A friend just called - went out camping, long way innawoods, said the gearshifter on his car just moves freely and doesn't shift - a manual car so prob the gear linkage has come loose. An easily repairable issue, but to get to the gear linkage, he'd have to remove the airbox and battery and those require a 13mm socket.

Trouble is, he doesn't have any tools with him. Do I really have to drive out a few hundred km to rescue him or does anyone here know of good ways to diy a contraption to turn bolts and nuts with?