I just bought this machine for $500 from a guy who didn't really know how to use it. When I picked it up he had 277 thread incorrectly threaded through the machine and was using a size 23 needle. The bobbin thread was very loosely wound and his top tension was extremely loose. He said the machine was always tangling up, the reverse never worked and he didn't have time to tinker around with it. He was using thick saddle and tack leather. He had bought it used from a seller who tried using it to s