Lb Ft vs Ft Lb

Started by Conman, 01-20-2017 -- 11:43:56

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Conman

Calling all educated Metrology professionals. I'm attempting to explain the difference between Lb Ft vs Ft Lb. These abbreviations have been used interchangeably but they are interchangeable. I'm searching for documents pertaining to the differences and how these terms should be used.

Bryan

Six of one, half a dozen of the other.

briansalomon

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PurelyNonsense

I use the LbFt term only because the formula is Torque = Force * Distance. Same as pressure pounds per square inch kind of deal. I think it doesn't matter either way because there is no order to operation for that formula. Saying Foot Pounds is easier :)

ck454ss


WestCoastCal

Check out NIST SP811, pages 64-65, MOMENT OF FORCE or TORQUE section

kasah

FtLb is a unit of work.  LbFt is a unit of torque. 

griff61

Quote from: ck454ss on 01-23-2017 -- 07:30:30
Potato....Potaaaato

MOMENT OF FORCE or TORQUE dyne centimeter (dyn · cm) .................................. newton meter (N · m)....................................... 1.0   E−07
Guide for the Use of the International System of Units (SI)



65


To convert from   to   Multiply by

kilogram-force meter (kgf · m) ............................ newton meter (N · m).............................. 9.806 65   E+00
ounce (avoirdupois)-force inch (ozf · in).............. newton meter (N·m).............................. 7.061 552   E−03
ounce (avoirdupois)-force inch (ozf · in) ............. millinewton meter (mN · m) ................ 7.061 552   E+00
pound-force foot (lbf · ft) ..................................... newton meter (N · m)............................ 1.355 818   E+00
pound-force inch (lbf · in) ................................... newton meter (N · m) ........................... 1.129 848   E−01

MOMENT OF FORCE or TORQUE, DIVIDED BY LENGTH
pound-force foot per inch (lbf · ft / in) ................. newton meter per meter (N · m / m) ..... 5.337 866   E+01
pound-force inch per inch (lbf · in / in) ............... newton meter per meter (N · m / m) ..... 4.448 222   E+00
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briansalomon

From Wikipedia - "The name "pound-foot", intended to minimize confusion with the foot-pound as a unit of work, was apparently first proposed by British physicist Arthur Mason Worthington.[1] However, the torque unit is often still referred to as the foot-pound (ft·lbf)."

So if I understand correctly I could describe the leverage applied through a fulcrum as Ft/Lbs but tourque is going to be Lb/Ft.
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CalLabSolutions

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