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quote:Hey Brent, Just a few thoughts concerning your well thought out post. I don't believe any of the Ammo Manufacturers will quote the specific "Pressure" they develop a Lot of Cartridges to. And, I don't believe SAAMI will supply their Calibration Ammo to anyone who is not running a Lab. I'm sure I've not "Edited Out" anything in this Thread. Perhaps it was in another Thread where we discussed this before. I'm in complete agreement with your last statement. It may not seem that I am since I do believe it is very possible to "mislead" a Beginner into creating a potentially Un-SAFE Load. How many times do you see a Beginner post something to the effect, "Need HOT Load for a xxx!" This site seems to be a bit better about warning them of such foolishness than most sites. Best of luck to you. | |||
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Alright, folks, this is fun, but...... It is utter nonsense. Why? Hot Core's basic, repeated assumption is that the brass is the weakest link in the system. That, all, is BUNKUM. Take a look at the following link. Look at the pictures, read the story and the explanation of what happened. THEN tell me the brass was the weakest link in the chain. http://www.securedsend.net/forums/showthread.php?s=&threadid=6708 We have had the opportunity to read the results of SEVERAL experimenters that state they have loaded up to 80,000 PSI without adverse effects to the brass. From the evidence presented in the link, it appears that under the right circumstances, you can actually go much higher than that. Dutch. Dutch. | |||
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I am having progressively more and more difficulty distinguishing this thread from the Humor section. You haven't "shot down" anything except the few remaining tatters of your credibility. quote:Ridiculous. That is the definition among quality professionals. quote:Absurd beyond belief. If you know an output variable (PSI) as a function of the input variables, as we do in this case, you know the output variable. News flash: On the macro scale, the universe is deterministic. Y=f(x1, x2,...xn). If you know the input variables and the functional relationship, you know the output variable. If you've done your homework, you know how big the error component is, too. And I do. quote:Yeah, sure. I only learned strain gauges from Bill Verhoef at Tektronix, back in '72. He literally wrote the book on strain gauges, and made me a present of a copy. quote:I'd be happy to compare a bibliography of my published articles on the subject with yours. quote:Gross ignorance on display. Actually, SAAMI cartridges would be only marginal valuable in calibrating a strain gauge system. Their pressures are known only when fired in chambers cut to minimum SAAMI specifications. They will typically run 2-3,000 PSI lower when fired in chambers cut to the middle of specifications. Strain gauge systems calibrated to the dimensions of your own rifle, and to the properties of steel do not have this bias. quote:Give me a break! I was that person. Now I teach those people, and make quite a good living at it. I also hold an ASQ Certified Quality Manger certificate, and I'm a six sigma Sr. Master Black Belt. I have patiently and correctly answered your questions for several posts. Now it is your turn. Anyone with even a fraction of the experience you claim can easily answer the following questions without the slightest difficulty. Please post your answers for all to see. 1. If a differential amplifier with a CMRR of 10,000:1 and a gain of 100 is connected to a balanced bridge circuit with a strain gauge as the active element, and an equal resistor in series, and if the voltage applied to the bridge is exatly 10 volts, what voltage will appear at the output of the differential amplifier? 2. While we're at it, what is CMRR, and why is it often critical in strain gauge applications? 3. What is the mathmatical definition of "gauge factor", as applied to strain gauges? 4. A gauge repeatability and reproducibility study is run on a measuring device. The repeatability and reproducibility do not add up to the total R&R. What is the most common cause of this? 5. What is the difference between accuracy and precision? 6. A strain gauge with a nominal resistance of 360 ohms is connected in series with a fixed resistor of 360 ohms. The input capacitance of the first amplifier stage is 100 pF. What is the fastest risetime available from this arrangement? 7. Two identical strain gauges with gauge factor .002 are connected in series, and biasd with exactly 10 volts. The multiplier resistors for the bridge are the same value as the nominal value of the strain gauges. Both gauges are simultaneously subjected to 100 microstrains. How much will the voltage between the junction of the two strain gauges the junction of the multiplier resistors change? There you go.... seven REALLY simple questions, for anyone that knows about measurement systems and strain gauges. At least two of them are laughably trivial. If you can get at least four right, including the two really easy ones, I will unflip your bozo bit in my database. [ 11-05-2003, 07:05: Message edited by: denton ] | |||
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I think Hot Core just shit his pants! ![[Big Grin]](images/icons/grin.gif){kind=icon} | |||
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Hey Denton, Excellent questions. I'll answer them the way you typically answer mine: 1. - 7. A duck can swim. Note it is a true statement, but has nothing to do with the questions. Or I could have used your old, "What questions?" ... I will say I'm amazed Tektronix has no concept of Calibration. Doesn't speak well for them at all. Really looking forward to seeing your Data on the PRE/CHE Tests - if they are performed correctly. You do have me wondering if that is even a remote possibility. | |||
