a very basic peg to keep 2 weight plates together while doing plate pushing exercises.  fits the standard 2" olympic weight plates snugly.  I printed with ABS, but it probably could be done with PLA.  you'll want to print it on its side, with the flat part of the cap facing the build plate.  I did that so its oriented in a way that's strongest in use.  it is a bit more painful to print that way, and yeah you'll need supports, but its really strong.  I printed with 60% infil, but you could probably get away with 25-30% if using abs/asa.  I also did 7 perimeters/top/bottom, just because it'll take a beating over years.