What's a torque wrench?

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Actually I know what it is, but I am not sure I am using it correctly.
I replaced a blade on my lawn mower, and I was trying to tighten the bolt to spec, which is between 400 and 600 ft lbs. Well, I set my torque wrench to 500 ft lbs, and I was hoping to hear the "click" that tells me I got to destination. But it's been a while since I used a torque wrench, and I am not sure what I should be hearing anymore. Can you help? When I try to give it another 1/4 turn I hear something, but it's not a full blown click. Does this make sense? Yet, I don't want to go any further and overtighten or even break something
For what it's worth, I was able to unscrew the bolt with the same setting on the torque wrench. I am thinking that maybe this tells me that if I exerted more or less the same force to unscrew it as I am in tightening the bolt ... I should be okay.
Any help is appreciated.
Claudia
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Set the wrench to something real low (100?) and turn the bolt that has been tightened to 500. The noise you hear should be the noise you expect ...
Claudia wrote:

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Not necessarily true. Some torque wrenches require that you approach the correct torque for the click to occur. If you have already exceeded it it will never occur.

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Art wrote:

You seem to be saying that if a bolt has already been tightened 50 foot pounds and I put a torque wrench on it set to click at 30 foot pounds and then start pulling on the wrench, I *won't* get a click when I reach 30 foot pounds of torque?
That would take a pretty smart wrench, wouldn't it?
Or, did you just miswrite what you meant to say?
Jeff
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click a second time. Perhaps this is the behavior he was attempting to describe. The statement is nonsense in almost any other context.
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wrote:

Or if a mechanic first uses a regular wrench then checks the torque and he previously overtorqued it with the regular wrench, the torque wrench will never click. That is how a torque wrench I own works according to its instructions. You must approach the correct torque with the torque wrench. It cannot detect an already overtorqued nut.
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Sorry, I don't buy that. How does the torque wrench know the difference between these two situations?
a) force applied to the handle is gradually being increased up to the set point as the nut turns slowly, approaching the correct torque
b) force applied to the handle is gradually being increased up to the set point as the nut remains stationary, having already been tightened beyond the correct torque
What model of torque wrench is this, that is smart enough to tell the difference between the two situations? You say that's how it works "according to the instructions". Have you actually tested it, to see if that's how it works _in_practice_? Please post the section of the instructions that describes this amazing behavior.
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wrote: | >> >Art wrote: | >> > | >> >> Not necessarily true. Some torque wrenches require that you approach | >the | >> >> correct torque for the click to occur. If you have already exceeded it | >it | >> >> will never occur. | >> > | >> >You seem to be saying that if a bolt has already been tightened 50 foot | >> >pounds and I put a torque wrench on it set to click at 30 foot pounds | >> >and then start pulling on the wrench, I *won't* get a click when I reach | >> >30 foot pounds of torque? | >> > | >> >That would take a pretty smart wrench, wouldn't it? | >> > | >> >Or, did you just miswrite what you meant to say? | >> > | >> On my torque wrench, if you ignore the click and keep pulling, it does not | >> click a second time. Perhaps this is the behavior he was attempting to | >> describe. The statement is nonsense in almost any other context. | > | >Or if a mechanic first uses a regular wrench then checks the torque and he | >previously overtorqued it with the regular wrench, the torque wrench will | >never click. That is how a torque wrench I own works according to its | >instructions. You must approach the correct torque with the torque wrench. | >It cannot detect an already overtorqued nut. | | Sorry, I don't buy that. How does the torque wrench know the difference | between these two situations? | | a) force applied to the handle is gradually being increased up to the set | point as the nut turns slowly, approaching the correct torque | | b) force applied to the handle is gradually being increased up to the set | point as the nut remains stationary, having already been tightened beyond the | correct torque | | What model of torque wrench is this, that is smart enough to tell the | difference between the two situations? You say that's how it works "according | to the instructions". Have you actually tested it, to see if that's how it | works _in_practice_? Please post the section of the instructions that | describes this amazing behavior.
I am finding out more about torque wrenches than I had intended. <LOL> Now boys, keep the discussion civil, ok?
Claudia
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Claudia wrote:

That could be the understatement of the century <gt>
Now boys, keep the discussion civil, ok?
Whole bunch of people on Usenet with not a whole lot to do, lots of time on their hands, if'n you get my drift.
It's best to get in, get your answer, and bail out. Eventually, this thread will spawn 1 or 2 flame wars and at least one discussion of the election and the war in the middle east.
Run now while the gettin' is good!
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It is an inch pound torque wrench and yes, unfortunately it was tested by overtorquing and ruining a bunch of expensive fasteners that were already past the measurement point due to an unsupervised inexperienced worker. I didn't consider it a feature..... I considered it a design flaw..... but I guess from an engineers point of view it is a feature since the torque wrench cannot be blamed for the mis-measurement and over torquing. Lack of proper use caused the problem. It was made by SK Handtool Corporation http://www.skhandtool.com/ though I don't see the exact model in their on-line catalog. It is 2 years old. Just dug it out of my garage so I could answer your post. The instruction explicitly say to never torque a fastener that is already tightened. Loosen it first. In our experience if you don't do that with this model wrench it will never click.
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In other words, it's broken.

