I am looking for a short story. The story's main character ran a repair depot for spaceships in the neighborhood of earth. He was trying to expand into repairing those of the more-advanced alien species who visited earth. The problem - and maybe the title - was "the tools to make the tools". He finally gets the tech he needs by mind-scanning a visiting alien diplomat, who also turns out to be the inventor of the required technology. His success lets earth get "promoted" to a more senior membership in the alliance, or federation or whatever. Any help will be greatly appreciated.