For those that are ex Navy....you will understand this. Just got a AFTO 22 approved that is going to stop gages +/- 0.5% or better being checked every 10%. Though only if it's not used as a standard to calibrate other gages. Haven't seen a 3112 yet so i think this is a good thing.
Also being changed is the fact of setting the UUT to nominal and reading the standard.....does not apply to the 10-10525 though.(It is however being replaced) No more limitations on gages that are in their tolerances. Just wish we could get gages....basic process gages from having to be excersized three times....they use em at a pressure setting....so it's just a waste of N2 for pnuematic gages.
Just be happy we don't have to check them in the downscale direction....
Good point and I am happy about not having to check them downscale. That would make alot more out of tolerance gages.
Oh yeah... I've just been DYING to NRTS something for Hysteresis...
I did get to NRTS something for hysteresis the other day....an Altimeter. I was so happy. I hadn't written a tag out for that in So Long, I almost wrote Survey and replace on it.
"Survey and Replace"..... I sure do miss that phrase.
Just out of curiosity, does anyone else out there cite the source data on the cal label for the stated accuracy of pressure gauges, torque wrenches, screwdrivers, thermometers, etc.?
I can assure you folks that I shower daily.
The reason I ask is because of an unmarked change in 2014 that I came across a while back. We have contacted AFMETCAL and are trying to determine if the statement was changed in error or not marked in error. We haven't received a response as of yet.
What was the error Aaron???
A sincere thanks for the reply MIRCS.
But skip it...it's not important.
There are better things to do than trying to force this stuff on people.
I think I'll just lurk like everyone else.
Back to work...
OK, Gauges are calibrated IAW (Navy) NAVAIR17-35CR-WSY-1, (Air Force) TO 33L1-4-3961 and (Army) TBUSASG PHY 12: Calibration Requirements for Pressure Gauges.
As per Appendix A, Section 2. Supplement Information, Para 4. Second sentence states:
"Exercising is recommended for gauges used as standard to minimize the effects of hysteresis on a Bourdon tube or other pressure-responsive element and to maximize performance."
As far as checking every 10% test point, see Table 1, Test Sequence 1.0 Item b.
Hopefully you'll take this chance to research Calibration Requirement Documents (CRDs, to fully understand why you're doing what you're doing. :idea:
Have a sparkling day.
InLikeFlynn
OK...you are SCARING me.
First question: are you posting just so you can be the big man on the block?
Second question: I've heard of all these little critters, lemmings, jumping off these cliffs, just 'cause they do it that way, should you?
Third, a statement: PMEL, Precision Measurement Equipment Laboratory, what part are you having a hard time understanding?
PMEL technicians are probably the smartest group of people I know, but when someone like yourself make erroneous statement "Checking the gage in the way the customer uses them" I kinda get worried." Just 'cause I saw some dumbass blow himself up using the wrong meter to check a live GCU...the procedure told him which one to use, or how about the dumbass that inflated a tire using a Hipack...8000 psi in to an aircraft tire, let's just say he's DEAD also...do you want to be known as the PMEL tech that did it "the WRONG way"? I can go on and on about what the customer does....OUR job is to make sure what we calibrate is done by the numbers...there are reason for US to do this!
I 100% agree that excercising 3 times should not be done on AC scales and pressure gages because they are not used that way. They need to be accurate the way they are commonly used, not the optimum way that PMEL can calibrate it too.
BTW how many people excercise the 3682 King before using it? You know I checked it out once, and it does make a difference in accuracy.
Im kind of the "New Kid on the Block" with this forum but I have to agree and disagree with what is being said. I understand the point of exersizing a pressure gage and not exersizing. The main reason for calibration procedures is to ensure uniformaty in a calibration however it is done. It is also calibrated in a way to ensure the greatest accuracy and repeatability of readings. I know I was tought in PMEL that if I cant repeat a reading than the reading isnt any good. If calibrations were done on equipment how Calibration Techs think they are used I would hate to see how much variation between techs and labs there would be. As a customer I would wonder who was right or who was wrong. People have stated the customer doesnt flex the the pressure gage before they use it so why do it. What if that pressure gage is used used from no load to 90% load a hundred times a day. Do you always know how a gage is used or is going to be used?
He might be the new kid, but he makes a good point. My chief at Ramstein said almost the same thing, verbatim: "You don't know how the customer uses the gear, so calibrate it by the procedure, every time."
