I did buy a Singer Merritt one time. It was cheap plastic and stamped metal. The lady said she took to a shop to be serviced. The shop guy told her it had a broken gear. When I opened it up, the gears were fine. Under the machine was a loose bobbin. The belt was wrapped with that bobbin's thread - so tight the machine wouldn't move. I untangled the mess and the set the machine free. You never know what is wrong with a machine until you actually look.