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Red herring. | |||
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What is the sound of one bit flipping? | |||
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Hello, Info! Just for the record, once upon a time, I wondered if Info knew as much as he claimed. I posed some physics questions to him, which he accepted, and nailed perfectly. I then had the great pleasure of announcing to the world that I considered him a genius, a scholar, and an excellent judge of fine horses. I may disagree with him on some points, but I respect his knowledge. Unfortunately, we have no such opportunity for poor Hot Core. His bozo bit stays flipped. For the morbidly curious, here are my answers to the questions posed, give or take the present condition of my brain. 1. For the conditions given, both inputs of the differential amplifier are held at 5 volts. This is the common mode signal. The common mode rejection ratio is 10,000:1, which means that this produces an output equivalent to a .0005 volt differential signal. The gain of the amplifier is 100, so the output is .05 volts. 2. CMRR is common mode rejection ratio. It is the ability of the differential amplifier to reject a signal that appears simultaneously at both input ports. It is important in strain gauge applications, because strain gauges are often configured in an arrangement where a common mode signal is present. It is desirable that the amplifier ignore the common mode signal, and respond only to the differential signal. 3. Gauge factor is (delta R/R)/(delta L/L), where R is resistance and L is length. This is the basic sensitivity of the strain gauge. 4. Gauge R&R is expressed in terms of standard deviations. Standard deviations do not add linearly. R + R almost never equals R&R. 5. Accuracy is freedom from bias. If the long term average of your measurements equals the true value of the thing measured, your instrument is accurate, and in calibration. Precision is freedom from random error. It is expressed in terms of standard deviation. 6. This questions amounts to finding out how fast you can charge a 100pF capacitor through the parallel combination of two 360 ohm resistors. Two 360 ohm resistors in parallel are equivalent to 180 ohms. The appropriate formula for risetime is 2.2 x R x C. 39.6 nanoseconds. This is important, because it sets the limit on the fastest physical event you can see with that strain gauge arrangement. 7. Two identical strain gauges in series form a voltage divider. If both are subject to the same strain, there will be no change in voltage at their junction. Since the voltage at the junction of the multiplier resistors is also fixed, the correct answer is zero. | |||
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I don't know shit about horses, denton. | |||
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quote:Of the little I do know about horses, they do shit. ![[Smile]](images/icons/smile.gif){kind=icon} Turok | |||
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quote:Yes indeed, I figured my lack of response would ruffle your feathers. Rather than waste my time providing Technical answers which you would "attempt to disagree with", I'll just respond to the one "most pertinate" to the Thread. No real use trying to correct you when you don't know the difference between a "Set-Up Procedure" and "Calibration". ... As far as #5, I will correct the above which is just too laughable to ignore. And I'll try to simplify it so nearly anyone can understand it, plus give examples. Precision is "the degree of useable accuracy". And Accuracy means "measurements which are repeatable when compared to a Standard". Examples: In the previous Strain Gauge posts: quote:This implies the Strain Gauge "Accuracy" has a useable "Precision" in the Hundreds, Tens and Units levels. (AB,cde psi where the "cde" values would be precise.) Then when pressed about the Precision: quote:I left the entire quote intact, though the important part is (the reluctantly admitted), "250psi...error". I would suggest this value has a "Range" that exceeds this value, but I'll also admit my data concerning that knowledge is a bit dated and not worth the argument. So, now the Precision is no longer "three significant figures" which means the "cde" values are worthless. But, when the typical SGS user sees the numbers listed in the "cde" area, most are "mislead" into thinking the SGS has "more Precision" than it actually is capable of. ... Unless you understand "Accuracy" is a totally meaningless term unless it is repeatable when compared to a Standard, then you are wasting your time trying to grasp any of "the correct portions" of this thread. That is the crux of the central point Denton and I totally dieagree on. From my understanding of your posts, you are positive no "Standard" is required for Calibration. This is so wrong, it causes me to have to stop and question all other portions of your posts. A person can take "an infinite amount of observations" and unless some of those "observations" are in comparison with a "Repeatable Standard" to Calibrate the Accuracy, they are nothing but raw, questionable data of an unknown Accuracy level. An Example of verifying the Accuracy of a SGS would be similar to what Brent posted when he mentioned: quote:There was a considerable difference in the "SGS Pressure" (58,0K PSI compared to 48,9K PSI) while the Velocity was fairly close (2667fps compared to 2594fps). This "totally blasts out of the water": quote:Obviously from Brent's Data the "long term average" is complete and utter nonsense for determining accuracy in a SGS. In defense of those Manufacturers, it could be a multitude of things creating the difference, but it is interesting to see the Velocities so close. And, I still contend the SGS "can be Semi-Calibrated" with Factory Ammo, but even then the Data should be questioned just as Brent has done. Come to think of it, this also TOTALLY PROVES the very first post I made in this Thread(no gloat , just Brent's above facts ![[Wink]](images/icons/wink.gif){kind=icon} ):quote: quote:Best of luck to all you guys. | |||
