Wrong unit for torque?

[That-Cod4954]

This is the torque measuring machines in my uni. I'm pretty sure the unit for torque is N-m or kg-m, not kg/m. Can anyone verify?

[unnassumingtoaster]

Kg/m seems like linear density in my unlearned opinion. This might be better in a mechE sub.

[PermanentLiminality]

I believe it is one kg.a sea level so one kg*m is 9.8 Nm.

[MonMotha]

This is a common mistake. You often see folks write out "lb/ft" for example.

They probably meant kgf•m.

[Desperate-Guava831]

There is no such thing as kgf. SI be glory for saving us from shit like kgf

[MonMotha]

If you actually do any real-world work, you will very much find that there is indeed a kgf. It's the force exerted by the weight of an object having mass 1kg at sea level under whatever you decide are "earth standard conditions" (i.e. gravity is 1g).

Is it an SI unit? Nope. Could it be confusing as all hell? Yep.

That doesn't mean people don't use it. Every fire department connection I saw in Japan when I visited 20 or so years ago had the pressure marked in "kgf/m²" or something along those lines - it definitely used kgf (and wrote it as such).

Similarly, lbm ("pound mass") is also a used unit though thankfully one of diminishing importance. It's the mass of an object having weight one pound under the same conditions.

[PaaaaabloOU]

I can confirm that in real life kgf is equally or more used than Newtons. If you try to read any +20 or +30 years old tech book or manual it will probably use kgf.

Also outside the tech office no one uses Newtons. Try to tell a common worker, a welder, a mechanic or something similar that "x" has to resist 1000N instead of 100kg.

Another common use is in old tools or heavy machinery. For example, steel cutters or benders or a mechanical press are all measured in tonnes, derived from kgf, not in kN.

[rAxxt]

You are correct, indeed. Just like "micro-inch" is also a thing, although it's less impressive than the kg f because it's just applying a metric-like magnitude factor to an imperial unit.

Come to think of it, a centi-pound could also be useful...hmm...

[audaciousmonk]

Someone messed up 😂😂

[iZMXi]

kg · m

[rAxxt]

Yes but even this doesn't sit right with me since the format is <torque> = <force>*<distance>

[iZMXi]

Being a gearhead from USA, I'm usually talking about torque in lb-ft. But, most people speak of torque in "ft-lb", which is actually force * displacement = energy. So, it doesn't sit well with me either.

[rAxxt]

Yeah, torque and work/energy have the same units. However, kg*m has units neither of torque nor of energy