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So I got a torque wrench a few months ago and noticed that the units are "Foot-Pounds" and the service manual I have gives the units in "lbf-ft", so pounds-foot I assume. I see there is a difference but could someone explain this a little better to me? Thankfully the wrench also has nm on it, but the range of it isn't what I had expected it to be due to my error of not knowing there was a difference. All of the wrenches I can find on US websites and in store are foot-pounds and I can't find one that is pounds-foot. I'm going mad.


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Torque is the product of force (lbs, newtons) and distance from the fulcrum (inches, feet, meters)

So the units are ft lbs, pound feet, inch pounds, newton meters etc.

Its all the same thing
 

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Discussion Starter #5
Nothing.

What's the difference between 2 x 6 and 6 x 2

Well that's what I thought, however in the service manual it states that the torque value for the oil drain bolt, for example, is "30 N•m (3.1 kgf•m, 22 lbf•ft)".
So my torque wrench that is 20-150 foot-pounds should be able to do the job if lbf•ft and foot-pounds are the same thing. However, when looking at the N•m markings on the same wrench, it starts at 33.9, which would put this wrench 3.9 N•m above the value needed to tighten this properly.


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Huh dude when stuffs in nm i just ask my android what 10 nm to foot pounds and it tells me. Same with inch pounds etc..
 

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Its just a scale. It probably has lbft one side and nm on the other correct? I bet it has lbft on the front and nm on the back right? So to get the zero line on the nm division you need to turn the handle half a turn up from the ft lb scale. To keep the linearity with both scales using the same divisions on the handle, the nm scale will have to be offset vs the lbft scale

Got it? If your wrench does 20-150 then set it at 22 and get it done
 

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I wouldn't necessarily trust a 20-150 wrench to pull 20lbs accurately. It's probably gonna be tighter than 20
It's suggested to only use the within 10% (might be higher but then it'd be a waste of a torque wrench amirite?) of the limit
 

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Discussion Starter #13
Well... Given the original post I think its relevant.. Dont you?

I don't think it's as clear as you make it out to be. There seems to be a fair amount of mixed opinion on the Internet as well. Some saying they are totally different, while some saying they are the same. I seem to think they are different since the conversion doesn't match up on the bottom unit of the torque wrench.


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You can be as skeptical as you want, torque is the product of force and distance. Only the units can change. If you use pounds as your unit of force and feet as your unit of distance then it doesn't matter in the slightest how you multiply them together, the result is the same.
 

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So I got a torque wrench a few months ago and noticed that the units are "Foot-Pounds" and the service manual I have gives the units in "lbf-ft", so pounds-foot I assume. I see there is a difference but could someone explain this a little better to me? Thankfully the wrench also has nm on it, but the range of it isn't what I had expected it to be due to my error of not knowing there was a difference. All of the wrenches I can find on US websites and in store are foot-pounds and I can't find one that is pounds-foot. I'm going mad.


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You're good dude, the person that wrote the ad isn't the engineer that designed the wrench.




Right, but what is the difference between foot pounds and pound feet?


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...semantics




I wouldn't necessarily trust a 20-150 wrench to pull 20lbs accurately. It's probably gonna be tighter than 20
It's suggested to only use the within 10% (might be higher but then it'd be a waste of a torque wrench amirite?) of the limit
I've heard the middle 75% is what they should be used for; so 12.5% above the lower limit and 12.5% below the upper limit.




You can be as skeptical as you want, torque is the product of force and distance. Only the units can change. If you use pounds as your unit of force and feet as your unit of distance then it doesn't matter in the slightest how you multiply them together, the result is the same.
I'm not trying to start a debate on this but 1/3 is not the same as 3/1...can we agree it's just semantics?
 
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