The back legs of our chairs flare out at an angle of two degrees. This contributes to a look that I see as supple and flexible. There are many stiff and brittle looking chairs out there. To flare out at two degrees, the notch that fits the seat must be cut at two degrees. We have built a jig to guide the router when cutting these notches. We use a vacuum to hold the legs while machining. Note the vacuum lines from the pump and the pitch of the legs in this photo of Will working.
The notches produced by this simple router jig are accurate.
We temporarily plug the notches so we can shape the legs without worrying about their notch.
After sanding, we knock the plugs out, leaving the edges of the notches and the contours of the legs clean, crisp, and true.