For those wondering what this is a part for: the Curta is the ultimate mechanical calculator (<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Curta" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Curta</a>)<p>Apparently, someone is trying to 3D print one. I find that ambitious; the tolerances of the parts will have to be tiny, and operating it will exert fairly large forces to the parts.