Mechanical Pencil: An illustrated celebration of the engineering around us

15 hours ago (mechanical-pencil.com)

I took a look at the pen, but it's missing an explanation of what gets the cam to rotate clockwise in the first place, such that it catches a tooth of the barrel.

Such a beautifully done site. I might be in love already . Many kudos.

I dropped in a suggestion to do one on an umbrella. There's a lot going on in these. One can study the differential geometry of surfaces. The mechanism design of opening and closing.

I find both the spring ones (push button) and the ones without spring quite fascinating. In fact the ones without a spring has implicit ones imposed by the bending of the spokes.

It would be interesting to have further links/resources/research.

Apparently, Japan reigns supreme in the manufacture of mechanical pencil components w/ brands such as Rotring and Skilcraft importing, or contracting to Japanese companies either for manufacture (my Rotring Quattro is labeled as Made in Japan), or parts sourcing (my Skilcraft B3 Aviator multi-pen was noted as including mechanical pencil components imported from Japan).

One of my favourite mechanical pencils is a "357" imported from Japan which uses a Rotring-like gravity mechanism to select a 0.3mm, 0.5mm, or 0.7mm lead.

Wasn't always so --- I can still remember playing w/ a Norma 4-colour mechanical pencil my father had (which sadly wasn't among his effects when he passed --- just ordered a replacement off eBay...) Unfortunately, the page on this at: http://www.roger-russell.com/ is off-line.

I've always enjoyed that the cam surface for that particular push-push mechanism design (click pen) is not that dissimilar from a Leibniz wheel. It's so tempting to add more steps.

https://en.wikipedia.org/wiki/Leibniz_wheel

I can't help myself and have to link some of my favorite youtube channels.

Engineerguy: https://youtube.com/@engineerguyvideo

Chris Staecker: https://youtube.com/@ChrisStaecker

Nice, embodies the quote;

"What one man can invent, another can discover" -- Sherlock Holmes in The Adventure of the Dancing Men.