i just got my AND Fx120i. Got it setup and was reading through the manual and realized the only check weights I have is what came with my chargemaster. What weights are you using to check/calibrate your scales? Do I need some certified weights (ohaus), or something like the Lyman weight set, or just use my rcbs weights?
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Scale calibration weights
- Thread starter Kbroad
- Start date
High end calibration weights are crazy expensive and not really needed for handloading. The important thing is to calibrate around the mass you'll be loading at, and to keep the cal weights clean. I handle them with tweezers and keep them in their box when not in use.
This is a reasonably priced kit that is plenty good enough:
https://www.coleparmer.com/i/troemn...t=true&ip=no&gclid=CKvZ5aqc3tQCFQlWDQodknIE2g
This is a reasonably priced kit that is plenty good enough:
https://www.coleparmer.com/i/troemn...t=true&ip=no&gclid=CKvZ5aqc3tQCFQlWDQodknIE2g
I use a 100g check weight with my AND. That is 100 grams, not grains. I use an ASTM2 weight and it cost around $50, but I am really anal. A single "grain" of powder weighs around 0.001 grams, so I wanted a weight with an error less than 0.001. The ASTM2 weight has an error of 0.0005 grams which fits the bill.
http://www.oldwillknottscales.com/ad...tm-2-100g.html
http://www.oldwillknottscales.com/ad...tm-2-100g.html
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That's exactly what I'm talking about. 100 grams is ~1500 grains. You'd be better off to calibrate in the 2 to 10 gram range, depending on what cartridge you are loading. See here:
http://www.balances.com/and/calibration.html
I thought it said right in the manual of fx120i to calibrate with a 50 or 100g weight, if you calibrate like you say with a 2-10g weight, would you not be altering the whole working of the scale?
The Fx120 requires that you use an external check weight, and it only accepts weights of 50g or 100g. This is straight out of the user's manual, page 26:
http://www.andweighing.co.uk/wp-cont...ls/fz_fx-i.pdf
As to your assertion that using a calibration weight that is much heavier than the typical charge weights used by handloaders somehow results in poor calibration for light measurements, well I would need to see some evidence of that. You are assuming that the scale has a non-linear response across its specified weight handling range - do you have any evidence to back that up? These are extremely expensive scientific scales, and they are designed to have a linear response across its weight handling range (0.001g to 122g).
Edit: The specified linearity of the Fx120 is +/- 0.002g, so the "problem" you are referencing simply doesn't exist. This type of performance is why we pay the premium for these scales.
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Haha, man are we in the weeds. None of this will make any difference when it comes to groups on target. Like most of my reloading habits, extremely accurate charge weight measurements are a way to keep my OCD demons in check.
For an FX-120 internal (software) calibration used for handloading, the 50g weight is better than the 100g, because 50g is closer to the charge weight. But then in routine use, you should use a cal weight as close as possible to your charge weight. If you load 338LM at ~90 grains, that's about 6 grams, so a 5 gram weight is a good reality check for linearity. I've taken calibration training from Mettler, Sartorius and Agilent and I currently am CPO ("owner") of about $200K of analytical balances. The "evidence" I have is from the examples given in every training class I've taken that show how balances age, and how the manual calibration protocols are implemented to achieve best linearity over time.
FYI, I use an FX-120 on my reloading bench and paid a bit over $500 - it's nice but in the big scheme of things, it's inexpensive. The lower end of expensive balances is on the order of $25K.
I use the 50G to calibrate. Remember we "reloaders" are not necessarily concerned if our 43gr of h4350 is the same as everyones 43gr of h4350. What we care about is that our scale reads what it thinks is 43gr of 4350 the same each and every time. Repeatability is the focus.
You have yet to offer any evidence for this statement. With a linearity of 0.002g, and assuming you calibrate on a regular basis, there is ZERO difference to a reloader between calibrating with 50g or 100g. Your statement suggests that calibrating with a weight that is much heavier than the charge weight imparts a bias on the lower end of the weight range. AND specifications bound that bias to no more than 0.002 grams over the entire weight handling range.
Any argument based on "how balances age" and "linearity over time" is moot if you simply calibrate on a regular basis. I calibrate every time I reload because it takes 10 seconds.
But as was previously stated, repeatability is what is important, not absolute fidelity. Another reason to calibrate regularly.
Agree that repeatability is the important issue... not pure calibration against reference standards.
To that end, grab yourself a stainless screw. Cut/file/dremmel it until it weight exactly your charge weight or a nearby whole grain increment. Keep it around and toss it in the reloading pan if you ever want to reassure yourself that the scale is staying consistent during a loading session.
I've got one at 25.00g for loading small BR based cases, one at 45.00g that I use when loading 308 based cases, and one at 60.00gr for loading long action rounds. Great peace of mind, no matter what kind of scale you're using.
To that end, grab yourself a stainless screw. Cut/file/dremmel it until it weight exactly your charge weight or a nearby whole grain increment. Keep it around and toss it in the reloading pan if you ever want to reassure yourself that the scale is staying consistent during a loading session.
