Wooden chair frames traditionally have a bent back leg. The legs need to splay out towards the floor to carry the load back and keep the chair from tipping, and they need to splay out upwards to ease the sitter back to a comfortable angle of repose. Round stock is often steam bent to achieve this, and square stock is band-sawn. Band-sawing requires a wide board in order to yield the curved or raked part, and produces quite a lot of waste material in the process, often exceeding the yield of the final part in volume.
In developing the Elder Chair, I invented a technique to make a bent back leg out of a single piece of square stock, dimensioned to the final part. Making a single cut to the stock at a carefully chosen angle (see the video clip above), then flipping and laminating the upper portion to the back of the lower portion yields a stronger leg while producing no waste, saving time and adding a compelling visual feature by reversing grain patterns.
The technique requires designing and building a ‘jig’ to position the piece and secure it in place for a safe pass over the table saw. It is best suited to small production runs and may not be suitable for one-offs due to the time invested in building a jig.
Rough stock is graded and milled to produce the most seamless effect while ensuring structural integrity. Even in a fairly automated process, the chair’s design is strongly informed by a knowledgeable maker.
I have designed a ‘Jig-Cam’ to illustrate this simple process, and will continue to incorporate a camera mount to my jigs in the future.