Torque Wrench Best Practices?

[giants]

Tonight, I installed new spark plugs and used a 5-80 ft-lb Horrible Freight Pittsburgh Pro Torque Wrench set to 13 ft-lbs after ratchet tightening to about 10 ft-lbs. The problem is the torque wrench kept moving past the 13 ft-lb mark. I knew enough to stop (experience is a tough teacher). The spark plug/cylinder head seems okay.

I tried the wrench on a non-critical bolt set to 10 ft-lbs with a Craftsman beam torque wrench: a headlight bracket bollt, and proceeded to break the bolt off. The next time I torqued with it at 10 ft-lbs, it was fine. I'm going to return it.

I have a 2004 Powerbuilt, subject of another thread, that I tested tonight and it didn't torque properly (I can't recall the value).

I also tested two other 1/2" Harbor Freights and almost damaged a lug nut thread.

Last month, I bought a Husky 3/8" torque wrench from Home Despot and maybe used is once or twice. Tonight, it's is off by 3 ft-lbs at 50 ft-lbs of torque (6%!). I'm exchanging it tomorrow morning.

Do I need to:

avoid Harbor Freight?
calibrate torque wrenches before each use?
set them when not in use to a value other than zero?

 

[Spacey_G]

It can be difficult to feel the click when you're near the bottom of the range. If you need to torque to 10 ft-lbs. you'd probably be better off with an in-lb wrench where 120 in-lbs is near the middle of the range (e.g. the CDI 2502MRMH 30-250 in-lb.)

 

[CR888]

mmmm...tough one, we either presume you abilities are good therefore the torque wrenches are faulty & blame HF or... you are not using the tool correctly. To he honest its hard to tell. What drive size TW are you using when breaking bolts when set @10ftlb?

 

[CR888]

I'd do some testing or practice on some non critical fasteners. Whether a torque wrench is working or not I am going to know if I'm compromising lug threads just by feel. My guess is your trying to use a big 1/2" TW to torque small low torque fasteners that would be better suited to use a 3/8" or 1/4" TW.

 

[Spacey_G]

Although the two are roughly related, it's the torque range that matters, not the drive size.

Using a 5-80 ft-lb. wrench, regardless of drive size, to torque a fastener to 10 ft-lbs. is not what I'd consider a best practice.

 

[GCS]

It can be difficult to feel the click when you're near the bottom of the range. If you need to torque to 10 ft-lbs. you'd probably be better off with an in-lb wrench where 120 in-lbs is near the middle of the range (e.g. the CDI 2502MRMH 30-250 in-lb.)

Although the two are roughly related, it's the torque range that matters, not the drive size.

Using a 5-80 ft-lb. wrench, regardless of drive size, to torque a fastener to 10 ft-lbs. is not what I'd consider a best practice.

^^
correct (this & this)

 

[Hawke]

Any torque wrench not calibrated is just a more expensive socket handle.

In my experience, most wrenches I test are plus or minus 30%.

 

[matt_i]

Imo for a torque wrench to be repeatable and reliable to a target value is fully dependent on the quality and condition of the internal mechanism (talking pure mechanical click wrenches here) and its Lubrication....if the mechanism is binding or has lots of friction then you are going to have issues.

 

[DFB]

I've experienced a torque wrench not clicking at its preset every now and then, and ya you do question why. Maybe the threads are stretching or the socket slipping slightly on a worn fastener head, sometimes operator error too.

Like posted above being a spring mechanism, friction binding may have a lot to do with it. I often like to work the adjuster up and down thru range a couple of times before torqueing especially if the wrench hasn't been used in a while. I have 2 Craftsman a 3/8" and a 1/2", plus a Taiwan made 1/4". but I do also have one HF, a 1/2" model seems to work ok within the range, again values are best in the middle as opposed to extremes top and bottom.

I have checked all the larger 2 against the Quinn digital torque meter (be nice they had one for in lbs also) and both are a very good match.

