adding feet that could bother the guests’ legs!

The current table is solid oak with a central leg, it is very heavy and will provide a good base for the project.

The idea: create 2 extensions on the long sides of the table, removable extensions, and hollow to limit the weight (slat structure and 10mm CP in sandwich).

These extensions are placed on steel tubes, themselves inserted into a larger tube, fixed under the table.

Material used: (some links paid by Amazon)

• Square steel tube 35x35mm x1m (x2)
• Square steel tube 30x30mm x2m (x2)
• Steel plate 30x4mm x1m
• Set of 6 planed fir strips 27x47mm x2m
• Planed fir strips 27x47mm x2.5m
• Plywood panel, Thickness 10 mm 220x67cm (x4)
• Pack of 10 star head knurled screws M8 x 50 mm
• 25 Threaded Nuts M8x20
• Set of 4 caps for square tube 30x30mm
• Box of 40 hex head lag screws 6x60mm

As my translation is surely approximate, I will provide you with links to a French store so that you can see better for yourself with photos.

Because it's clearer to see how to do it, here are all the steps in video.

For the plans, I started by modeling the project with Fusion 360, then I produced side plans.

PDF plan attached.

The goal being to make lightweight extensions that are easy to transport, there is no question of using solid wood.

These extensions are therefore hollow, made up of a batten structure, surrounded by 2 plywood panels.

So I used fir battens with a section of 27x47mm. They are cut 4 by 4 with a miter saw, then assembled with 4.5x60mm screws.

I didn't make a pilot hole because I used an impact driver.

For the boards I used 10mm thick plywood. I had them cut to the right dimensions by my DIY store.

I created handles by making 2 holes of 40mm in diameter with a hole saw, then I finished with a jigsaw.

I then fixed these panels, on the structure, with screws, then nails (using a pneumatic nailer)

I leveled the edges with a cutter equipped with a ball bearing to rectify the boards that were sticking out.

I then rounded all the edges with a quarter round cutter mounted on a trimmer.

And finally I finished by sanding the whole thing.

The extensions will be placed on 30x30 mm hollow steel tubes, I cut them with a metal miter saw.

To fix them, I drilled a 30x4mm flat iron with a drill press, then cut out sections to make fixing brackets. They are welded on each tube.

Once the tubes were thoroughly cleaned with acetone, I painted them ironwork black.

To create the blocking system, I am not very equipped to work with metal, so I used pieces of square tubes, which I opened on one side to create the necessary shape.

I added heat shrink tubing to make it prettier and secure better.

A system of knurled screws and nuts allows the tubes to be easily dismantled and reassembled.

PDF plan attached.

These blocking systems are fixed under the boards with threaded nuts.

Everything is ready ! The set is made up of 2 extensions, 2 tube supports (which will be fixed under the table), 2 tubes, and 4 locking systems.

I marked the location of the supports, I made a pilot hole, then I fixed them with 6x60mm lag screws.

I took the table top apart and turned it over to make it easier to work with.

For assembly, simply slide the 30x30mm, 2 meter long steel tubes into the supports, place the extensions on top, then block them with the locking systems.

It is very solid, you can lean on it without problems, the table is not likely to tip over.

I also cut 2 tubes shorter, allowing us to only use one extension if we don't need both.

When you don't need them, they are easy to store in a corner of the garage.

This is a large square table that can accommodate up to 16 guests!