Notes on chair design and manufacturing
We manufacture many of the chairs that we offer.
We have a long history of involvement in chair-making and feel that, based on our experience of making and selling literally thousands of chairs over our over 35 years, that we have a few insights into what factors affect the sturdiness of a particular chair design.
The single-most important indicator of chair manufacturing quality is the presence of finger-joined corner blocks under the seat,
Why is this a good indicator?
Although we currently make our chairs in our Brooklyn workshop for a period of several years we were involved in producing our designs in a factory in the Italian province of Friuli, in the far northeast. This region specializes in chair production and in the region .
There is an agency in the region, CATAS s.p.a. whose work centers on testing furniture for quality, strength and durability. Testing and discussions with the staff at CATAS indicated the importance of this design feature that is one of the main factors that enables a chair to successfully complete 30000 iterations of the standard test for rocking a chair on its rear legs.
Laboratory testing of dining chairs indicates that finger-jointed corner blocks are necessary if a chair is to endure thousands of cycles of rocking on the rear legs. The other important design features necessary to achieve high testing results are mortise and tenon joinery at the seat rails and the presence of a lower stretcher connecting the front and rear legs. This stretcher should optimally be joined using mortise and tenon.
As the sort of joinery used to join the seat rails to the legs is internal and, thus, hidden from view, the existence (or absence) or finger-jointed corner blocks is the remaining good indicator. Their presence indicatesthat the manufacturer is aware of their importance and is adept at integrating this feature in their production.
Alas the absence of finger-jointed corner blocks indicates either inability to integrate this important feature or ignorance of the importance of the feature – or both.
Of course, there are other types of chairs that are not adaptable to finger-corner corner blocks and this is another issue. But if a chair has legs and seat rails and doesn’t have finger-jointed corner blocks – the chairs is not to be considered strong enough for commercial use.