torque specs Nm vs. ft. lbs.

[Alan Cottrill]

so I'm torqing my case together for the 3rd time tonight, I think this may be the last time!

I'm looking at my torque wrench and I notice something odd.

all along I've been using the Nm torque values from the book, however this time I noticed the ft-lb value and it stuck in my head. So as I'm torqing my case nut to 35Nm, i notice it's not even close to the 25.8 ft-lb spec that is listed next to the 35Nm in the book.



so...is my torque wrench wrong or the book wrong?

[Jim Sims]

1 Nm equals .7375 ft-lb so 35Nm is equivalent to 25.81 ft-lb. Looks like one of the scales is off on your wrench. Jim

[ChrisBennet]

Is that one wrench with two scales on it? If so, wow, that's really bad! Sears should have a "recall" on that wrench. That evil!
-Chris

[Jim Sims]

Looking at the image again; the indicator could also be bent or cocked. Those beam type torque wrenches can be a bit fragile. Cheers, Jim

[Alan Cottrill]

this one is a brand new 3/8 drive dual sacle wrench. I bought it because the majority of the torque values i'll be using will be in the middle of the scale on this wrench.

well I've been playing with it and looking at the scales real close and I've noticed that the scales catch up with each other in the higher ends of the scales.

at 90Nm it lines up a hair past 65 ft-lbs which is correct
90*.7375=66.375

so I started looking real close at the scales. at the low end of the Nm scale it's really bunched up and as it goes higher up the scale the hash marks spread out. the ft.lb marks stay consistant across the scale.

so then I got out my old trusty 1/2 drive beam type torque wrench that only shows ft lbs. and went to work on some lug nuts comparing it's readings against my new craftsman.

the ft.lb readings on my old wrench were exactly the same as the ft.lb readings on my new wrench when torqing the same lug nut at various torque values. so my conclusion is that the Nm scale on my new wrench is meaningless it was probably added in a half a$$ed attempt to offer more "features" to the consumer.

[Alan Cottrill]

now I realize that my rod bolts can't possibly be torqued correctly becuase I was using the Nm scale on this wrench.

would I be out of line to ask my local sears store to buy me a new set of bolts?

[Jay Auskin]

You need to see if the Nm scale is correct, or the Ft-lbs scale produces the proper torque. Maybe you are Ok???

[Pat S]

ARRRG!
I just checked the one I used to build my engine with 1000m ago. And it is wrong too!!!

I had an old clicker but didn't want to use it since it was a few years old and had not been calibrated, so I bought the beam one. No I appearently have an engine full of undertorqued nuts/bolts...

Where do we sign up for the class action law suit