Torque wrench left improperly torqued

[David Ragan]

Not knowing any better, I left my HF small torque wrench (in-lb model) in the drawer for about 5 years, at the 50lb mark.

So, I was reading a thread here and ran across where someone said, more or less, not to do that.

:eek:

What have I done? Do I need to spend yet another $30?

How can I tell if it is still any good?

[Bruce Page]

Yeah, you should never leave them set like that. I don't know of an easy way to check it other than comparing it against another torque wrench. It would cost more than it's worth to have it re-calibrated. I would not trust it for anything critical.

[glenn bradley]

If it is any consolation, your thread made me go check my little C-man that I use for my carbide inserts. I had stored it as per the instructions but, could just as easily NOT have done that. Thanks!

[James Nugnes]

What was the bottom of the scale for the t-wrench you left at 50? I have a pretty big one and 40 ft/lbs is the bottom of the rang for that one.

[Steve Rozmiarek]

I think that is a myth invented by some ocd addled drill instructor wannabe machinist. I bet it's just fine. I've personally never seen one go out of spec from that, as checked by the snap-on guy. I have seen one ruined after a bone head used it for a breaker bar though. Purely circumstantial evidence with bigger ones, but I wouldn't loose sleep.

If you want to check the calibration, a quick rig with a know weight on the end of a lever of know length as moved by the wrench, will be pretty darn accurate. Or go find the snap-on truck.

[David Ragan]

Bring my HF to snap on guy? Ha ha
i will leave @ my friends shop tho so *he* can have snap on guy check next time truck is there

[Robert Parent]

With a coupon you can get another at HF for about $10..... It's a good idea to have several around just to check them against each other now and then. Thus far I have not experienced any real problem with leaving them with some torque during storage. I am sure it is not the best for them, but at $10 I just don't worry all that much about it. Heck, using one that is slightly off is much better than using none at all which is what most folks do.

Robert

[Myk Rian]

I think that is a myth invented by some ocd addled drill instructor wannabe machinist..
Agreed. We had a scale repair department at work for over 30 years, and they certified our T-wrenches. NEVER did they say that was necessary.

[Ken Fitzgerald]

Before I retired, I had a set of torque wrenches that had to be calibrated annually. We also had to take a class in using them. We were taught to reset/release the tension on them each time after you are done using them.

We were also taught to not "reef" on them until you see the correct tension or hear the "click" because overshoot is quite common and the amount of overshoot can be pretty dramatic. Rather, we set the wrench to 1/2 the desired torque, ease on it until that value is reached; complete that step on all related fasteners, then set to the final value and gradually apply pressure to "ease" to the final value on all related fasteners. Finish with all respective fasteners (bolt or nut). Do not go back and check as it usually results in causing over tightening.

A lot of what I just stated was demonstrated during the class with students doing the torquing and then instructors measuring and demonstrating the overshoot or improper values.

While actual torque values are important, IMO, in most cases what is important is equal torque on related bolts/nuts such as lug nuts or head bolts etc.

Torque becomes very important in some cases like the newer CT scanners. Imagine when you are laying on the patient pallet being scanned, there is an x-ray tube that can weigh as much as 350+lbs. and in some cases it is spinning around your body at speeds of 3 revolutions per second..... If that tube comes off at that speed, BAD THINGS CAN HAPPEN. There were torque specifications for every bolt, screw and nut holding every component on that rotating frame.

Torque can be important.

[Bruce Page]

I think that is a myth invented by some ocd addled drill instructor wannabe machinist. I bet it's just fine. I've personally never seen one go out of spec from that, as checked by the snap-on guy. I have seen one ruined after a bone head used it for a breaker bar though. Purely circumstantial evidence with bigger ones, but I wouldn't loose sleep.

If you want to check the calibration, a quick rig with a know weight on the end of a lever of know length as moved by the wrench, will be pretty darn accurate. Or go find the snap-on truck.

It's not a myth. Before retiring I worked in aerospace & missile defense assembling rocket motors and payloads. I had 2 drawers full of Snap On torque wrenches ranging from newton meters to foot pounds that were calibrated on a yearly recall schedule. Our calibration lab was NIST certified. If they fell out of tolerance +/- 4% they were repaired or replaced. They can go out of calibration even if well taken care of.
If you are torquing the inserts on a cutting head it's probably not a big deal if it's out of spec a little. If you're assembling a flight termination system it is.

