Planimeter - photo

[Jon]

Planimeter.

Fullsize image: https://diqn32j8nouaz.cloudfront.net...r_fullsize.jpg




More: https://en.wikipedia.org/wiki/Planimeter

Previously:

Custom bowling ball hand measurement tools - photo
Wet film thickness measuring tool - GIF
Spherical densiometer for measuring forest density - photo
O-ring measuring calipers - photo
Tool for measuring the flat on the end of a single point threading tool - video
Craniometer for measuring human skulls - photo
Tour de France sock height measuring tool - photo

[mklotz]

Or you can just use your pocket knife...

https://spaco.org/Blacksmithing/FinnishPlanimeter.htm

as a form of Prytz planimeter...

https://www.jstor.org/stable/2971268...o_tab_contents

[Toolmaker51]

Or you can just use your pocket knife...

https://spaco.org/Blacksmithing/FinnishPlanimeter.htm

as a form of Prytz planimeter...

https://www.jstor.org/stable/2971268...o_tab_contents

Nope;

While I appreciate the Prytz, this one was a small priyce, cased and elegant. Reminded by idea from PJ's in ways to scale things, especially pictures. Always had a thing for K&E anyway, had this since '77. Just need to know size of something on the same sheet. Another winning scaling instrument is proportional divider
The pocket knife is creative, but looks tedious for curved shapes.

[mklotz]

While I appreciate the Prytz, this one was a small priyce, cased and elegant. Reminded by idea from PJ's in ways to scale things, especially pictures. Always had a thing for K&E anyway, had this since '77. Just need to know size of something on the same sheet. Another winning scaling instrument is proportional divider
The pocket knife is creative, but looks tedious for curved shapes.

It is tedious. I've tried it and can say that with assurance but, surprisingly, it's fairly accurate.

Still, if you want to impress folks, the visual complexity of the commercial units is perfect. Amazed by their appearance, observers are even more impressed when you tell them you're measuring AREA. (Well, the dumbeddownees who know what area is will be impressed.)

Want to really stun them? Start scratching the integrals for Green's theorem in the dirt by their feet while muttering, "this will be obvious to the most casual observer".

https://en.wikipedia.org/wiki/Green%27s_theorem

[NortonDommi]

I think it was Popular Mechanics that published plans for a simple one in the late 1960s. I remember being fascinated as to how they work.