Bariatric Pressure

When the nineteenth century German-Austrian cabinet maker Michael Thonet (pronounced Toe-net) turned his attention to making furniture using bentwood, he perhaps had no inkling his technique for producing strength through elegant design would not be surpassed by other manufacturers in the ensuing century and a half. Some have made chairs just as strong, and others have created furniture attractive in the eyes of many beholders, but none have combined the two features as well as Herr Thonet did with his café chairs and other pieces. The furniture making business he established with his four sons in the mid-nineteenth century is still in production today.

There are no government regulations requiring furniture manufacturers to list weight capacity on their products for one thing, and for another, when a manufacturer does voluntarily list a weight capacity, they often do not specify whether it is for a static or dynamic load. Almost universally, the listed capacity is for a static load. A static load limit does not account for the uneven distribution of weight as a person shifts about in a chair, or when the person gets in or out of the chair. The seat may be listed for 250 pounds, but what happens when a sitting 225 pound person braces himself or herself against one arm of the chair in order to stand up? Now the arm and one side of the chair are under an extraordinary strain they may not be built to withstand.

The beauty of furniture made by Thonet and other similar manufacturers lies not only in the graceful curves of their bentwood structure, but in the strength inherent in those curves of superior pieces of wood and in the simplicity and effectiveness of their joinery. It is difficult to imagine the manufacturers of highly padded living room recliners using the same pine sapwood for structure, and brads – brads, of all things! – for cheap, rapid joinery, if their handiwork were open for all to see the same as it is with a Thonet Number 14 café chair, a timeless design that continues to sell.

Thonet still makes the No. 14 chair, though now they call it the No. 214.

There have been other factors figuring into the enduring popularity of the No. 14, such as how its simplicity lent itself to mass production, lowering costs, and how the paucity of joints, which were strong yet simple, allowed buyers to assemble the chair themselves, saving space and freight costs since the Thonet company could ship the chairs flat, as a set of constituent parts. Perhaps the largest factor in the success of the No. 14, as well as similarly designed and constructed bentwood pieces of furniture, was that even in the days before independent bodies tested chairs for strength and durability, buyers knew these pieces were stronger than they appeared, a vital consideration for shop owners serving customers who could tip the scales anywhere from 40 to 400 pounds.
— Techly