I also figured I was just a young buck sargeant, and the K-procedure writer was probably a lot smarter than I was, and had thought about some of those things, like how a Simpson 260AFP-1 gets pegged by some E-1 comm troop because they never remember to put the knob on the right range setting before running a few hundred volts through it...
When we did torque wrenches at F.E.Warren AFB, we always exercised them 3 times- something about "warming up" the spring inside, gave you reliable, repeatable readings. God only knows what the missile techs did with them when they left the shop, but when they left the lab, they worked fine.
Being an ex navy IM we always excercised our Standards and our TI's. This way if your Standard or TI has problems during excercising you can nrts or reject if nessasary check for leaks etc.. before getting into calibration. For example if you were calibrating an KNC 3112 you could very easily slam the low side and crush the bourdon tube if the blocking valve wasnt set right. And you would see that in exercising if someone before you jacked it up. Trust me, it can and has happened alot. If you follow the T.O. you cant go wrong.
I'm interested in knowing what the root cause would be InLikeFlynn and Velasco would try to use in explaining why their non-exercised pressure gage failed the MLC audit, and in turn caused their lab to not be certified. Then try to explain to the auditors that you didn't follow the T.O. because you are a hot-sh!t PMEL tech who knows more about the equipment, how it should be used, how the user uses it, how it should be calibrated, and more than the AFMETCAL TCM who rejected your AFTO 22s to remove the exercising option because you are a friggin moron.
Air Force calibration intervals are established so that 85% of the test equipment coming back for calibration will still be in tolerance. So if you don't want to exercise it, why don't you use your same level of integrity and just put your stamp on the cal label without even checking it? You have an 85% chance it will be good, you really don't want to calibrate it according to the T.O., go ahead...hot stamp it. That's what you are really doing anyway; when you don't follow the T.O.
All you have to do is look at what all the gage manufacturers have as calibration procedures. Look at some specifications.....the ones that say +/- 1% Full scale after being taken to full scale...1, 2, or 3 times. Look at never doing hysterisis checks on gages.......alot of manufacturers have additional accuracies for hysterisis and repeatability.....so a 1% gage might really be a 1.25% gage and people are calibrating these gages at a tighter tolerance than what the manufacturer states.
You know, I was going to post something very informative, but it was semi-rude and would not have helped the process here....and from reading a past post...I'm told that I am too uptight...or something like that, so I decided to....condense the whole thing for everyone.
Prove to me a better way of doing it (taking into account the approximately 3543 P/Ns, oh and let's not forget 6-428, 6-430, and the rest of the T.O. that have analog gauges in them...Test Cell so on and so forth), along with ALL the PMEL labs personal....and I'll see if I can get this fixed, just remember, you have to follow all the rules of AFMETCAL TO Guide & Requirements, PHY-12_33L1-4-3961_Pressure-Gages, and Mil-Prf-38793B...along with the BIO STYLES guide and about 8 or 10 people here....
It can be fixed, don't complain about it, give me examples that I can use as ammo...and GOOD usable information to FIX it, and I might be able to help...heck...give me reliable manufacturers data that doesn't conflict with itself.
and remember...you are NOT the PMEL police...keep your lab coat on, enjoy the climate control, and let the wrench turners do whatever they do, right, wrong or indifferent, if they screw up, it will be no reflection on YOUR integrity!
Quote from: Phys_dim on 03-24-2006 -- 11:50:19
keep your lab coat on, enjoy the climate control, and let the wrench turners do whatever they do, right, wrong or indifferent, if they screw up, it will be no reflection on YOUR integrity!
Well said!
In the lab, we do it by the book. Sometimes the book is stupid, sometimes whoever wrote it don't speaka too gooda English, sometimes the book makes no sense at all. But we do it by the book. I have no control over what happens to the gear when it leaves my bench, but when it leaves my bench, it works as advertised, guaranteed. ...and if I can't fix it, it aint broke.
As a calibration tech(14 years exp) And I know that a lot of you have more exp than I but I can tell you that on a 2% or worse pressure gages exercising the gage will NOT have any effect on the performance of that gage, because you are talking about a gross number, most gages will not read down to the accuracy listed and will have to be taken out to one division (100 psi X 5 psi div, with a tol of ±2% the best readable is ±2. 5psi or 1/2 div. read 33k6-4-428-1 p3. 2 ) of course this is using dead weights not APC"S (just bought one and I can't for the life of me figure out why I didn't sooner) However on the "TEST" gages you will see an error on the gage and it should be exercised and cleaned before cal depending on the range of course.