There are a few true mechanical machines that can be bought, Singer does one and so do Bernina, both reasonably expensive but most of the rest are very ho hum in performance terms. Made of plastic, poor head access, slow stitch rate and after a few years, no spares. Like many of the folks here my sewing machines were made in the late 60s, early 70s and are all metal. I own a few modern overlockers and the Bernina one is the best of the lot but I think if you are serious these days and want new equipment, you bypass the domestic modern stuff and go straight to proper industrials.