The gears shot out as the face plates came flying off. Fancy looking, but entirely functional, brassy bits flying everywhere.
"Another failure," the Tinker sighed, "I really should just stop"
But the Tinker didn't like the idea of defeat. It was, in fact, loathed. So the plans were studied, the parts rebuilt, and the machine put back together.
"It should work this time... Then again, it was supposed to work all the other thirty-eight times as well... Grrrr..."
The truth of the matter is that the springs were overwound, which the Tinker found on the next rebuild. Thus fixed, the machine was promptly thrown out, as the Tinker had lost interest. However, there was a young street Urchin who found this broken piece of machinery, fixed it up, and brought it back to the Tinker, good as new.
The Tinker had found the one that would become the Tinker's apprentice. Thus instated, the Urchin found life rich and lived the Tinker's life for a while. However, the Urchin never forgot his life on the streets of the City, and eventually went back there, to the great sadness of the Tinker.
Thus, the Tinker never again saw the Urchin until the Tinker was about to die. Finding that the Urchin had started another shop and had wanted to ask the Tinker to see it. The Tinker was joyous that the Urchin, the hoped apprentice, had started a shop, nearly identical to the Tinker's. However, the Tinker died and was never shown the shop. Thus, the Urchin became the Tinker until the new Urchin was found.
And thus the it goes, Urchin to Tinker and back to the Urchin; the Tinker's cycle.