My recollection is that when I was studying Engineering back in the Sixties, the Imperial units-of-measure for torque were "foot-pounds" and "inch-pounds". But now when I watch automotive TV shows or look at the specifications for engines on the car manufacturer websites, the unit-of-measure for torque is "pound-feet".
I thought maybe my memory was faulty, so I dug out my old Strength Of Materials text. Here's problem 2-10 at the end of the second chapter on the subject of "Torsional Loading".
2-10 Determine the minimum diameter for a solid circular steel shaft required to resist a torque of 12,000 ft-lbs without exceeding a shearing stress of 6000psi.
When, why and by whom was it decided that the unit-of-measure for torque needed to be changed from foot-pounds to pound-feet.
Edited by - RB3 on 08/13/2024 07:03:13
quote:
Originally posted by RB3
When, why and by whom was it decided that the unit-of-measure for torque needed to be changed from foot-pounds to pound-feet.
I am anything but an engineer. In fact, I am so mechanically disinclined that I have trouble screwing the top back on a jar of mustard without crossing the threads.
That being said, it should be obvious that the change was made after a long period of discussion and debate. Because after all, torque is cheap.
I'll show myself out.
Back away from the imperial. Embrace the metric.
Wayne ... I've noticed that one too. I expect the switcheroo was made by "experts" and I've been told m-a-n-y times that I should always defer to the pronouncements of experts. And if all else fails we can rely on, "new and improved." 
And Skip, I have a slick [sick?] solution to the cross-threaded mustard jars:
... or better still some of these, so you can ease yourself through a transition/adjustment phase. 
... so long as you're careful not to apply too many pound-feet of torque. 
I think you are getting the torque necessary to tighten a nut mixed up with the torque an engine can produce.
Same word but different applications.
The metric version is Newton-meters, so it makes sense for the imperial to be called pound-feet or pound-inch. I have seen both foot-pound and pound-feet used, but never meter-Newtons?
quote:
Originally posted by BuddurI think you are getting the torque necessary to tighten a nut mixed up with the torque an engine can produce.
Same word but different applications.
That is the same torque. Torque is a measure of rotational force. There isn’t 2 applications.
I am not sure what the units of measure are on my ancient torque wrench. I just pulled on it until recommended numerical value reached. Brad
quote:
Originally posted by RB3My recollection is that when I was studying Engineering back in the Sixties, the Imperial units-of-measure for torque were "foot-pounds" and "inch-pounds". But now when I watch automotive TV shows or look at the specifications for engines on the car manufacturer websites, the unit-of-measure for torque is "pound-feet".
I thought maybe my memory was faulty, so I dug out my old Strength Of Materials text. Here's problem 2-10 at the end of the second chapter on the subject of "Torsional Loading".
2-10 Determine the minimum diameter for a solid circular steel shaft required to resist a torque of 12,000 ft-lbs without exceeding a shearing stress of 6000psi.
When, why and by whom was it decided that the unit-of-measure for torque needed to be changed from foot-pounds to pound-feet.
Wayne ..... you may be only the second person I have ever encountered that took "Strength of Materials". I took it, and by some miracle, passed ..... probably by the skin of my teeth. Statics and Strength of Materials were not courses any other architecture school required except at my alma mater and as a general rule engineering professors hated architecture students because we saw things in other than black and white. My professor, Dr. McCormick wrote the book that we used and unlike other engineering professors, I think he only mildly hated us! Certainly it is very unengineer like to change wording that has been with us for years. The name change probably has something to do with progressive liberals taking over the universities, which of course architecture students were even when I was in school.
if they are using pi to figure this out--it will be an endless struggle along the lines of--playing an open G against all chords
We have to get our torque wrenches calibrated every year. This year our wrenches were out for calibration and a time sensitive job came in requiring safety cable hardware to be torqued and striped with torque seal. We decided to buy new wrenches. The old wrenches were imperial but the new wrenches were metric (meter/Newtons). Our engineering specs called for 300 inch/pounds. We had to find a conversion to metric. 1 inchLbf = 0.112985 mN. So we needed about 34 MN to equally 300 inchLBs.
Edited by - MoPac fan on 08/13/2024 10:32:22
My of 18th edition of Machinists Handbook lists torque as foot/lbs & inch/lbs. Not until the 19th edition did the US even consider adapting metric anything! Although it matters not, as the formula being constant knows not the difference between ft/lb or lb/ft
Edited by - monstertone on 08/13/2024 11:31:05
I'm pretty sure his mind wasn't on either foot-pounds or pound-feet but back in the day, when one of my cruising/carousing buddies figured it was time to do something besides stand around shooting the breeze, he'd typically announce either: "Okay, let's giv 'er torque." or "Okay, time to give 'er torque."
Edited by - Owen on 08/13/2024 12:02:46
I really do not know fer sure..
But..i seem to recall a time when the way to measuer engine tourque..
Was done at the crank..n.now it may be done at the wheel..
You might need to ask A..Real..Gear Head..
That may know.
Much as I appreciate the simplicity of the base ten metric system, I am unable to think of measuring ANYTHING in terms of NEWTONS, because of THESE!
Fwiw, I like those ^^ things, Mike. I tell my wife that they're just a good preparatory step to when I'm in a care home and Voortman gets served up.
Before I matriculated to engineering school, I thought Newton Meter was the guy in charge of the FCC, who once argued that television programming was a "vast wasteland".
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