As always, let's start with a little vocabulary...

What do we mean by Post and Rung?

A Post and Rung chair, often referred to as a Ladderback, differs from a Windsor chair in the way the parts are joined together. In a Windsor chair, the most important structural parts are joined to the seat. The back posts and spindles are joined to the top, while the legs are joined to the bottom. In a Post and Rung chair, the seat is typically added after the chair is built. And though it can reenforce the joinery, it's not an integral part of the structure.

Post
The posts are the legs.

At the front of the chair, they may be cut off just above the seat. If you're building an arm chair, they may extend to meet the arm.

At the back of the chair, the posts may also be cut off above the seat, as in the case of a stool. Or they may extend upward to create the back of the chair.

Rung
The rungs are the parts that connect the legs to form the structure.

In a simple post and rung chair, they are the horizontal members that cross between the legs below the seat. They also form the frame that, whether it is applied or woven, supports the seat. They may be joined to the legs in any number of ways, though round or rectangular mortise and tenons are the most popular.

What are Rake and Splay?

Rake and Splay refer to the angles of the posts. In a Windsor chair, whether you are talking about the legs below or the posts and spindles above, rake and splay are always referenced from the seat. Any part that doesn't join the seat at a 90 degree angle is said to have Rake, Splay, or both.

In a Post and Rung chair, the definition can get a little more complicated because we are joining the parts in open space, without the seat as a reference. We could be referring to the angle where the posts meet the floor, or the angles where the rungs join the posts.

To keep things simple, I like to focus on the structure of the chair at or below the seat. Since we're focused on this section where the posts meets the floor, I'll refer to them from here on out as Legs.

If any pair of legs is anything other than parallel, they have either Rake or Splay.

What's the difference between Rake and Splay?

Rake
Rake can be observed from the sides of a chair. It refers to whether the legs lean forward or back.

A clever designer can give the appearance of Rake by changing the height of a leg or joining the posts and rungs at an angle other than 90 degrees. (You'll see an excellent example in this week's video.) This is where it's important to focus on the center lines of the legs. If they're parallel, there is no Rake. If they're farther apart at the bottom than the top (the most common configuration), then one, or both of the legs has Rake.

Splay
Splay is seen from the front or back of the chair. If the center line of the legs are NOT parallel, then the legs are splayed.

The most common geometry for a post and rung chair is either vertical legs with no splay or legs that splay outward from top to bottom.
 
In this week's 5 minute video, Jeff will give an excellent visual introduction to these terms and show you some great examples of each.

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