Why I wanted info about strain gauges

All, I have been designing a new type of tapping head aimed at small shops with older equipment. It is designed to keep taps from breaking, it
detects missing, short or undersize holes, and it does windows. Well, it doesn't really do windows. Anyway, I thought that as long as I was making something that did all that it would be neat if it could report on dull taps too. I may be able to use clutch pressure to arrive at some torque number but I don't know how the clutch material behaves over time, if the pressure will change significantly over time for the same torque. The tapping head will easily handle #2 to 1/4 inch taps in soft and hard materials. I think it will even handle taps as small as #0. Experiments show that I am able to use it to tap #0-80 holes in steel without breaking taps but I am not yet convinced that a machine tool will be able to. When I'm tapping there is some feel whereas a CNC machine will only feed the tap at the programmed speed. I was hoping that some sort of strain gauge applied to some sort of rotating shaft subjected to some amount of torque might be pretty straightforward and cheap. It is not. But thanks for the replies anyway, I really appreciate it. Cheers, Eric
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snipped-for-privacy@whidbey.com fired this volley in

Torque transducers in all sorts of ranges and physical sizes are available.
You have conflicting specifications. If you want a torque transducer _cheaply_, you make it yourself as part of a mass-production scheme. If you want "straightforward", you purchase one or a few hundreds -- and that ain't cheap. You could probably do this design for five or six dollars in parts, if you made a million of them, AND had the capital to defray the research and design costs. If you make ten thousand, figure sixty bucks to do the same job.
The electronics and wireless (I'll say wifi or bluetooth, since those are so inexpensive to implement) are a tiny fraction of your cost.
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On Thu, 11 Dec 2014 17:04:20 -0800, snipped-for-privacy@whidbey.com wrote:

Good! Please limit it to Linux.
--
H.L. Mencken wrote in the American Mercury, April 1924, that the aim
of public education is not to fill the young of the species with
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On Thu, 11 Dec 2014 19:45:10 -0800, Larry Jaques

Mencken had it right. Back then, that's exactly what they *did* aim for. And it continued through most of the 1960s. They're still struggling to escape it.
"It wasn't until 1918 that nationwide compulsory education was in place.
"Part of the rationale used to sell this major transformation to industrialists was the idea that educated kids would actually become more compliant and productive workers. Our current system of teaching kids to sit in straight rows and obey instructions isn't a coincidence--it was an investment in our economic future. The plan: trade short-term child-labor wages for longer-term productivity by giving kids a head start in doing what they're told."
That's Seth Godin, in one of his TED talks. But you could read a good history of how education was shaped by the Industrial Revolution and you'd see the same thing. Educator-leaders at that time *overtly* explained that the new compulsory education was designed to produce obedient, compliant workers for the industrial age.
The problem is not how kids are being taught today, Larry. The problem is how YOU were taught. Now you resent it (rightly) but you carry with you the seeds that were planted in you then, using that to judge what education is struggling to become now, and through that lens you see the opposite of what is there -- because you haven't escaped the way you were taught.
It's not an easy thing to do. You can recognize it, though, when you hear someone who was schooled in the compliant age grumbling about "education today."
--
Ed Huntress



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On Friday, December 12, 2014 1:30:49 AM UTC-5, Ed Huntress wrote:

How did each states' high school valedictorian manage to disobey and get away from those conspiracies then?
(I guess there is always one kid in each state each year that rises above all that)
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On Fri, 12 Dec 2014 06:46:13 -0800 (PST), snipped-for-privacy@hotmail.com wrote:

By being exceptional people who recognized it and rejected it. That's how most who escaped did so.

There are many more than that. But, for the most part, it's been very effective at turning out compliant people.
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Ed Huntress

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Ed Huntress wrote:

Ed , do you know anyone that is in education ? The current crop of teachers is heavily invessted in making the kids into compliant little sheeples that will do whatever they're told by any "authority figure" . They don't want these kids able to think for themselves , just do what you're told . My wife was guilty of making the kids she taught want to learn and grow and think for themselves , and it got her fired . Last straw was when she was attempting to gain national certification , her then-principle did everything he could to block that . And then created a situation that he used to fire her . -- Snag
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wrote:

My wife and most of her friends.

That's the opposite of the case here. Teachers are rebelling against all of the conformist program. Here in NJ, there is an uproar over "Common Core" and the rest of the compliance nonsense. There is a lot of teacher/administrator tension and there are a lot of discouraged teachers.

Too many school administrators are pricks.

--
Ed Huntress

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On Thu, 11 Dec 2014 17:04:20 -0800, snipped-for-privacy@whidbey.com wrote:

How are you going to tell (each and every time) the "smart tapping head" which material, what treatment/coating, what thickness, what size, what thread class, roll-formed or cut, etc, Eric?
http://tapmatic.com/images/pdf/Tapping%20Questions%20HB.pdf
And as Lloyd asked, "cheap"? <g>
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of public education is not to fill the young of the species with
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