Instructions
Examine the body of the machine to note the construction. Most vintage examples were made from cast iron set into a wooden base until other materials, such as aluminum, gained ground from the 1930s onwards.
Check the machine's case. This was usually made of bentwood -- recognizable by its curved top -- but some early examples have a solid-wood housing.
Inspect the decoration. Almost all vintage sewing machines were coated in black lacquer, known as japanning. On early machines, this is relieved with a little gilt decoration, growing more elaborate and colorful on models from the 1890s until, by the 20th century, a utilitarianism design reasserts itself and the machines become relatively plain once more.
Search for a maker's mark. While some manufactures such as Singer enjoyed longevity, others came and went over a shorter period. For instance, a sewing machine marked Wheeler and Wilson would have been produced no later than 1907, the year the company closed.