Well, this time, i said to myself, i'll fix it once and for all — and i marched off confidently to the hardware store. All i needed was something to put on the end of the belt rod that would keep the belt from slipping off. After talking to a Clueless Woman who didn't understand what i was looking for and thought they didn't have it, i found the part myself: a $2 metal ring with a set screw that would hold it in place around the belt rod.
But the set screw had a hex head, so i went looking for hex keys. The proper-size hex key was 50 cents. But there! Right next to it! Was a package of three folding thingies — one with a complete set of Imperial-sized hex keys, one with a complete set of metric hex keys, and one with a complete set of star-shaped hex keys. Gasp! At last i could be free of the tyranny of not being able to take apart Apple hardware.
Fig. 1. My previous relationship with hex screws.
I could not resist. I confessed my weakness to wealhtheow on the phone, then succumbed and bought the set. I went home a newly empowered human being.
Fig. 2. My new relationship with hex screws.
And that's how i went to the hardware store to buy a $2 part and ended up spending $30.
(P.S. The vacuum cleaner is fixed and works like a charm.)