The Plastic Oil Container Cap Opener is a tool I designed to address the challenge of opening the caps on large plastic motor oil containers like this one:

As it turns out, they are quite stubborn and almost impossible to open by hand. After using a pipe wrench to open the caps, it damages the plastic lamellas and makes the cap manipulation even more difficult. This led me to create this 5-minute design for a cap opener. It fits caps with 67mm diameter, with 8 lamellas, each with a maximum width of 4.5mm, and has already been tested for over a month in quite a busy car shop, withstanding many caps without any visible damage.

I used PLA+ with 25% Gyroid infill at 0.2mm layer height and 6 wall loops. The top and bottom layers are unimportant, but I printed it with 4.