[paulsherwin]

The domestic machines made from the 1890s to the mid 1960s are very similar apart from the actual lockstitch mechanism (boat shuttle or rotating hook). They use very robust Victorian engineering practices and have almost indefinite lives if maintained properly. I still have the Jones Family CS bought by my maternal great grandmother on HP in 1897, and it still sews quite well despite having seen very heavy use (it was used for commercial outworking for several decades).

When the mechanisms have seized after long periods of disuse this is usually the result of dried up lubrication. You were supposed to oil them with sperm oil at least annually, but this was expensive so people would try all sorts of things, particularly bicycle oil made from castor oil. The official advice to free them up was to soak everything in paraffin, but nowadays lots of WD40 works well. They obviously need to be lubricated properly with machine oil afterwards.