Yep. Lack of proper use.

Did you ever try that with a new one, that hadn't been abused?

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It is working exactly as designed. If you tighten the item with it it clicks when torqued correctly. If the item is already overtightened it is useless as it should be. It is designed to get you to the correct torque. It is not designed to tell you that the fastener is torqued greater than it was supposed to be.
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Art wrote:

Huh? Sure it will. If the nut doesn't turn (torqued higher than the wrench is set for), the torque wrench clicks when your pull exceeds the torque it is set for. Set a wrench for 50 foot pounds and pull on a nut that is torqued any amount higher than 50 foot pounds and it will click. The click tells you that the nut is torqued at or more than 50 foot pounds.
Of course you are right, the click doesn't tell you anything about the torque of the nut, unless you keep setting the wrench higher and when it finally moves the nut you know the torque WAS the previous setting.
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snipped-for-privacy@streamfaith.com says...

handle (which I doubt) it would take 250 lb. of force to get 500 ft. lb. of torque.
Are you sure it isn't 500 INCH pounds??
Rick
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says... | > I replaced a blade on my lawn mower, and I was trying to tighten the bolt to | > spec, which is between 400 and 600 ft lbs. Well, I set my torque wrench to | > 500 ft lbs, and I was hoping to hear the "click" that tells me I got to | > destination. | > | That sounds very high to me. If your torque wrench had a 2 foot | handle (which I doubt) it would take 250 lb. of force to get 500 ft. | lb. of torque. | | Are you sure it isn't 500 INCH pounds?? | | Rick
You are right. The manual calls for "in lbs" not "ft lbs." As I look at the wrench, I see the "foot" designation, however. I was naively looking at hundreds of foot lbs instead of (what it turns out to be) tens of foot lbs. Therefore (wheew!) I must have set the wrench at 50 ft lbs _not_ 500 ft lbs. I think that 50 ft lbs is equal to 600 in lbs, which is the upper limit shown in the manual. So, I should be okay.
Now, if I could just hear that click ...
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Claudia wrote:

If you want to crank the living sh*t out of it, sure you will!

Back it the fu*k down!...FULL SPEED REVERSE! Is any of this sinkin' in yet? ( $1 Foghorn Leghorn )
OK, quick easy math here: 480 in lbs = 40 ft lbs You know..."480" as in "something nice and in the middle of your suggested range."
Loosen it, re-tighten to 40 ft lbs. You'll hear the click.
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snipped-for-privacy@streamfaith.com says...

the "click" models have little pin at the far end of the handle that pops out when it clicks.
Rick
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says... | > Now, if I could just hear that click ... | > | It shouldn't be very loud. Kinda like a clipping a nail. Some of | the "click" models have little pin at the far end of the handle that | pops out when it clicks. | | Rick
I have heard that "click" before. Since I don't quite hear it now, and I am scared to death that I may damage something, I am thinking of backing it down to a lower setting first, as suggested by someone else.
Thanks again.
Claudia
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says...

its unclear whether or not you have taken previously given advice. set the thing to 1 foot pound. something low so you dont have to mess around. if it doesnt click or snap or otherwise easily identify when you've put the proper force on it, its broken.
randy
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says... | > | > I replaced a blade on my lawn mower, and I was trying to tighten the | > bolt to | > | > spec, which is between 400 and 600 ft lbs. Well, I set my torque | wrench | > to | > | > 500 ft lbs, and I was hoping to hear the "click" that tells me I got | to | > | > destination. | > | > | > | That sounds very high to me. If your torque wrench had a 2 foot | > | handle (which I doubt) it would take 250 lb. of force to get 500 ft. | > | lb. of torque. | > | | > | Are you sure it isn't 500 INCH pounds?? | > | | > | Rick | > | > You are right. The manual calls for "in lbs" not "ft lbs." As I look at | > the wrench, I see the "foot" designation, however. I was naively looking | at | > hundreds of foot lbs instead of (what it turns out to be) tens of foot | lbs. | > Therefore (wheew!) I must have set the wrench at 50 ft lbs _not_ 500 ft | lbs. | > I think that 50 ft lbs is equal to 600 in lbs, which is the upper limit | > shown in the manual. So, I should be okay. | > | > Now, if I could just hear that click ... | | its unclear whether or not you have taken previously given advice. set the | thing to 1 foot pound. something low so you dont have to mess around. if | it doesnt click or snap or otherwise easily identify when you've put the | proper force on it, its broken. | | randy
I have not yet set it to a lower torque.
Thanks.
Claudia
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