Bad torque wrench readings

hkpierce

'02 140 Hi BlueBlk Pass
I had suspicions that my no-name 3/8 click torque wrench was not correct after some damage to the van that should not have happened if.... .:cry:

So after the fact I tested it on my bench. Allegedly the range is from 10 in/lb to 800 in/lb (0.8 ft/lb to 66.7 ft/lb).

Capture.JPG
When I adjusted the adjustment screw for accuracy at 10.5 ft/lb, the reading for 39.55ft/lb was 56.25ft/lb.

Time for a new torque wrench. While I have not done it yet, I think I will look for one that has a narrower range of values, and not a no-name.

My last job I used a torsion torque wrench which was both easier and quicker to test its calibration, even it its exactness was not equal to what a "click" might be.
 

lindenengineering

Well-known member
I had suspicions that my no-name 3/8 click torque wrench was not correct after some damage to the van that should not have happened if.... .:cry:

So after the fact I tested it on my bench. Allegedly the range is from 10 in/lb to 800 in/lb (0.8 ft/lb to 66.7 ft/lb).

View attachment 120988
When I adjusted the adjustment screw for accuracy at 10.5 ft/lb, the reading for 39.55ft/lb was 56.25ft/lb.

Time for a new torque wrench. While I have not done it yet, I think I will look for one that has a narrower range of values, and not a no-name.

My last job I used a torsion torque wrench which was both easier and quicker to test its calibration, even it its exactness was not equal to what a "click" might be.
For professional reasoning I send all my torque wrenches out for industry recognized industry written certification. Cost is between $85 to $105 per test/certification.
Dennis
 

rollerbearing

Well-known member
It's also easy to check yourself if you have a vise and a luggage scale.

Clamp the square drive in the vise (rotational axis vertical). Measure the distance to the center of the handle (in feet for ft lbs). Hook the luggage scale over the handle at the center (the same spot you measured to) and pull perpendicularly. Note the luggage scale reading when wrench clicks.

Distance in feet times scale reading in lbs = ft lbs torque

https://www.amazon.com/Samsonite-77...&pf_rd_p=7524a643-2f53-5b85-9796-c77c2419e221


They also have strain gauge digital luggage scales for not much more.

You can check the scale by weighing something with it - 5 gallons of water - some other object you know the weight of - something you confirmed on a bathroom scale etc.

Not NIST level but a whole lot better than nothing. I usually always check mine before working on something important. I don't bother when I use it for lugs nuts etc.
 
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Larry M

Member
For professional reasoning I send all my torque wrenches out for industry recognized industry written certification. Cost is between $85 to $105 per test/certification.
Dennis
Cheap considering the consequences. Is there one brand that has has been more accurate out of the box than others?
 

lindenengineering

Well-known member
Cheap considering the consequences. Is there one brand that has has been more accurate out of the box than others?
No!
In fact I have always swearn by Snap On & made in the USA, BUT, someone gave me a clone Snap On like wrench made in China.
Believable or not it has been the most consistent and reliable for years.
Makes you think again when you get surprises like this.
Dennis
 

smiller

2008 View J (2007 NCV3 3500)
No!
In fact I have always swearn by Snap On & made in the USA, BUT, someone gave me a clone Snap On like wrench made in China.
Believable or not it has been the most consistent and reliable for years.
Makes you think again when you get surprises like this.
Dennis
I've now seen two separate tests comparing a Snap On and Harbor Freight wrench (the high-line Icon models, not the $12.99 job) and in both cases the HF unit was both more accurate and more consistent. One of the tests also had a tear-down comparison and the HF seemed at least the equal of the Snap On, at least visually, so while one could speculate that 'the Snap On lasts longer in pro service' I'm not sure what objective evidence there is to back that up.

It's a changing world. There will always be China junk of course, but they are also very successfully performing manned space missions and landing rover probes on the dark side of moon so I wouldn't be too quick to dismiss Chinese technology. As an aside, I wonder what brand torque wrenches they use? :smilewink:

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irvingj

2015 RT SS Agile (3.0L)
Some on this forum may be old enough to remember a time in the 50s when "Made in Japan" was actually synonymous with words like "cheap" and "junk".

