Pretty much everyone needs folding chairs in their home. We may not need them every day; but we all encounter those times when we just don’t have enough seats around the table. Whether that’s a family get-together for the holidays, a meeting in the home or a party, a few extra chairs can make all the difference. Folding chairs provide us with a means to accomplish that, without the chairs taking up a lot of floor space when they’re not in use.
While there are plenty of folding chairs available on the market, most of those are metal or plastic. They do the job, but to someone who likes wood, they’re just not quite right. Wood folding chairs look much better than metal ones and can be made to match the color of the home’s furniture.
Folding Chair Mechanism
All folding chairs, regardless of the material they are made from, work on a geometric principle. From the side, the chair is a series of three levers, usually joined together by swiveling joints. The three levers are:
- The chair back and front legs
- The chair’s back legs
- The seat
The seat is the key to the way it folds. The two sets of legs cross, with the top end of the back legs being attached to the front corner of the chair and the back corners of the seat being attached somewhere around the middle of the front legs. Depending on the actual design of the chair’s operation, the chair can either be folded by lifting the front or back of the seat.
Folding the chair requires that these three levers change position. But to do so, at least one of the swiveling joints has to change. In most metal folding chairs, this is accomplished by the addition of a shorter lever between the seat and the front legs, hidden underneath the seat. This won’t work for a wood folding chair, as the wood parts need to be thicker than metal ones are.
One option is to make a track inside the lower part of the back legs. Pins on the back corner of the seat ride in this track as the seat is opened and closed. While an effective design, this one has the potential of breaking, as well being more difficult to build.
Another option is to create two swivel points, with the third, the connection between the seat and the front legs to be a pin or dowel rod attached to the front legs, that the seat sits upon. This is a considerably simpler design to build, but once includes the risk of the pin breaking, especially if too much weight is placed upon the seat. Still, it is a good option, which will work in most circumstances.
Perhaps the simplest folding chair design bypasses these problems, providing a channel for the front legs to slide in. The channel is made by two crossbars, attached across the front legs underneath the seat. Using this design eliminates the need for any sort of moving parts, other than the two swiveling joints at the front and back of the seat, simplifying the folding mechanism and the building of the chair.
Basic Chair Design
Regardless of the folding mechanism of the chair, there are some design elements that will be the same. The first of these is that the legs and seat frame will be made of pieces of wood that are 1”x 2”, preferably with that being the finished size, not the cut size. So, while it is possible to just go out and buy 1”x 2’s at the lumberyard, it’s better to buy material that is larger and then cut and plane it down to the right dimensions.
Secondly, the chair seat and back are made of ½” thick slats, nailed to the wood frame. These can be of any width, but are usually consistent. Avoid cracks between the seat slats, putting the slats tightly up against each other. This may require that the one slat be cut a bit narrower than the others to make it fit. If this is the case, be sure that the narrow slat is somewhere in the middle of the seat and not on the edge. The overall seat size should be 14” to 15” square.
Typically folding chairs don’t really have much of a chair back, just a strip or two across the top of the back, supporting the upper part of the person’s back. The reason for this is to allow the chair to fold. The back is attached to the front side of the supporting legs and the more of a back that there is, the more it limits the folding of the chair. Too much of a back and the chair won’t fold at all. So to get a chair that folds the flattest, it’s necessary to have the least amount of back. Ideally, the back shouldn’t overlap the seat at all, when the chair is folded.
Basic Folding Chair Building Techniques
Just as there are a number of different designs available for folding chairs, there are also a number of different techniques that can be used in making them. There’s plenty of room for “mix and match” in making folding chairs. For example, dowel rods can be used in place of crossbars, as both will do the same job.
While the basic method of attaching the seat and back to the framework is to overlay the wood slats used for the seat and back on the frame and nail it in place, back pieces can also be doweled in place, drilling through the frame and into the edges of the slats, then gluing a dowel in place.
The basic design also calls for a flat back; but as we all know, a curved back is more comfortable. That curved back can either be made by laminating thin layers together, using a classic “bentwood” process or the upper and lower crossmembers can be in a curve out of 2” dimensional lumber. Then fabric, woven caning or thin strips of wood can be attached vertically to those crossmembers to make the back.
In general, doweling is actually an easier replacement for making a mortise and tenon joint. Either one is applicable to making folding chairs, depending on the skill level of the woodworker and how much effort they want to put into their chairs. Crossbars can be attached to the main frame pieces via mortise and tenon, as well as attaching the chair back. Even the seat can be attached via mortise and tenon, if so desired. For the back and seat, the mortise could actually be a slot in the frame pieces, with the ends of the slats thinned down as a wide tenon to fit in that slot.
Any folding chair is going to require considerable sanding to remove sharp edges and corner that could cause scraped skin or splinters. I would recommend rounding all edges that can come into contact with the person’s skin while sitting in the chair with a 1/8” router roundover bit. Edges that do not come into contact, like the bottom edge of the seat frame, don’t need to be rounded.
The other thing that really needs rounding is the seat end of the back legs, where they attach to the front of the seat. It’s a good idea to make sure that it is rounded to the point where there will be no sharp corner sticking out past the end of the seat, regardless of what position the chair is in. Full rounding of the end is a good starting point, but it may be necessary to go a bit farther, using a belt sander or even a right-angle grinder, once the seat is assembled.
