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| Torque Wrench calibration certification http://warbirdinformationexchange.org/phpBB3/viewtopic.php?f=26&t=28097 |
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| Author: | SPANNERmkV [ Fri Feb 20, 2009 12:39 pm ] |
| Post subject: | Torque Wrench calibration certification |
Anybody got any recommendations as to where (in the US of A) to get torque wrenches re-calibrated and certified? |
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| Author: | skymstr02 [ Fri Feb 20, 2009 12:57 pm ] |
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Aztec Bolting Service, Inc. - League City, TX Manufacturer, Service Company http://www.aztecbolting.com/txseries.htm Company Profile: Minority owned torque wrench calibration & repair services. Bolting, stud removal, bolt torquing & tightening & rental services are also available. |
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| Author: | SPANNERmkV [ Fri Feb 20, 2009 2:11 pm ] |
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thanks Skymaster They are right down the road from us. SPANNER |
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| Author: | Sully [ Fri Feb 20, 2009 2:19 pm ] |
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I was able to get one micrometer "calibrated" and then use it for comparison of all other units to document their calibration. Of course any that did not pass would be sent out. It was my PMI who suggested this process to reduce cost. In short, torque wrench calibration test sets are not that expensive (or you can build one) and you can check the tester against a "calibrated" unit prior to certifing the rest in house. Sully |
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| Author: | SPANNERmkV [ Fri Feb 20, 2009 2:29 pm ] |
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hmmm... I LOVE WIX! I am tempted to have each and every wrench sent out so it has a certified ticket stamped, but that is a good technical tip in case we get pressed for time at some point. Thanks Sully! SPANNER |
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| Author: | Sully [ Fri Feb 20, 2009 2:38 pm ] |
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I wrote the process into the Approved QA manual. I then made my own calibration stickers and filed a spreadsheet with the documentation. Calibrating one out of forty units we maintained sure made sense to me. Sully |
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| Author: | A2C [ Fri Feb 20, 2009 10:59 pm ] |
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Quote: Anybody got any recommendations as to where (in the US of A) to get torque wrenches re-calibrated and certified?
There's a place in every town. Sort of like saying what grocery store do I go to? |
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| Author: | The Inspector [ Mon Feb 23, 2009 12:32 am ] |
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It's a good practice to send your calibrated tools out at least every year for re-certing. If you drop a torque wrench it's an unsafe practice to use it until it's been to a metrology company or lab (every medium sized and up town or city should have several like a commercial scales company) to be sure it is still in calibration, it's standard practice (and required policy) @ Boeing to turn in dropped calibrated measuring equipment and everything is on a calibration time schedule usually 1 calender year. I about crap whenever I see DISCOUNT TIRE installers 'torque' the lug nuts on a wheel then toss and slide the torque wrench across the shop floor. I also want to jump over the couch watching shows like 'HORSEPOWER' on SPIKE seeing the assembler blazing away and double, triple, or more torquing rod or main bearing bolts!! One smooth, continuous pull until the wrench clicks ONCE is the correct application of torque to a bolt. Clicking the wrench (seems to be a standard automotive practice and ALL WRONG!) more than once now puts the torque on that fastener somewhere well above whatever the recommended range was, causing excessive clamping forces and unnatural forces on the bolt, nut, and part being torqued. If you are installing a castellated nut and cotter pin, there is a torque range' from lowest minimum to maximum allowable, start at the lowest permissable torque and sneak up on the hole for the cotter pin, don't blaze away to the top of the range and wonder why the hole won't line up. A simple trick for cotter pins that are on shimmed bolts (like flap tracks or landing gear pivots) where the hole won't line up after correctly shimming the nut and torquing it, go get another nut! They ain't all made exactly the same so another castle nut will probably cure your problem. NEVER NEVER NEVER add 'just a skosh' or back off on a recommended torque to make things line up, play around with washer stackups and /or spacers to get the correct gaps and torques, take your time! It's only lives you're messing with and are you being paid piece work? Also, never drop below approximately 20% of the wrenches low range marking or above about 90% as the readings will be pretty far out of range. The most accurate torque wrnches you can use are the old standard dial type, they are above 98% accurate because they are direct reading. Digital, or 'click' types can vary wildly (even the really expensive ones sold by the guys in the big red and white or yellow and white tool trucks, some won't calibrate, just what you want after spending over $200 on one and donot use it until it has been checked for calibration) and for the sake of your own sanity, NEVER attempt to use the Newton Meter scale on the back of the wrench shaft, it'll make you crazy trying to figure out how many cubic hectares are involved in tightening something (it' a French plot, they hold THE certified, calbration kilo in a locked vault, has anyone ever seen it? How can we be sure?) |
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| Author: | The Inspector [ Mon Feb 23, 2009 2:08 am ] |
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Cable tensiometers can be checked by hanging standard sizes of Stainless control cable in a corner of the hanger with a known and marked modest weight attached to one end. Change blocks for various diameters of cables and do a quick check to be sure your tensiometer is in range, the cable won't stretch enough in your kids' lifetimes to affect the readings as long as the weight isn't that old 454 Chevy block your brother in law blew up! 
