That looks really cool. I'm more interested in the vacuum gauge though, (I watched the video linked.) The Perf-o-meter has a patent number, perhaps you could look that up for more information? I did some searching and found one listing that included the text on the meter: "Rare, vintage auto Perf O Meter. Circa 1952. This meter appears to have been used to measure brake efficiency. Made in U.S. zone of Austria for Autosphere Corp. N.Y. Patent pending U.S. copyright 1952. Measures 4-1/2" in diameter. Circumference is 15". I then searched for Autosphere and found an article on Hemmings about Karl Ludvigsen that includes: "Meanwhile, we set up another company, Autosphere, to wholesale less-exotic car accessories. When the economy turned down at the end of the 1960s, both companies started hurting." It looks like a passive device that does not connect to anything, just zero it out and go. Oh, it looks like there is a 63 page book for the Per-o-meter and it is available from Two libraries: Bowling Green State University in Ohio, and Benson Ford Research Center in Michigan. ok, I need to use my time more wisely while at work, time for lunch...
Last edited by walterhvogel; 01/17/2019 6:49 PM. Reason: added library