All the hinge points should have the same sized hole and use the same sized bolts for the hinge pins. Place ashs under both the bolt heads and the nuts. In order to make it so that the nuts do not come loose, without having to over tighten them on the bolts, nylon-insert lock nuts are a good idea. Adding a bearing sleeve inside the hole is not a requirement, but can help excessive wear from the bolt’s threads on the inside of the hole, especially when softwoods are used for making the chair.
Making a Folding Chair with Pins
One of the easier ways to make a folding chair, with the least geometry to have to deal with, is to use a pin or dowel to support the front part of the seat, thereby eliminating the need for one pin. That leaves only two hinge pins to deal with on each side of the chair. The pin or dowel acting as a support for the front part of the seat replaces the third hinge point, while still offering the necessary support.
As you can see in the diagram below, each side of the chair still consists of three levers for the two legs and the seat. The real difference is the lack of permanent connection between the seat and the front legs. This can make the seat a bit strange to open and fold to those who are accustomed to working with metal folding chairs, but it provides excellent support, as long as hardwood dowels, at least ½” in diameter are used for the seat rest pin.
A critical part of making this sort of chair is the angles that everything is at. In the diagram above, the front seat legs are angled back at 20 degrees, while the back legs angle forward at only 10 degrees. I realize the drawing doesn’t look that way, but that’s an optical illusion. The bottoms of the legs need to be cut off appropriately to match that angle or be fully rounded so that they will sit solidly on the floor. The seat is angled up slightly, at 5 degrees for comfort. Its front edge should be 17 to 19 feet off the floor for adult chairs.
The two hinge joints consist of bolts with nylon-insert lock nuts. Flat ashs should be used beneath both the bolt head and the nut. Most people don’t realize it, but flat washers have an “up” side and a “down” side, created in the manufacturing of the washer. When the washer is stamped out of sheet metal, the pressure against the stamping die causes the top inner and outer edge of the washer to be curved slightly, while the bottom edges are sharp. Placing the sharp bottom edge against the shoulder of the bolt can nick it, causing failure. That’s not likely to happen here, as the bolt doesn’t need to be tightened up that much. But putting that sharp edge against the wood will help keep people from scraping their skin against it accidentally.
In the cutaway drawing below, I’ve added in a rubber ash between the two pieces of wood. This is not a requirement, but it is something I like to do, when I have two pieces of wood having to move up against each other, such as in this case. Rubber washers are available in the plumbing department of the local home-improvement warehouse. The washer keeps the wood from rubbing and damaging the finish and being made of rubber, it provides some resistance to movement, without it being excessive. That helps to keep the chair in whatever position (open or closed) it is left. Just be sure to account for the thickness of the rubber when laying out the chair.
I’ve also included the sleeves, showing how they would be used. It is possible to buy nylon bearing sleeves of this type or nylon spacers of this type very inexpensively, making a good addition that improves the quality of the chair, without much additional effort or cost.
Cross Braces are necessary, located close to the bottom of the chair legs. Note in the side-view of the chair how they are both located on the outside of the legs. This is done so that they will not get in each other’s way, when the chair is folded.
Folding Chair with Guides for Front Legs
I mentioned earlier that the easiest way to make a folding chair is to provide a channel in the back legs for the front legs to slide through. This is nowhere near as complicated as it might sound. In reality, it’s just judicial placement of the cross braces so that they form the channel. To make this work, the angles of both sets of legs need to change, and the back legs need to be attached to the front corner of the seat structure.
As you can readily see from the diagram above, this design requires longer back legs. It also puts the bottom end of those legs farther back; but that’s not a trip issue, as the chair back is leaning back farther as well. The one way this will make a difference is that the overall depth of the chair is slightly bigger; so if space is limited, it might be a good idea to avoid this design.
The two cross braces that were placed on the front and back legs are both placed on the front legs in this case, forming a channel that the back legs ride in. Note that the upper guide is placed to the back and the lower one to the front. This is essential so that the chair will fold. If they are reversed, so that the upper cross brace is to the front of the chair leg, the chair can’t fold. It’s not shown in the drawing, but it would be a good idea to add a cross brace to the back leg as well. That will help prevent the legs from loosening up over time and eventually collapsing.
Adding Arms to a Wooden Folding Chair
Folding chairs with arms aren’t anywhere near as common as those without; but it is possible to add arms to pretty much any folding chair design. There are also folding chairs that are made with different designs, just to accommodate the arms. When making a folding wooden chair with arms, the width of the chair might have to be made a bit broader, to accommodate larger people.
Each arm consists of two pieces, the arm itself and a support. The back of the arm is attached to the same pieces that make the chair back and the support is attached to the sides of the seat. This adds three hinge points: the back of the arm, the point where the support attaches to the seat and the point where the arm and support join together. Depending on the dimensions of the chair, it may be necessary to use a metal angle bracket for the hinge point between the arm and its support.
The diagram above, while a bit rough, shows both of the chair designs we’ve used in this article, with arms added. Some adjustment of the position of the arms and their supports may be necessary, in order to make the chair fold. In the one on the right, it might be best to use the same hinge point for the arm support, as for the rear legs. That would eliminate one hinge point and only require that the bolts used for the hinge point be longer.
By and large, the arms of these folding chairs are made of wider material than the rest of the chair’s framework. This is to provide a more comfortable arm rest. When this is done, it is essential that the arm sit to the outside of the rest of the chair’s frame, to ensure that it will still close correctly and the arm won’t get in the way of the other parts, when closing. If it is wide enough, a drink holder can be cut into the front end of the arm.