Next Monday I start teaching another sack back class. Once the students have settled in, get a cup of coffee, and are seated on their stools, I will begin with a 20 minute introduction to Windsor chairs as a revolutionary piece of furniture. If you have taken sack back, this posting will be very familiar. However, even if you have heard it before, it doesn’t hurt us to pause once in a while and consider again the basics of our craft.
To better understand why Windsors were so revolutionary, let’s first talk about the other way of making chairs. It is certainly the older way. The first recorded use of this method is the ancient Greek Klysmos chair, a form that was developed by the 5th century B.C. Women depicted on Grecian urns and Attic vases are often shown sitting in this type of chair. The method of construction used to make a Klysmos had probably been around a long time before ancient Greece. For us, the important point is that while Windsor construction has been around for centuries, the other has been used for millennia.
In the other, older method of chair construction the rear legs are also part of the back, as the rear legs continue up to create the stiles. Thus, the chair’s back and undercarriage are a single unit. Ladder backs and all the formal style chairs — Chippendale, Queen Anne, etc. — used this method. So did those awful Shaker chairs made by those vile and treacherous Shaker chairmakers from Shakermaker U.
The chair back is framed by those two stiles. They create two strong vertical lines, around which the chair has to be designed. There are no alternatives. Make a chair this way and you have to deal with those stiles.
The stiles have to be held together by a horizontal element that keeps them from separating. In a cabinetmaker chair, a shaped crest rail is secured to the stiles with mortise and tenon joints. On a ladder back type chair the top slat is generally pinned to prevent the stiles from separating.
In this earlier method of chair construction, there is a void, a space between the stiles. This void is filled with some element that conforms to the sitter’s back. Cabinetmakers generally used a vertical splat, which is curved to the shape of the human spine. In a ladder back, the space between the stiles is filled with concave slats.
In this first method of chair construction the seat is an open, four-sided frame. Like the back, this void, too has to be filled with something comfortable. Cabinetmaker chairs are usually upholstered. An upholstered seat is essentially a cushion that conforms to the shape of the sitter’s backside. A ladder back chair seat is usually woven from a material called rush. Traditional rush was the long leaf of the cattail, a water plant that grows abundantly in marshes. The leaves are twisted into a rope and woven to create a concave seat. Hickory splint was used for chair seating, as was cane. The Shakers used woven cloth tape.
This older method of chair construction has a major problem. The four-sided seat frame is joined to the legs, and each of these joints is a weak spot. If the legs separate, the chair will break at one of those places. Rotational forces created by a shifting, squirming human being will tear at those joints, eventually wearing them out.
Over the centuries, cabinetmakers and chairmakers using this method of chair construction have usually added a stretcher system to their chairs to protect these weak points. These stretcher systems — H, box, or other — all served the same critical purpose. They hold the legs together and keep them from separating. If they do separate the chair will break at one of those four weak points, as surely as the sun rises in the morning.
This first method of construction also suffers from other constraints that limit comfort. First, the seat has to be parallel to the floor. Second, the amount of cant to the back is limited by the grain in the leg/stile. The more the back cants, the more the stile is cut across the grain and the weaker the chair. So, this type of chair holds the sitter’s thighs parallel to the floor with his back bolt upright. While your mother would be proud of your posture, you are not comfortable.
Shaker chairmakers tried to find a way around the problem of an upright back by canting the entire leg/stile. While this solution created some recline to the back, it moved the pivot point (the ends of the rear legs on which the chair tips) under the sitter’s center of gravity. You don’t have to be a Windsor chairmaker to know how dumb that is.
Now that you understand the first method, let’s contrast it with Windsor construction. The Windsor chair’s solid wooden seat is the truly revolutionary development. There are so many diverse styles of Windsor chairs, that what we call Windsor is really a method of construction developed around a solid wooden seat.
The identity of the guy who came up with this idea is lost to History. We only know he was working in England sometime around the turn of the 17th to the 18th century — about 1700. We can be pretty sure he was a trained chairmaker.
The solid wooden seat was revolutionary because it divided a chair into two separate systems: the under carriage and the back. The solid seat not only served to support the sitter, it provided a strong, reliable anchor for the two systems. Unlike the other method of construction, neither of these systems is weak, and they do not require protection.
Dividing the chair into two systems made possible a host of new possibilities in design. First, chairmakers were no longer forced to design around those two strong vertical lines created by leg/stiles. They were free to design chairs in ways that had not been heretofore possible. They could use bent bows, or crests perched on top of long spindles. Of course, stiles remained an option for a Windsor chairmaker. They occur in fan back arm and side chairs, and all the 19th century Sheraton period Windsors.
The solid seat also created a revolution in chair construction and joinery. In the older method the chair is weak where the legs are connected to a seat frame. Windsors are strongest at this point. Hardwood legs are secured with locking tapers into a softwood seat nearly 2 inches thick. (Everyone who has seen me lift a 300 pound bench top by pulling up on a chair leg pushed into a tapered hole, knows how strong this joint is.)
The older method of construction relied on rigid parts to resist the sitter’s weight and the stresses created by the sitter’s movement. Those stresses eventually tear apart the joints. A Windsor chair back is flexible. It is a web of flexible parts woven into a unit. My analogy is a suspension bridge. A suspension bridge too, is strong because it is a tough web of flexible parts.
A suspension bridge has to be anchored on the ends with concrete piers. So does a Windsor chair back. The back is anchored to the solid wooden seat by the stumps and short spindles.
New joints were developed to take advantage of the solid wooden seat. The faceted drive-fit tenon on the ends of the flexible long spindles is perhaps the most permanent joint in woodworking. The locking taper mentioned above locks the legs into the seat, creating a powerful, reliable joint.
While the locking taper is not permanent, it is renewable. This concept of joint as that retightens itself was and remains, revolutionary in woodworking. The same applies to joints in compression; parts that push others apart, rather than holding them together. They are a Windsor chairmaking technique and have no counterpart in furniture construction.
Windsor construction made possible a revolution in chair comfort. Because the leg/seat joints are so strong, the seat does not have to be parallel to the floor. It can be canted so it is higher in the front than in the back. This is a much more comfortable placement.
Because the back does not depend on stiles cut out of wood, there is no concern for creating weakness by cutting across grain. This means that Windsor chair backs can be canted more to allow the sitter to recline in a more comfortable position. The stumps and the drive fit tenons are so strong, a Windsor chair back is more than capable of supporting the weight of a reclining torso.
Besides serving as an anchor, the solid wood seat is thick enough to be deeply saddled. Its carved concave upper surface is body conforming, also adding to the sitter’s comfort.
All these improvements in chairmaking, made possible by the solid wooden seat, created the revolution in seating that we call Windsor chairs.
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