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Hot Core, when you find yourself in a hole, quit digging. Info, the important thing about horses is that one end bites and the other end kicks and poops. The saddle goes in the middle, on top, with the rider facing forward. Mount from the left side, and retighten the saddle cinch after the first 1/4 mile. The good natured ones are fine companions. | |||
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quote:I can't recall the actor who said it (one of the many 007 Bond's?), but the best way I know to explain horses is that "Horses are dangerous at both ends, and uncomfortable in the middle." My girl friend strongly disagrees with that, but I think she's allot biased Turok [ 11-07-2003, 03:41: Message edited by: Turok ] | |||
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quote:The Auto Industry Advisory Group QS9000 manual on measurement system analysis, page 16, quoting ASTM D 3980-88. quote:Juran's Quality Control Handbook, 4th edition, p 18.63-64. Gee, Hot Core, if you hit water or oil while you're digging your hole, be sure to let us know. [ 11-07-2003, 04:33: Message edited by: denton ] | |||
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Hot Core, Those MV's I posted were actually pretty "far" from each other, and the lower PSI for the slower one falls nearly in line with this. Another words, if you increased charge weight to bring that MV up to match the other one, you'd find the PSI is nearly identical, a little lower possible. If you call those MV's "close" when they're that friggen far apart, it's strange you don't see the pressures as being "close" too. The two cartridges tested and referenced above used different powders. The pressure / charge weight graph for them also shows the SGK load is using slower powder, ball type verses the extruded used in the Scirocco load. It is strange that Federal would download those SGK's to that extent, very strange. I've never found much extreme spread in them, and they will even shoot .5 MOA at 300 yards in the rifle. The first group at 300 with it was 1.1"... Your 20 years experience with SGS isn't really too believable at this point, and maybe never will be. Talk is cheap, and you've not yet proven anything to me, except for your blatant inability to participate to the debate in a logical and reasonable way, or it's your unwillingness to do so... Either way, logic goes out the window and turns to emotion with you when you're confronted with things you can't answer or don't like being pointed out. Rather than waste my time providing Technical answers which you would "attempt to disagree with", I'll just respond to the one "most pertinate" to the Thread. 1.) Don't you expect others to answer "your" questions though? 2.) And you don't disagree with anyones answers either, do you? When you're loosing a logical debate, you switch gears and go emotional and or simply ignor any questions posed to you. On another note somewhat relative to the topic here: You can never be too carefull or double check enough. I was at the range yesterday with a bunch of cases I had prepped and primed at home so I could weigh out charges incrementally to work up a load at the range using the arbor press to seat just what I wanted to check at the time. I was using a cheap, but accurate Lyman beam scale I'd used for years before I got my RCBS digital I'm using at home. I set the scale up in the shack next to the bench, out of the wind and would run in and weigh, then seat the next bullet, then go fire it, go weigh another and on and on until I reached my max. I started at 90gr Retumbo with the 210 JLK in my 30/338 Lapua Imp and was working up in .5gr steps. 91gr went 52,0K PSI and 3018 fps 91.5 went 55,3K PSI and 3084 fps 92.0 went 69,1K PSI and 3291 fps??????????? At first I looked at the MV jump, then the plot on PressureTrace when I saw how friggin high it was. I was stunned! I found the shack with the scale in it was being shaken by the muzzle blast and the big weight on the scale had been bounching from the 90gr notch to the 95gr notch! Went I went back to weigh the next one the damn thing had just bounced to the next notch and was setting on 100gr! I missed seeing the first bounce to 95gr from 90 and that was a close enough call! If I wouldn't have spotted the big weight in the wrong notch and had actually loaded 102.5gr on the next one, well, you get the picture.... ![[Eek!]](images/icons/shocked.gif){kind=icon} After that, I checked it every time and found it bounced to the next 5gr notch 3 out of 5 times, and the little tenth grain weight moved 1-3 tenths as well. What an absolutely dangerous situation turned out to be! I usually use the scale on the floor board of the truck but figured the shack would save time if a slight breeze came up... Had I not been using the chrono and or the strain gage hooked up, I would probably never have questioned my scale setting and simply noted the "high" shot at 300yds, loaded the next one.... at 102.5 and fired it! I was really lucky! | |||
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The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Guns, Politics, Gunsmithing & Reloading Reloading Pressure and velocity vs manauls #2
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