A more easier to make lens cap?

 

Already a few years ago I wrote a blog about making your own lens cap for your precious lenses.
http://collodion-art.blogspot.nl/2010/08/making-your-own-lenscap-isnt-that.html

Recently i visited a friend of mine, Henk Peters,  and he showed me his made lens cap

for his "new" Hermagis petzval.
This cap is even  easier to make.

 

But at the same time I realized I had a lens holding a similar cap.

It is one of my first large format lenses I ever bought, a Voigtlander Heliar Universal.

On that lens there still is it's original lens cap which works exactly the same way.