By the 70s that was no longer the case, in fact their autos, stereos and cameras were world-class quality and very much in demand. Twenty years.

For better or worse, I believe China will get there in a similar fashion-- not really there yet (I still mostly avoid their products), but getting closer. They may have already nailed down the solar panel controller market....

As far as torque wrenches, yes, I've sent mine (one a 30-year-old Craftsman) out to a company called "Team Torque" to have them calibrated. PITA, but necessary if they're to be trusted.
 

Midwestdrifter

Engineer In Residence
In the airline industry we have mostly moved to digital torque wrenches. Easier to calibrate and more accurate, even at very low or high torque settings. They also don't suffer from temperature sensitivity like some designs can. Almost all digital units use an integral load cell. There are disk shaped units which you can attach to an existing breaker bar, ratchet for more flexibility in handle length.
 

lindenengineering

Well-known member
In the airline industry we have mostly moved to digital torque wrenches. Easier to calibrate and more accurate, even at very low or high torque settings. They also don't suffer from temperature sensitivity like some designs can. Almost all digital units use an integral load cell. There are disk shaped units which you can attach to an existing breaker bar, ratchet for more flexibility in handle length.
All of our torque wrenches for vital stuff like engine & transmission rebuilds atc are digital. That stated they still get sent out for certification annually.
Dennis
 

Bobnoxious

Adeptus Trollarium
Some on this forum may be old enough to remember a time in the 50s when "Made in Japan" was actually synonymous with words like "cheap" and "junk".

By the 70s that was no longer the case, in fact their autos, stereos and cameras were world-class quality and very much in demand. Twenty years.

For better or worse, I believe China will get there in a similar fashion-- not really there yet (I still mostly avoid their products), but getting closer. They may have already nailed down the solar panel controller market....

As far as torque wrenches, yes, I've sent mine (one a 30-year-old Craftsman) out to a company called "Team Torque" to have them calibrated. PITA, but necessary if they're to be trusted.

That's cuz China is stealing our industry and military Secrets and sometimes with Google's and Apple's help. These corporations are treasonous sell outs. Just ask Nike.
 

smiller

2008 View J (2007 NCV3 3500)
For home use you can just use one of the digital torque adapters from Harbor Freight and others as a quick and pretty accurate test of your mechanical torque wrenches (just mount the adapter in a vise and twist away with the wrench under test) No, it's not exactly a NIST-traceable professional lab calibration so probably not suitable for pro use, but for home use they work quite well as a 'it's still ok' sanity check. FWIW all of my banged-around-for-years-and-never-calibrated Craftsman wrenches are still within spec.

If you don't like Harbor Freight stuff you can also buy these from several higher-end vendors, but I bet the guts are the same ;)


https://www.harborfreight.com/12-in-Drive-Digital-Torque-Adapter-63917.html
Capture.JPG

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Aqua Puttana

Poly - Thread Finder
We used load cells aka strain gauges in the metals furnacing/processing plants where I worked. Any scales and load cells which were related to weighing final products prior to shipping had a fairly strict calibration schedule. Many of those calibration schedules traced to commerce regulations.

The load cells on internal mix systems and other production equipment were on a less rigorous calibration check schedule. Even with less testing/calibration tweaking, the less tested load cells remained very accurate. The torque units suggested by Smiller are strain gauges.

As there are possible issues with torque wrenches, and some here may obsess. For DIY I would agree with Smiller that a portable strain gauge provides a reasonable calibration check. There is little need for DIY tools to trace to national calibration standards.

How many head bolts are you going tighten? TTY fasteners have a built in tolerance range. Eg. - Injector hold down fasteners discussions about torque with 90 degrees + vs 90 + 90 degrees recommended by some.

FWIW.

:2cents: vic
 

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