Near the end of a 6 hour drive to a convention that included a hearse show (which I had organized) I noticed that the air conditioner of my 1996 Superior Buick Roadmaster hearse wasn't doing the job so I picked up supplies to recharge it once I arrived at my destination. After popping the hood, I checked a known problem area with the Roadmasters, a loose nut on the auxiliary battery terminal before recharging the AC. It was loose so I put a wrench on it and moved it less than an 1/8th of a turn before the stud snapped off!
ALL the electrical in the Roadmaster (except the starter) is powered from that stud so the hearse was DEAD. This was not something any part store would carry so I was stranded 6 hours from home. After I ran out of interesting works to say, I calmed down and assessed the situation. Discounting several options that wouldn't work, I borrowed a battery powered drill in the convention center and hitched a ride to Lowes, which was nearby.
I selected a few lengths of bolts two sizes smaller than the stud diameter and went off looking for a tap and drill bit. That's when I learned how truly lucky I was. I was told they hadn't had taps for over a year and JUST got them in!
Thankfully, I was able to drill out and tap the stud and use the bolt to reattach the battery cable. I'm glad it happened there and not enroute!