My latest project is to build a rocking chair. I have never built a rocking chair before, so before even starting to design the chair I had to do lots of investigation and have several discussions with the customer. Rocking chair design is quite different to chair design. You use a rocking chair to relax and perhaps have a snooze in. It needs to be really comfortable!
My investigations told me that the important measurements for a rocking chair are the rocker radius, the seat size and the height of the seat. These measurements are quite well understood and documented by various rocking chair makers. One of the most respected makers of rocking chairs has written an ebook and sells plans. His name is Hal Taylor. You can find out more information from his website http://www.rockingchairuniversity.com.
So I decided that I should not ignore many years of making rocking chairs and use Hal's measurements and some aspects of his design.
There were a few aspects of Hal's chairs which my customer did not like so I decided that, before I started making the real thing, I would make two models:
(1) a full scale model of the chair which would demonstrate the sizes and ensure that the customer is happy with the comfort of the chair;
(2) a quarter-scale model of the final chair, which I can use to discuss the aesthetics of the chair with the customer.
I now have the agreement of the customer to go ahead and start to build their chair!