Demountable-Expandable Table

Hello everyone, I want to show you this table that I designed and built, I wanted to do something a little different, and after many sketches on paper I got something that I liked,

I wanted it to be a large and sturdy table, but despite this is not very complicated to transport it, with this in mind I tried to make it dismountable, and something I also wanted to try is to make an expandable furniture, so this was also the opportunity to try it. Thinking about materials... I really like the combination between wood and steel, so I definitely applied it here

Well, this is how i did it.

PS. Sorry but my english is not the best, I will try to explain as best I can :)

Materials

- 15mm Plywood

- Wood planks

- Steel square bars (3/8")

- Steel flat bars (1" 1/2)

- Tee steel bar ( 3/4")

( These are the materials that I used in more quantity, the others I will show as I explain)

Power Tools

- Welder

- Circular saw

- Angle grinder

- Drill

- Router (opcional)

This is the basic idea, four wooden legs (C) that are joined to the metal structure (B), this structure is joined in the center, when it is disassembled it can be folded.

Above this is the tabletop, which is divided in half (A1 & A2) each one is attached to the metal structure with a rail, which facilitates its assembly and disassembly. Each of the two boards has an internal rail allowing its upper half to move and increase its surface. (approximately 35% more in total)

P.S. I used mainly the metric system, but I will mention some things in inches because that is how it is sold locally (bits, some materials, etc).

For the legs I used a wooden plank 20 cm wide and 3.5 cm thick. I drew the pattern on the wood looking to save some cuts.

The legs are attached to the metal structure with two screws each, I will make the holes later taking as a reference the metal plate that presses them.

The first thing is to use the plywood to cut the different panels, the drawing represents the four pieces that form one half, the width I used was 90cm.
Some pieces have an inclined cut, they are 55 degrees (the maximum that my circular saw allowed), basically it serves to easily move the upper panel over the lower one when you want to expand the table. At that time I tried it and that inclination is enough so that the top panel can easily go up and down.

With wood glue I joined the two parts of the lower panel.

This is the easiest, the upper one has more parts ;)

The upper panel by itself can move over the lower one, but it needs something that gives it a little more stability when expanding the table, this is where I use the tee, this profile does two tasks:

1. It will serve as a rail to place a spring that holds and maintains both panels together, but without losing the ease of movement between them. 2. It will serve as a "core" that keeps the plywood panel rigid, preventing it from bending under its own weight.

This step is a bit tedious, first I need to cut a part of the tee so that it has the same measurement as the thickness of the plywood, so that it does not hit the bottom panel. Now it is necessary to make a groove with the grinder where the spring can move. The other end of the spring will hold onto the bottom panel.

I made two for each panel.

To embed the tee in the plywood it is necessary to make some cuts and grooves.

First I made a groove of the same thickness as the tee with the router, so that it can be flush with the board, then in the middle of this groove I cut the board into three parts to be able to embed the two tees. Along the entire length where the spring is displaced, I widened the cut a little more.

Now to rejoin the board with the tees you have to do a few things.

First, so that all the parts are well joined, I had to improvise some small plates with a hole, which I welded to the bottom of the tee, in this way the boards can be joined and fastened with a screw. Once this is done, we can glue it together with the smaller board, as it was done in the lower panel, of course, first you have to make a groove for these plates, so that both boards can be glued correctly.

With this we begin the main steel structure, these "arms" are basically trusses that are joined at one end to a mobile core, the objective is that it can be folded when the table is disassembled. In the following steps I will explain the moving parts it has and how they hold the countertop.

These trusses are made with the square bar, it also has a plate that is where it will be screwed with the wooden leg. It is important to make the pieces precisely, these arms must be as exact as possible to avoid future problems. I made some templates with the necessary pieces and I was cutting each one of them, then I drew the pattern of the entire truss to weld everything together.

Now it is necessary to cut a steel plate to weld it inside the truss, measuring the truss I made a template, the plates I cut from some scrap metal that I had at home, it is convenient that this plate is at least 3mm thick.

Once this was done, I welded them to the trusses on their inner side, in this way when we place the legs they can press them properly.

With the welded plates we can finish the "arms", now we have to join two pairs of trusses, everything must be very well aligned, the separation between each one will depend on the thickness of the legs.

When it is finished we can make the holes taking each of the legs as a guide, so there will be no mistakes when we assemble everything.

This core is the one that joins the four arms, each of its ends has a steel axis that allows each arm to fold, also in the center of this core there is another axis that allows everything to fold.

That is the basic idea, the final result does not look much like the drawing but I hope it serves as a reference at least. I cut each of the necessary pieces from the flat bar. For the central axis I adapted a type of hinge that is used for heavy loads, the other axes are 1/2 "rods and at their ends I weld a pair of washers so that it is fixed and can rotate easily.

With these finished parts we can join the arms with the core and check how it can be folded.

As I said, this table should be able to be dismantled, this is where a rail is included, which joins the arms with the countertop, there are two parts, one is attached to the arm and the other to the lower panel. With this rail you can place or remove both panels.

These pieces are not completely immobile, they can rotate around an axis in each of the arms, this must be so because the conuntertop must enter longitudinally and the legs have an inclination towards the center, so when they rotate they can be accommodated to place the countertop and then relocate them to their normal position. For this I used the flat bar and the square bar, I welded them a 1/2 "steel rod and to hold everything in place and allow them to rotate I welded a washer to one end of the shaft, just like the core.

Now we can place the legs, we do it to verify how everything is located, I joined them with a threaded shaft and a nut at each end, with this ready I can put the lower rails, they are joined at a single point so that they can rotate correctly.

I joined the other part of the rails to the bottom panel, making sure that it fits perfectly with the rails on the legs.

These are also joined at a single point because the entire set of rails on each leg must rotate at the same time. They are fixed at one end by welding a washer to it.

I added a flat bar to the edges of the countertop for some reasons, this bar will serve as an extra guide to the top panel and prevent it from moving transversely, also on the short side of the countertop this bar protrudes a little below, which makes it easier to pull the panel to expand it, and as an extra it also covers the inside of the panels.

To make the center of the entire countertop a little more rigid, it is necessary to add a reinforcement, it can be elements that fit together such as adding some steel rods at one end of the panel, so that when they are put together they fit into holes in the other half.

At another point, the finish in my case I left it, let's say "natural", at first I thought about painting the entire structure with matte black paint, but when I saw it assembled I liked how it was, with the steel a little rusty, in the future maybe I'll paint it.

Another detail is the core, I think it can be simplified much more, or even omitted, it is not an absolutely necessary element, but at least in my case I wanted it to be folded, currently it works very well, but it would not be bad to add a little thickness to his parts.

Well, in general I think there are many things that can be improved, I'll keep thinking and in the future maybe I'll build a second version.

For now I am very happy with the result!

This is the result, I hope you like it and perhaps it can serve as a guide or inspiration.

Thanks!