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| Author: | SPANNERmkV [ Mon Feb 23, 2009 8:19 pm ] |
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Thanks INSPECTOR... While I was doing most of what you were writing about the one thing I never thought of... was go get another nut and see if it was threaded differently. I had a funny incident where the supervising A&P came in and took over a pulley set-up installation (so I could go be Wing Leader about something) and I had told him it looked like we needed two thin washers instead of two thicker washers in order to make the cotter pin fit. When I got back later he was doing the second fit with...ta da... the two skinnies. But it was good that he proved to himself that it was the correct combination rather than slapping it together just cuz I said so. |
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| Author: | Cvairwerks [ Tue Feb 24, 2009 6:27 am ] |
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Something else about torques....Read the manual about the procedures for a particular installation. I've got a couple of weird ones at work and it took some severe discussions with a fellow employee to get him to understand that there was a specific reason for those instructions. Two good examples for you: 1. Our axle nuts are torqued to a specific value with the wheel being rotated continously. Stop the rotation, back the nut off clear of the spacer ring and retorque to the final value while rotating the wheel, which by the way is half of the original torque. Now align the keeper, using enough torque to make the alignment, but not to exceede a certain additional torque value or rotation of the nut....clear as mud right?..... 2. Torque to running torque plus a certain amount....ie if it takes 30 inch pounds to run the nut down, then the torque is 30 plus the incremental amount...and it won't be exactly the same for every nut/bolt combination. In other words, you have to set the torque value individually based on what running torque you have for each combination. It's a tough go trying to convince some of the guys that because one took a specific running value, that they all will take the same value. There are a number of others too but you can get the drift. Oh yeah, don't forget that values for lubed or dry threads are also going to change the numbers. The books are your friend 
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| Author: | The Inspector [ Tue Feb 24, 2009 1:12 pm ] |
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Cvairwerks- Thanks for adding those great bits of info, #1 usually (but not always) involves seating and torquing wheel bearing races during tire changes (lotsofun on a 47). And I forgot to mention run on torques, and that was a great and simple explanation of the processes on both types |
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| Author: | SPANNERmkV [ Fri Feb 27, 2009 2:10 pm ] |
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Thanks Cvairwerks and Inspector... I have done a fari amount of torque wrenching, but not on rolling stock, so to speak. And by the way. As far as grocery stores... We have good ones and bad ones here in Houston, so it is not at ALL unreasonable to ask which grocery stores are to be avoided at all costs!
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| Author: | krlang [ Sun Mar 01, 2009 7:58 am ] |
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Hmmm, Last week I bought a 3 3/4" socket to do main wheels on a G-550. It was listed on Amazon for $25, I couldnt resist it. It kills me to adapt a 3/4" drive socket down to a 1/4" torque wrench. 
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| Author: | The Inspector [ Sun Mar 01, 2009 9:39 pm ] |
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GOOD BUY!!! Just for S's & G's, ask the guy in the Rip Off..er Snap Off van what his socket is worth, I'll bet you could take the Missus to a fancy dinner with the price difference |
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