[David Ragan]

So, as far as technique is concerned, torque to half the final value, once-when the wrench clicks once, stop and move on, torquing all bolts (of same function). Then repeat process at full torque. Do not repeat pricess a second time on any given bolt

[Bruce Page]

What is it you are torquing? Generally, you only need to do step torquing if what you are torquing can deform, for example an engine cylinder head.

[David Ragan]

What is it you are torquing? Generally, you only need to do step torquing if what you are torquing can deform, for example an engine cylinder head.

its just the Shelix head/carbide inserts for DW 735 planer..... Looking for rules of the road

[Mike Cutler]

As someone that calibrates torque wrenches, and the standards they're tested against, to NIST certifications, You probably didn't do much harm to that particular quality level of torque wrench. Relax it, and run it up the scale with some torques a few times to make sure it works throughout the scale.
I have no idea what is on the Snap-On truck, but it's probably a more than adequate, simple torque analyzer. If you can get it checked out that way, that would be pretty cool.

Ken and Bruce are correct. ISA and NIST mechanical standards practices for torque wrenches are to leave them relaxed to the bottom end of the scale. ( We'll leave out the long term temp and humidity requirements though. ;)
You're not trying to launch a space shuttle though, just looking for uniform torquing.

[Ken Fitzgerald]

Ken and Bruce are correct. ISA and NIST mechanical standards practices for torque wrenches are to leave them relaxed to the bottom end of the scale. ( We'll leave out the long term temp and humidity requirements though. ;)

You're not trying to launch a space shuttle though, just looking for uniform torquing.

Bingo!

For torquing carbide inserts on a Shelix head, it's probably good enough.

[Bruce Page]

its just the Shelix head/carbide inserts for DW 735 planer..... Looking for rules of the road

No, you do not need to step torque something solid like that. I worked a number of years as an "ocd" machinist :) and never torqued a carbide insert with a torque wrench. I never had one come loose but I did snap a few screws.. :rolleyes:

[Rod Sheridan]

Not knowing any better, I left my HF small torque wrench (in-lb model) in the drawer for about 5 years, at the 50lb mark.

So, I was reading a thread here and ran across where someone said, more or less, not to do that.

:eek:

What have I done? Do I need to spend yet another $30?

How can I tell if it is still any good?

Worrying about accuracy with a $30 torque wrench is like bringing a second 5 pound extinguisher to a forest fire............Rod

[Ken Fitzgerald]

What is it you are torquing? Generally, you only need to do step torquing if what you are torquing can deform, for example an engine cylinder head.

Bruce....when I left Chicago, my fellow FEs referred to me as "Delta Gorilla":eek::o..... Delta-scan was the trademark....... I have snapped a few screws. That's why I use torque wrenches on things like the carbide bits in my jointer.:o

[David C. Roseman]

Not knowing any better, I left my HF small torque wrench (in-lb model) in the drawer for about 5 years, at the 50lb mark. [snip]


David, if it's the 1/4" model HF currently sells, the torque range is 20 to 200 in/lbs. http://www.harborfreight.com/1-4-quarter-inch-drive-click-type-torque-wrench-2696.html If you left it set only at 50 I doubt you did much if any damage. But if you have a local HF near you, why not just take it in and ask the manager on duty to help you test it against one of their new ones? The managers at the two stores nearest me are so willing to help, I'm sure they'd be happy to do that here. You could take something along with fasteners on it, and some sockets, to use for the test.

David

[Bruce Page]

Bruce....when I left Chicago, my fellow FEs referred to me as "Delta Gorilla":eek::o..... Delta-scan was the trademark....... I have snapped a few screws. That's why I use torque wrenches on things like the carbide bits in my jointer.:o
I had a shop foreman once who accused me of being a gorilla. It's a story I can't repeat on a family forum but I still laugh whenever I think about it!

[Tyler Keniston]

anyone use beam types. No worries there ;

[Steve Rozmiarek]

Worrying about accuracy with a $30 torque wrench is like bringing a second 5 pound extinguisher to a forest fire............Rod

LOL, that sounds just like an argument the snap-on guy will give you to buy his wrench instead of testing the HF one ;)

Ken, I've done an informal "test" on head bolts based on the technique you described to properly torque. You are so right, you can really mess up a torque spec just by being too quick, or by rechecking.

