It may be possible for Sam to pass on his method in one-on-one teaching but you can’t really disseminate knowledge widely without some degree of codification in numbers. It’s easy to say the chair feels comfortable to you but this glosses over how the chair was built in the first place. Is it based on an adjustable prototype or knowledge gained from years of trial and error?

On the other hand a chair is too complex to be reduced to a small set of numbers or a ‘formula’. Chairs vary so widely in their structure and purpose. A seat angle that works well for a comfortable reading chair will be quite inappropriate for a formal dining chair. If you take the example of a continuous arm chair (such as George’s Ming Chair) the ‘correct’ height of the arm will depend on factors like the angle of tilt of the arm (and for some chairs this may vary along the arm) and the distance of the arm from the sitter, ie the width between the arms. Do the forearms rest horizontally or are the wrists well below the elbows or somewhere in between?

My approach is usually to start with some guidelines such as the height and width of the seat, height of the lumber support, etc. These might usefully be expressed as a range. And then I adjust these variables for the specific design. And then I prototype, test and refine.

Unless we happen to know that the chair will be used only by a particular person, we always have to design for the average but allow for variation in form. Being of average size is certainly an advantage because you can test your chairs yourself.

Thanks for sharing your tale, Bill (and for the name-dropping!)

Sam said he laughed and told them his ’secret’. He made chairs that were comfortable for himself - he figured he was of average size and if he was comfortable then other would also feel that way. He said he had no formula but they were free to measure angles and take measurements.

He really chuckled at this story.