I wouldn't have thought that the Allied forces could have been stalled by a lack of wrenches and hammers—just as I wouldn't have expected that American soldiers in Iraq would have to make their own Humvee armor. But in both America and Britain, during WWII, basic hand tool shortages regularly slowed down troops. Luke sent along a excerpt from Walter J. Boyne's Boeing B-52: A Documentary History, explaining the impact of this shortage on American troops:
There were curious anomalies in the system as it grew. When hand tools were in such short supply, crew chiefs shared them, one set between each two B-47s. It was crazy to have two $3,000,000 aircraft sitting side by side with a $400 tool kit between them, and two master sergeants arguing over whose turn it was to use a ratchet wrench, but that's the way it was. Tools came out of one pocket, and aircraft out of another.
Similar problems occurred for British troops, as Robin Higham explains in an Air Force Journal of Logistics article:
At the squadron [fitters & riggers] reported to A, B, or C Flight where they were issued a toolkit. If they were transferred from one flight to another, they had to turn in their toolbox and have the contents accounted for before proceeding across the street to draw another set from their new flight. In biplane days, a fitter or a rigger assigned to a two seater not only acted as the gunner, but in colonial theaters lashed his toolbox to the wing next to the fuselage in case of a forced landing. [...] What this meant was that in a theater then desperate for serviceable aircraft, many were standing idle because the necessary repairs could not be made for want of a spanner, let alone the necessary spares.
Even an impeccably trained Air Force mechanic can't do a thing without the right tools. All the more reason to use standard, simple fasteners as often as possible—the fewer barriers to repair, the more likely that someone will be able to make a fix when it really matters.