A source of near-constant consternation for
epee fencers.
There are two teeny tiny screws in the barrel of the electric epee
blade that keep the tip of the blade from flying off into space.
Unlike in foil, there is nothing covering these screws. Being so
small (not microscopic, but close), they tend to loosen and fall out
fairly easily--just a few matches of constant jarring can sometimes do
it.
You really can't tell if one of the screws are missing unless you actually
look and check, so it's not entirely uncommon for an epeeist to suddenly
notice he's been fencing without a tip for the last three points.
My sophomore year of high school, the coach of my fencing team bought
the wrong size screws for our epees (we didn't find this out until almost
a year later). Due to this, the average time a screw would spend
in place was about one match. We'd tighten them, check it before
every match, tighten them some more, but it just didn't seem to matter.
One day towards the end of the season, determined to not have to buy
any more epee screws, we took a magnet and walked up and down the gym
trying to collect lost screws. We found over 200 stuck to the magnet
by the time we finished.