[u407]’s 3D printed Signspinner was created as a clean/dirty indicator for a dishwasher, and at its heart is a mechanism that works a lot like that of a retractable ballpoint pen. Every click of the ...

[Bill Hammack], aka the [EngineerGuy] is at it again, this time explaining how retractable ballpoint pens work. In this excellent video, he describes the simple (but remarkably sophisticated) ...

There are several popular types of pens, but when it comes to the best pens for note-taking, your best bets are ballpoint, rollerball, or gel pens that distribute ink evenly and don't easily bleed ...