Engineers Explain How Click Pens Work

This was a bit surprising: A YouTube video in which an engineering professor explains how a retractable pen works became a bit of a viral hit.

The simple 4:43 video from Bill Hammack – “engineerguy” on YouTube – had been viewed more than 370K times when I last checked, about a month after it was posted.

In the video, Hammack uses a Parker Jotter and some 3D modeling graphics to describe the interplay between plunger, cam, and spring that extends and retracts the ink cartridge and produces that distinctive clicking noise.

Hammack is a professor in the chemical engineering department at the University of Illinois at Urbana-Champaign. He explained in an email to us why he used the Jotter for the video.

“We choose the Parker because it was iconic. It seems to be the
earliest that was retractable, at least the one of the earliest that was mass produced. It is familiar to many of our viewers.”

The video became such a hit that wire service Reuters sent out a brief news story, which is how I heard about it.

When I started poking around a little, I found a couple other intersections of pens and engineering that I thought were interesting.

• Engineers at Tufts University have put together an entire lesson plan for primary school teachers to teach their students basic engineering by disassembling an ink pen. The reasoning:  “Performing reverse engineering by analyzing the interactions between parts contributes to a better understanding of how something works.”
• In 2011, engineers from Seoul National University and Harvard University conducted a study of the hydrodynamics involved in putting ink on paper. Why? Because “understanding how to combine the dynamics of swelling and imbibition in soft porous media with the rate of deposition will allow us to create functional porous substrates by writing on ever smaller scales—perhaps even rejuvenating the ink-pen in a different guise?”

We know exactly how you feel, engineers. They fascinate us too.

Meanwhile, these guys aren’t engineers, but they do have a cool video showing a ballpoint pen laying down ink in extreme close-up.

It’s in a Scandinavian language, but thankfully there are subtitles. Also some cool music. This one has been viewed nearly 650K times since it was posted in February.

Nice to see pens getting the glamour treatment.