Torque Conversions

[Jack Suber]

Question for those of you with technical expertise: If I have a torque wrench that is calibrated for "inch/lbs" can I assume that 12 inch/pounds equals 1 ft/lb? I need to torque something to 7 ft/lbs and my ft/lb torque wrench doesn't "click" below 10 ft/lbs. So, I was wondering if I could set my in/lb torque wrench to 84 in/lbs and get the same torque?

A friend told me to make sure that the conversion is that simple. These are bolts going into the engine block (aluminum)of my 4-wheeler so I don't want to screw them up. Thanks.

Edited August 9, 2006 by Jack Suber

[Matt Cheely]

You are correct.

84 in/lbs should work.

But if it breaks it's not my fault

Edited August 9, 2006 by Matt Cheely

[Hank Ellis]

You're on the right track. 1 ft/lb = 12 in/lb In this example, 7 ft/lb = 84 in/lb.

Even large big bertha torque wrenches use in/lb to accurately torque items. The main rotor mast nut (jesus nut) of a Bell 206 is torqued to 3000 to 3300 in/lb (250 to 275 ft/lb) and the torque wrench we use is marked in in/lb. When you get to big cajones torque like the Bell 407 mast nut (600 or 800 ft/lb depending on mast configuration) then we go with a torque multiplier. Easier than going with an eight foot long wrench to smoke the nut down. FWIW: We also have an inch/ounce torque wrench for securing windshield screws. 1 in/lb = 16 in/oz.

If you happen to work on items that give a Metric torque value in Newton/Meters, then your conversions are:

1 Nm = 0.737 ft/lb

1 ft/lb = 1.356 Nm

[back to your regularly scheduled shooting forum.]

[EricW]

Torque = r X F = r*F*sin(angle)

will get you whereever you need to go.

If you ever forget, remember the joke:

Q: What do you get when you cross an elephant with a grape?

A: Elephant-grape sine theta.

[George]

Yes, 12 inch lbs is the same as 1 ft lbs of torque

[Jack Suber]

Thanks, guys. I just wanted to make sure before I did something stupid.

[ChuckS]

Hi all,

I can't believe that I failed to share this here . Check out this link. I have been using this for years. You can find just about anything here.

Martindale Center

It's all good stuff but Calculators On-Line Center (Over "22,025" Calculators On-Line) has been real handy!

[bountyhunter]

my ft/lb torque wrench doesn't "click" below 10 ft/lbs.

FYI, I own about five torque wrenches and the two that are "click" types don't have my confidence or respect. I checked their calibration using the beam deflection wrenches and the click ones are VERY inaccurate at lower settings.... and have an "offset" compared to the scales printed on the shaft of the wrench all the way up the range.

I don't even use the click ones any more, just stick with the deflection wrenches.

[Flexmoney]

In the Air Force I worked on instruments, auto-pilot, navs systems, etc...somehow, that meant we calibrated/tested all the torque wrenches too.

From that experience, I don't have much faith in torque wrench settings.

Not that it matters, many don't know how to use them properly anyway.

(And yet...planes stay in the air and cars don't fly apart going down the road.)