This collection of exploded diagrams lays out the late 1970s Simplex range in exquisite detail - but I still cannot begin to understand it.
First there is the strange ordering of models. You might think that higher numbers point to a superior product. But in the SX series, the SX810 has a plastic front knuckle, whereas the SX410 has both knuckles manufactured in aluminium. Is a plastic front knuckle superior to an aluminium one? If so, how do you account for the fact that in the SLJ series the models with the highest numbers are those with two aluminium knuckles?
Then there is the incomprehensible duplication. What is the difference between the SX100 and the SX110, between the LJ1000 and the LJ4000 or between the SLJ5001 and the SLJ5500? I never knew then and, even after examining this learned tract, I don’t know now.