I really love to hear about the history of some of the tools we use daily and take for granted. A toolmaker I worked with years ago told me about how the first lathe "leadscrew" came about. What came first the chicken or the egg? sort of thing. I had never thought about it until he told me. He said it was a hand chiseled round bar that was put into a machine to cut a better one. The better one was then used to cut a better one and so on until a smooth screw of a certain pitch was the result. If this is true the first one (which he said is in a museum) would be the "Holy Grail" of engineering to me. I don't know how close I am to the real story, but it sounds true. I love that sort of thing ... Nice education watching your videos Don, I wouldn't miss one..... Peter Spence.
There's at least one book that goes into this in detail. It's a lot weirder than that, at the end there were a bunch of screws that were pretty close and used several at once to drive the lathe carriage, and then there was measurement of the error which was used to make a compensator that could change the pitch locally to make it more perfect. It's quite a story! I think it IS something that mechanically-minded people should know: How precision came out of nothing, how people started with stone tools and ended up with (say) gage blocks! Much of it happened in historical times, right? These are the legends of my people.
C E Johansson invented a lot of smart stuff,among others the adjustable wrench. The first gageblocks were metric,and after a minute of head calculating he knew instantly he needed 102 blocks.I wonder who and how they were "translated" into inches? Love your videos about this and that.
+Kjell Carlsson That's a different Johansson. :) J.P. Johansson (which became involved with Bahco). The conversion was easy in theory, as both systems used decimals. The big problem though, was that the inch wasn't a fixed measure! The U.K. and U.S. had ever so slightly different inches for instance, up until 1959. The U.S. inch between 1893-1959: 25.400051mm The U.K. inch pre-1959: 25.399917mm In 1959 they split the difference so to speak, so an inch is defined as 25.4mm exactly. Although in the industries they had already done that in the '30s.
@@MPI1000 My understanding is that Johansson talked the US government into this definition, and also was the one that came up with 20C as the international standard temp for measuring. Here that seems pretty chilly, but supposedly some Swedish metrologist remarked on how much fuel they had to burn to make it so warm in their lab!
+Thomas Wallblom CEJ does not exist as a company anymore as of last year in C.E. Johansson's (also my) home town of Eskilstuna. They used to make micrometers, calipers, microcators, et.c. all through the 1900's. In the 90's to 2000's their thing was 3D measuring stations. But it folded completely. :-/ The brand name is sold to some other company.
I know I'm not the sharpest hammer in the box, but I didn't understand anything after Margarita. And BTW, was she good looking? Do you have any slides?
1.0" = 1 inch 0.100" = one hundred thousandths of an inch 0.010" = ten thousandths of an inch 0.001" = one thousandths of an inch 0.0001" = one ten thousandths of an inch (tenths, this is the measurement Don is referring to) Thank you for watching.
I swear to all the tool gods DON you should open a machinists school there at suburban and reteach all the youngsters what is what...NONE of this is being taught in machine theory at all NONE.