[Larry Edgerton]

A lot of the new stuff is a torque number and X number of degrees. Said to be more accurate. I always did Kens method of half torque then on to the final number.

I want one of the newer SnapOn's that talk to you and have a degree calculator built in. Even if yo can not get the full stroke it will let you know when you have gone the required degrees.

[Ole Anderson]

I am pasting this response from the original, now off topic, thread here: This was my original link to the torque wrench review: http://images.harborfreight.com/hftweb/in-the-news/CarCraft-0413.pdf Yes, it does read like an ad for HF, could be they sponsored the review?


Big surprise -- that link takes you to the Harbor Freight website. I wouldn't put too much faith in a single test result like shown in the magazine article. Quality control at Harbor Freight has been well-discussed. Sometimes you get lucky, sometimes not so much. Ask Boeing or Lockheed-Martin whose torque wrenches they use. Hint - it's NOT Harbor Freight. I buy disposable brushes to clean tools, and zip ties at HF, but my torque wrenches I buy from Snap On.

At least HF didn't do the testing. Not uncommon at all for manufacturers to use magazine reviews in their advertising. I think we are all aware that finding a true test of any equipment isn't going to come from a magazine. Case in point Dust Collectors. But having some review to me is better than none at all. No magazine could afford to do a statistically sound review. I was just surprised that the HF TR was as accurate as it was and wanted to share. I have three torque wrenches, two of them are Craftsman DigiTork (3/8" and 1/2"), the other a cheap MIT 3/8" one that I have preset (yea, I know) for my Jeep's driveshaft U-joint bolts which gets removed each time I tow it to FL or up north. Not everyone is willing or able to buy SnapOn, let along aerospace quality tools. And frankly, few applications require the difference in accuracy afforded by those expensive tools.

Interesting that if you read the article, it references a digital strain gauge that HF sells that can be used to check your torque wrench accuracy, if you believe their review. At $30 I might just have to get one: http://www.harborfreight.com/12-in-drive-digital-torue-adapter-68283.html I have a few HF tools, not many.

[Shawn Pixley]

That's what I have. Never had the new, fancy kind.

[Chuck Wintle]

where I work the person in our in house calibration lab advised to release the pressure on a torque wrench setting when not in use.

[Ken Fitzgerald]

I had a shop foreman once who accused me of being a gorilla. It's a story I can't repeat on a family forum but I still laugh whenever I think about it!

Bruce, my nickname's reason for being can be discussed on a family friendly forum.

Back when disk drives were huge and heavy, some of them weighed in excess of 230 lbs. One Chicago winter day in deep snow, I drove to the United Airline freight terminal at O'Hare where I had a disk drive in a wooden crate loaded into the back of my company Chevy Citation via forklift. When I got to the hospital, a guard helped me load it out and onto a hand truck. Long story shortened, I changed that 230 lb. disk drive by myself using one of those old mechanical screw type adjustable height desk chairs to remove the old disk drive and install the new one. I never did lift the entire weight of the disk drive. I did tip it up and walk it to the end of the crate but never actually lifted the entire weight. The other FEs working that night were all tied up working elsewhere in the city. A while later I paged them to let them know it was changed out, I was loading software and no assistance was needed. Then I became "Delta Gorilla".

If it had been in any other model CT scanner I couldn't have done it as the disk drive in that one was near the bottom of the cabinet.

They never asked and I never told them I didn't lift that heavy rascal!

[John Coloccia]

50 in-lbs is a bit over 20% full scale reading of 200 in-lbs. That's not an unreasonable place to leave it. I doubt it did much, if anything, to the calibration. Torquing bolts isn't an exact science. It's really just a poor substitute for measure bolt elongation, which is what you REALLY want to do, but it's completely impractical for most applications. It's affected by technique, precisely where you hold the wrench for click type wrenches, friction, etc.

If you REALLY want to just check the calibration, you can hang a weight dead center on the handle, and see where it breaks. Obviously, you'll have to calculated the torque at the hanging point to find the right weight, but it's just a lever....no problem. Personally, I'd maybe try that once just to make sure it's still in the general ball park after sitting for 5 years, and then I'd just forget about it and use the thing.

I think I have about 5 torque wrenches here. I use them for all sorts of things. If I can find a torque spec, I use the torque wrench. Most bolts just require the Guttenteit technique.