A tinker comes to solder among the ladies with "his soldering-iron tool." An old woman asks that he solder her bones. "A country chap" takes the tinker's daughter but she is rescued. If a woman had been honest, she'd have "a baby belonging to me"
I won't pretend to understand how "the tinker he was nasty and was looking for a swap When up steps a country chap took his daughter in a truck" ties into the rest of this. On the other hand the sexual coding seems clear in the chorus "with his rosin box and itchy pole, his hammer, knife and spoon, And his nipper-tipper handstick and his soldering iron tool." - BS