Torque Wrenches - Advice Please

[dgc333]

My first job out of college in the early 70's was developing torquing procedures for jet engine assembly at Pratt & Whitney. What I learned during that first 6 months of my engineering career was using a torque wrench to tighten a threaded fastener is not a good way to obtain consistent and accurate clamping force. That is why in critical applications where accurate and repeatable clamping force is required torque to yield fasteners or bolt stretch is measured.

That being said I recommend that folks not get hung up on the accuracy of a torque wrench and this is definitely not an area that you get your monies worth by spending more. Not long ago Hot Rod Magazine did a comparison of torque wrenches from cheap to several hundred dollars and it was a $39 Harbor Freight digital unit that attached to a rachet that won for being the most accurate and repeatable over time.

Personally I like to use a beam type torque wrench when I have room and can see. For quick and dirty things like lug nuts I use a click type. I have an in-lb dial type for setting up rear ends when you need to measure torque to establish bearing preload.

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[Optimum Performance]

Your point being?

I apoloize, no disrespect intended, you can only "exercise" instruments that have a conventional ratchet head. Some instruments can have the calibration effected by break-away torque shock.

 

[IPOGT]

:ranton't use harbor freight torque wrenches. Ask me how I know. Just don't.
You're welcome in advance.

 

[dgc333]

And yet when tested monthly over a 6 month period of time it maintained it's accuracy and repeatability better than all the others tested.

 

[jasonstang]

Anyone have suggestions for something higher quality than a $50 Techton but not as crazy expensive as the Snap-on for $480 ??

I have craftsman.

 

[mikeD4V]

My recommendation is the Snap-On Techwrench Digital Torque Wrench.
They are available in 25-250 ft-lbs, 1/2 inch drive and 10-100 ft-lbs, 3/8 inch drive.
We use these daily in our shop.
Some fasteners require accurate torque.
Every fastener I touch is torque per the book.
Spend more and get a quality wrench IMO.

+1

I have the 3/8 techwrench digital and it's money well spent. You can find them used (found mine for $250) but try to have it cal'd after purchasing. I had the snap on truck at a dealership do it since the tools are warrantied for life.

5-100lbs is pretty much all you'll need and the 3/8 flexhead is small enough to get in there and do hard to reach spots like sway bars. I'm not in the automotive trade but do enough work to justify (IMO) a pricey tool.

 

[VinnAY]

I wouldn't get a torque in 3/8 drive, I don't have a well reasoned explanation for it but I'd only 1/2" drive on that one though I'm sure a 3/8 would be fine for most anything in the car owner realm. Also, given that our wheels spec to 150, I'd get that rating, nothing less. Case in point some of the IRS bolts (if you did get under there) are rated @ 129ft lbs.

 

[rob_s]

Since no one has mentioned it yet, I went with the Kobalt and have zero complaints

http://www.lowes.com/pd_337334-22328-85602_0__?productId=3381202

 

[HavasuCat]

Just getting a 1/2 drive is great if all you do is chassis/suspension. But for anybody willing to take on the task of wrenching on their machine it would make sense to invest in all three drives. Remember all fasteners are rated ( torque/load ) and to keep the integrity up to standards you need the right tool.

 

[highvoltage]

Have me a Craftsman that works great.

 

[RSPEC-015]

Thanks for all the responses guy, it's been very helpful.

Most likely going to get the Gorilla 150ft-lbs one.

 

[GTP]

What bugs me is when I follow someone else's work where they obviously over-tightened the fasteners. I don't care if it is a car, or a CT scanner, or a small screw into a plastic boss holding a clamshell case together. Some guys just tighten things too much. :tsk:

For smaller fasteners, there is seldom need for a torque wrench.
For medium size fasteners (3/8 drive), either it is still not that critical, or a drop of blue threadlock does the trick. (Example - blue threadlock on 15mm socket cap screws tighten w/o TW to secure Steeda jacking rails.)
For larger and/or critical-purpose fasteners, yes, use a 3/8"- or 1/2"-drive torque wrench. You want the bolt to stretch the proper amount.

We really should develop the feel for when to stop twisting the wrench.

 

[mrblanche]

And yet when tested monthly over a 6 month period of time it maintained it's accuracy and repeatability better than all the others tested.

If I recall correctly, it was the little add-on unit that tested so well, wasn't it? Not an actual wrench?

http://www.harborfreight.com/12-in-drive-digital-torque-adapter-68283.html

Of course, since the OP in this thread is in Australia, it may be a moot point.

And the magazine test. http://www.hotrod.com/how-to/additional-how-to/ccrp-1304-torque-wrench-testing/

 

[mustang_guy]

I believe they got the read out for the Hf so they had a digital read out like the snap on to see how accurate it was together. They didnt clarify if the read out made or break the accuracy. Id hope if it did they'd specify. Btw i already posted that test from hotrod

 

[HavasuCat]

Thanks for all the responses guy, it's been very helpful.

Most likely going to get the Gorilla 150ft-lbs one.

I would look into at least 200 Ft-lbs rating or higher.
Wheel lugs @ 150 Ft-lbs. Your wrench would be maxed out.

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