Lubrication makes sense but I have never oiled one though. I all honesty the HF one always seems quite stiff in the adjustment.

 

[rumb]

Never store torque wrench click type on 0! store it at minimum. I have Teng-Tools 20-110nM torque wrench, and it's need to be stored at 20nM. If lower, it's can be damaged. I compared it with beam type Park-Tool TW-2 - it's spot on in any reading from 20nM to 70nM.

 

[nieuport17]

A torque wrench did click soft on me once and I over torqued an oil drain plug because I didn’t feel/hear it.
Now I check my torque click wrench with a beam torque wrench before I start to make sure the correct torque is set and the feel of the click.
My suggestion is to connect two torque wrenches before a job so you know it’s not off. It only takes a second.

 

[Shadowdog500]

The odds of getting 5 inaccurate torque wrenches of three different brands and two different styles would be pretty low. I have access to a lab that has a torque wrench calibrator and do check my torque wrench on it before doing a critical torque and have never been more than a few ft lbs off. A few years ago I bought a HF torque wrench on sale to modify for a project. I tested it just to see how it performed. It was spot on until I got to the very top of the scale.

I'm not sure what you were doing wrong with the two torque wrenches you used on the lug nuts, but something tells me that it wasn’t the torque wrench. I couldn’t imagine anyone over tightening a lug nut to the point of damaging the threads while using a torque wrench or even a 4 way lug nut wrench. I assume most people would realize that they were pulling on the wrench way too hard long before the threads were damaged.

You may want to get with an experienced mechanic and have them watch what you are doing and give you some guidance. If you are interested in this type of thing I’m sure an experienced person would be willing to look over your shoulder. Is there a vocational school in your area that has adult evening classes? I took evening classes in welding and outboard engine repair when I was young and learned a lot and really enjoyed it.

I do agree that you used the wrong torque wrench for the 10 ft.-lb. bolt. You should buy an inch pound torque wrench that has the proper range for items like that. This CDI wrench would work for that. CDI Torque 2502MRMH 3/8-Inch Drive Metal Handle Click Type Torque Wrench, Torque Range 30 to 250-Inc https://www.amazon.com/dp/B004618UI8/?tag=atomicindus08-20

Hope this helps,
Chris

 

[javyLSU]

Never store torque wrench click type on 0! store it at minimum. I have Teng-Tools 20-110nM torque wrench, and it's need to be stored at 20nM. If lower, it's can be damaged. I compared it with beam type Park-Tool TW-2 - it's spot on in any reading from 20nM to 70nM.

^This. I've spoken directly to manufacturers of several different click-type torque wrenches, and they all said to never go below the lowest setting on the range shown on the torque wrench (i.e. if your wrench shows a range of 10-100, it should be stored at 10, and never be rotated below 10). Doing so can wipe out any calibration that was done at the factory or otherwise. I learned this the hard way about 20 years ago when I screwed up my first Craftsman torque wrench...

 

[giants]

mmmm...tough one, we either presume you abilities are good therefore the torque wrenches are faulty & blame HF or... you are not using the tool correctly. To he honest its hard to tell. What drive size TW are you using when breaking bolts when set @10ftlb?

Thanks. I use 1/4" socket with the 1/4" drive, 3/8" sockets with the 3/8" to work on the 10mm bolt, 3/8" on 3/8" on spark plug, and 1/2" with the 1/2" on lug nut.

I thought about my technique, which I've used without problems for 15 years, but I used the same technique with one that does work.

 

[visionguru]

Tonight, I installed new spark plugs and used a 5-80 ft-lb Horrible Freight Pittsburgh Pro Torque Wrench set to 13 ft-lbs after ratchet tightening to about 10 ft-lbs. The problem is the torque wrench kept moving past the 13 ft-lb mark. I knew enough to stop (experience is a tough teacher). The spark plug/cylinder head seems okay.

