Originally Posted by
Kindascrappy
I have a 603 T&S I bought from Goodwill on impulse. I think it is the same machine design. It takes a plastic bobbin which you can empty by simply twisting apart. The 603 has steel gears but I think the 700’s have nylon. If you decide to clean it up careful with the oil around that nylon. Bet you can download a free copy of the owners manual off the internet. Good luck
Yes, the 603 and 600 are the metal beveled gear drive design and a much better design I feel from what I've observed, though have only been working on sewing machines for little over a year. The 700 series uses a timing belt to drive the lower end of the machine, where-as the 600 series from what I've seen uses a drive shaft with bevel gears on each end of a vertical shaft instead of a timing belt and on the upper and lower horizontal drive shafts a bevel gear instead of a timing belt pulley.
I do wonder what all can be done to have options to retro-fit the 700 series with either the bevel gear design or maybe even a better quality timing belt material or timing belt pulley and timing belt.