• Singer (pre-1970s models) – Models like the Singer 15, 201, 66, and Featherweight 221 are especially popular for their full metal build and reliability. • White (pre-1950s models) – Heavy-duty machines often built into cabinets, known for their rugged cast-iron frames. https://www.quora.com/What-are-the-old-sewing-machines-that-do-not-have-any-plastic-parts-Because-todays-sewing-machines-have-gears-and-most-of-the-components-in-them-are-made-of-plastic-So-what-are-the-types-of-old-sewing-machines-that/answer/Coherent-Market-Insights-1?ch=10&oid=1477743866412228&share=343104d3&srid=uTm6RG&target_type=answer