I tried the wrench on a non-critical bolt set to 10 ft-lbs with a Craftsman beam torque wrench: a headlight bracket bollt, and proceeded to break the bolt off. The next time I torqued with it at 10 ft-lbs, it was fine. I'm going to return it.

I have a 2004 Powerbuilt, subject of another thread, that I tested tonight and it didn't torque properly (I can't recall the value).

I also tested two other 1/2" Harbor Freights and almost damaged a lug nut thread.

Last month, I bought a Husky 3/8" torque wrench from Home Despot and maybe used is once or twice. Tonight, it's is off by 3 ft-lbs at 50 ft-lbs of torque (6%!). I'm exchanging it tomorrow morning.

Do I need to:

avoid Harbor Freight?
calibrate torque wrenches before each use?
set them when not in use to a value other than zero?

The problem is ..... YOU, a nightmare customer for TW sellers.
Solution #1: work on your technique

Harbor Freight torque wrenches are cheaply made, but surprisingly accurate, which means they were indeed calibrated before leaving factory.

3 ft-lb @50 ft-lb is not bad at all. If you don't go slow when approaching the desired torque, the torque value can have big errors, easily 70 ft-lb @ 50 ft-lb if you go quick and don't stop in time.

It's unlikely that any of your torque wrenches are bad or inaccurate. Your technique, or your reaction time is the reason.

Solution #2 get a digital
The beep, vibration, the light, and the real time torque display will definitely be big helps to you.

 

[RKA]

Well, with respect to using a 5-80 ft lb wrench on a 13 ft lb bolt, I've never found the low end particularly accurate, and have heard of plenty of instances where a bolt got over torqued. For any 3/8" wrench rated up to 80-100 ft lbs, the lowest I will use it is 20 ft lbs, then I switch over to a wrench marked in in lbs.

 

[paulsomlo]

Do I need to:

avoid Harbor Freight?
calibrate torque wrenches before each use?
set them when not in use to a value other than zero?

Learn to trust your wrist - the only time I use a torque wrench is on things that are critical; head bolts, suspension, lug nuts. Most of the time, it sits in the box.

Buy one good torque wrench, instead of five cheap ones - go to Tooltopia.com and buy a CDI split beam.

 

[Jacobson]

Operator error.

 

[ItsNemo]

A torque wrench did click soft on me once and I over torqued an oil drain plug because I didn’t feel/hear it.
Now I check my torque click wrench with a beam torque wrench before I start to make sure the correct torque is set and the feel of the click.
My suggestion is to connect two torque wrenches before a job so you know it’s not off. It only takes a second.

Uh, do you just keep yanking on it regardless?

It doesn't take long to get a fairly good sense of what a torque value feels like on the wrench. You can simply feel that you should be hitting the value within a range and if you keep going, something is off....reset and try again. On top of that there's the feeling of the bolt coming up to torque, it should progressively in a noticeable way start to feel tight and if it doesn't, you again may need to reset or have damaged threads.

Inexperience is FAR more often the problem with torque wrenches than the wrenches themselves.

 

[sberry]

Simple beam type. The main value in a torque wrench for general work is to learn a feel comparison. Motor rebuilding , routine rebuilding and valve jobs are about a thing of the past. So many guys learned the feel like this and today so many don't know the difference between 10 and 30. I got to work to remember the last time I used one,, rod bolt, head bolts to critical engine maybe, been years.

 

[sberry]

Living proof of this is above,, almost ruined a lug nut , wouldn't have been a problem breaker bar or ratchet.

 

[nieuport17]

Uh, do you just keep yanking on it regardless?



It doesn't take long to get a fairly good sense of what a torque value feels like on the wrench. You can simply feel that you should be hitting the value within a range and if you keep going, something is off....reset and try again. On top of that there's the feeling of the bolt coming up to torque, it should progressively in a noticeable way start to feel tight and if it doesn't, you again may need to reset or have damaged threads.



Inexperience is FAR more often the problem with torque wrenches than the wrenches themselves.

I probably torque to 40lb/ft instead of 30.
No, There are bad wrenches.