Torque Wrench Question (1 Viewer)

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After totally disrespecting my trusty Husky torque wrench I got a new one (not Husky). I read this little tidbit on a torque wrench FAQ:

"Torque wrenches should be "exercised" a minimum of three times at 100% of full scale before use"

Has anybody heard of this?
 

Devilmans Hand

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That's new to me. I'd think that if it were the case then that would be done at he factory. Maybe this has something to do with the spring memory. My craftsmen torque wrench didn't say anything of the sort.
 

Devilmans Hand

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Pulled from wiki under torque wrenches.
"If a micrometer tool has been stored with the setting above 20% the tool should be set to 50% of full scale and exercised at least 5 times before being used"
I couldn't find any other mention of this method. I assume clutch/click type in op.
 

Devilmans Hand

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Well, they know their product best.
My engineer boss said that break-in is normal and store the tool on whatever setting that the
manufacturer recommends, somewhere between 0-20%.
He said to do the break in as a function check with click type torque Wrenches.
 

StaleAle

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After totally disrespecting my trusty Husky torque wrench I got a new one (not Husky).

What brand did you buy? I was about to purchase a Craftsman on sale awhile back (two actually) and a guy in the store advised against it. He had just returned his brand new one that was way, way out of adjustment and couldn't be calibrated. Said he found lots of threads online with similar problems so he decided to return instead of trade in. I haven't done the research myself though, just passed up the sale and bought other tools I needed that day (couldn't leave empty handed you know...).
 

Devilmans Hand

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da mn
I just bought a craftsman torque wrench for an axleshaft job. I'll have to research those problems now.

*Researched a bit and found mixed reviews. The naysayers seem to abuse their tools. See linky, the best one so far Best $100 Torque Wrench?

the fist post references the other common set of negative reviews.

I just bought a craftsman digitork in 1/2 and it seems to work well... :wrench:
 
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What brand did you buy? I was about to purchase a Craftsman on sale awhile back (two actually) and a guy in the store advised against it. He had just returned his brand new one that was way, way out of adjustment and couldn't be calibrated. Said he found lots of threads online with similar problems so he decided to return instead of trade in. I haven't done the research myself though, just passed up the sale and bought other tools I needed that day (couldn't leave empty handed you know...).

Jon:

Got a CDI torque wrench from a guy that sells them new on ebay. I went for the 10-100 ft-lbs model for $112 with free shipping. Excellent price considering other on-line retailers are about $140. Here's the link - CDI TORQUE WRENCH 1002MFRMH 3/8" DRIVE, 10' - 100' LBS. - eBay (item 140325979235 end time May-05-10 07:09:39 PDT)

- Dave
 
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When it comes to any automotive measuring tool, it pays to take good care of them and in my opinion, it pays to have two of of them or at least take the time to compare them to another one on a regular basis if you can't get them calibrated.

Snapon can check your torque wrench and military bases have tools to do as well. A friend once lost the motor on a race bike (and the race) because of a bad torque wrench and only uses Snapon after that experience. I'm not willing to pony up that much cash and I don't have a exotic race bike so I just double check my tools against others.

Timing lights and meters can cause similar havoc. I once pulled a perfectly good F motor out of my Cruiser because of a WAAAAAY out of calibration timing light and recently a bad meter lead me to believe that I had 120 volts on a 220 line. I found after I pulled and tossed that F motor that I just had a bad timing light. I put another back and it after setting the timing, it too ran badly so I borrowed and cross check the tool and it was off.

I've also seen bad vacuum gauges, hand held tach's, dwell meters, compression testers, etc. Once my friend Will was about to pull the motor out of a truck for having low compression, he was doing the test incorrectly and had a gauge that read low - in fact it had perfect compression and just needed a tune up. Do your diagnostics first with tested tools before you start tearing things apart! At first do no harm as they say.

I have some older craftsman torque wrenches and a Utica one. The latter has been calibrated. For what I do, that have served me well.

Last point, when you do torque something, don't bounce against the measurement because each time you hit that click it goes up a bit. Does not matter on a wheel but on something with threads in aluminum or a gasket that will be distorted, it does matter.
 

Cruiser804

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I have 3 Craftsman and have never had an issue with any of them. Now I have never rebuilt an engine but I have rebuilt axles, installed suspensions, brakes etc..

John, outside of the miliatary bases and SnapOn are there any other ways to test a torque wrench?
 

Devilmans Hand

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You can always put It in a vice and hang weights off of it. There should be some YouTube vids of this. Just do a few calculations. I've only tried this with beam type though.
 
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You can mike the bolt and measure how long it has stretched. So you torque a fastener to what you think is X inch/foot pounds or Newton Meters and then measure how long the bolt is with a micrometer compared to how long it was before it was under tension. Release the tension and re torque with another wrench and compare the difference. You might be able to find a table somewhere on how to do this. This is how they build bottom ends when they blue print engines, much more reliable that a torque wrench because the resistance of threads can affect torque readings but not bolt stretch.

Being a hillbilly myself, I just torque one bolt down, make a mark on it. Back it off a few turns and then see if I get back to the same place with a different wrench. When it comes to blueprinting motors, nice tools are great but you can accomplish a lot with simple tools and tricks. Plastiguage is a great example of this - such a simple but reliable tool for measuring bearing tolerances. You have to develop a "touch" or "feel" for things and learn to rely on that. My dad's friend who is a guru engine builder taught me this 26 years ago and it has done me well. Recently he build a vintage race motor for Jay Leno. Cool guy.

Remember all of the variables, if you have resistance on the threads then you won't get a fair measure of torque, if the bolt is too long if if there is oil or grease in there with no where to go then you will actually get hydraulic resistance and not a real torque value.

A good example of this is bike spokes. The DT Swiss brand uses rolled threads where as Wheelsmith brand uses cut threads. The rolled threads are superior in regards to accurate torque because the cut threads have a resistance not found in the roll threads that makes them feel tighter. However the cut threads do hold tighter but that is what locktite is for. A thread lube must be used with the cut threads to get an accurate reading.

I've seen many situations where cheap fasteners galled and gave an incorrect high torque reading but had little bolt tension/stretch and therefore less clamping force. Galling, like fret corrosion if fascinating stuff and both apply to fasteners.
 
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That's exactly what my friend says who lost his race motor...it was only one mis torqued bolt that fragged the whole motor and trans...and lost a race. From that point on, he only uses Snapon.
 
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John, I agree that "precision" is a good proxy for "accuracy", and the method you've outlined appears to reduce the number of variables. I thought about doing that with my neighbor's torque wrench but I figured I have a good excuse to buy a better torque wrench. :) I asked one of the engineers at work and they send their equipment over to the Calibration and Testing Branch for re-calibration. I couldn't get him to volunteer to send my wrench. :doh:

Unfortunately, Snap-On torque wrenches are out of my price range, especially for a half-assed shade-tree mechanic. I thought about getting one cheap on Ebay and then sending it out for re-calibration, but even on Ebay they're expensive.
 

OTRAMM

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Dave, We've got to introduce you to the evils of the tool truck. At twenty bucks a week on the truck account Barb will never know what sweet tools you're buying. You know you want the vibrating digital Snap On.
 
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Ryan, if the tool truck stopped in my neighborhood I'd be broke. Like kid in a freakin' candy store. You know it's bad if you're financing tools and you're not even a professional!

Bob, leave my private life PRIVATE!
 

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