One cam operated the forked needle (fig. 5) that pushed the thread through a hole made by a preceding thrust of the awl. The thread was caught by a looper and detained so that it then became enchained in the next loop of thread. The patent described thread tighteners above and below the work and an adjustment to vary the stitches for different kinds of material. Other than the British patent records, no contemporary reference to Saint’s machine has ever been found. The stitching-machine contents of this patent was happened on by accident in 1873.[5] Using the patent description, a Newton Wilson of London attempted to build a model of Saint’s machine in 1874.[6] Wilson found, however, that it was necessary to modify the construction before the machine would stitch at all.
Figure 3.—Tambour needle and frame, showing the method of forming the chainstitch, from the Diderot Encyclopedia of 1763, vol. II, Plates Brodeur, plate II. (Smithsonian photo 43995-C.)
This raised the question whether Saint had built even one machine. Nevertheless, the germ of an idea was there, and had the inventor followed through the sewing machine might have been classed an 18th-century rather than a 19th-century contribution.
Figure 4.—Weisenthal’s two-pointed needle, 1755.
Figure 5.—Saint’s sewing machine, 1790. (Smithsonian photo 42490-A.)