I've got one at 25.00g for loading small BR based cases, one at 45.00g that I use when loading 308 based cases, and one at 60.00gr for loading long action rounds. Great peace of mind, no matter what kind of scale you're using.
Maybe you should have read the link I posted...
http://www.balances.com/and/calibration.html
The key quote being:
"Calibrating a balance closer to the user's actual maximum weighing capacity will offer a more accurate calibration."
So the balance manufacturer agrees with me...
Actually I did read the article. And I will grant you that in theory, it does make sense to use a check weight that is closer to your charge weight. However, I still stand by my statement that for the Fx120, it makes no difference whether you use a 50g or 100g weight. It all comes down to linearity.
In the article, they use the example of the EK-6000. This particular scale has a manufacturer linearity spec of 1 gram! That is three orders of magnitude (1000x) higher than the linearity of the Fx120. This means that your measurement can be off by as much as 15 grains, which of course is extremely dangerous for a reloader. So for this particular model, it is indeed important to calibrate with a weight close to your charge weight.
But this thread isn't about the EK-6000. We are talking about the Fx120, which has a linearity of 0.002g. That means that a calibrated scale is at most 0.002g off, regardless of whether you use a 50g or 100g check weight. Maybe the 50g weight will give a slightly smaller bias for standard charge weights, but the MAXIMUM possible bias is only 0.002g! That is roughly two granules of Retumbo powder.
Also, keep in mind that the average charge weight (let's say 40 grains) is still three orders of magnitude higher than the resolution of the scale. The bias will be the worst at the extreme ends of the weight range. Even a relatively light 40 grain weight is three orders of magnitude away from the extreme bottom end, thus it is reasonable to conclude that the actual bias in the 40 grain range is significantly less than 0.002g.
Bottom line, yes, you are right that a check weight closer to the charge weight is better. However, in practice, using the Fx120, the additional precision is completely useless since the bias is on the order of a single granule of powder.
Try making that argument with an ISO auditor when they ask for your linearity test data. In practice, spouting the specs of your FX120 doesn't get much traction.
Haha, if you want to disparage me for actually understanding how my equipment works rather than adhering to some random process for no reason, go right ahead. But the numbers don't lie; a 100g check weight is perfectly suitable for the task at hand.
If you are so convinced that it is necessary to calibrate with a weight close to your charge weight, regardless of the linearity specs of the scale, then buy a different scale. The Fx120 only accepts 50g or 100g. On a log scale (better for representing data that spans many orders of magnitude), 50g and 100g are essentially equidistant from your standard charge weight. Consider:
log10 of 40 grains = log10 of 2.59g = 0.41
log10 of 50g = 1.70
log10 of 100g = 2
log10 of 40 grains = log10 of 2.59g = 0.41
log10 of 50g = 1.70
log10 of 100g = 2
You are choosing to ignore the recommendation of the manufacturer of your balance. All they did was invent it, so go ahead and ignore them.
You are calling ISO's audit process for analytical balances "random". Sounds defensible, since all they do is set protocols that are followed globally.
Your soap box is overloaded. Keep preaching specs and ignoring how professionals do their work.
You are exactly right. I am willfully choosing to ignore their recommendations because I have carefully considered the impact of my decision and made the determination that the impact is negligible for my purpose. You still have not disputed that the impact is negligible; you just fall back to a straw man position that this is not how professionals calibrate.
Have you ever reduced your vehicle's tire pressure below the manufacturer's recommended level to increase traction on a dirt road? Well I have, and the world didn't end. Engineering is all about understanding your tools and applying them in a way that is consistent with their design limitations.
OP, choose a high quality 50g or 100g weight and don't give it a second thought. Calibrate regularly and your charge weights will never be the weak link in your reloading process.
I'm out.
Have you ever reduced your vehicle's tire pressure below the manufacturer's recommended level to increase traction on a dirt road? Well I have, and the world didn't end. Engineering is all about understanding your tools and applying them in a way that is consistent with their design limitations.
OP, choose a high quality 50g or 100g weight and don't give it a second thought. Calibrate regularly and your charge weights will never be the weak link in your reloading process.
I'm out.
Not really. Having acquired linearity data for over 3 decades and having watched how linearity degrades over time, I'm basing my comments on real world data. I'm talking cheapo balances like the FX120 on up through high end Mettlers. A new balance may be reasonably linear but degradation over time is common. That fucks up your consistency. Professionals check standards near the target mass to insure consistency. And - it's trivial to do as Sheldon detailed above.
I find this whole thread, while a little bit educational, to be quite hilarious. There is no way in hell that you can convince me that the level of accurate calibration being discussed makes one iota of difference in anyone's loading schema. With the scale in question having such a minute margin of error with respect to our typical loads and with the successful loader using a properly developed load that will shoot in the same place with even +/- 0.1 grains difference in load, the level of potential variation being discussed is orders of magnitude smaller than any amount that would make a bit of difference to your load.
Sure, those of you that love the purity of your process and want everything to be 100% perfect will continue to do so. But I hazard a guess that 95-99% of hand loaders do not hand load as a hobby. Most of them shoot as a hobby and hand load to support the hobby.
Triple, you should be having this argument on a scientific board where these things get really tense and everyone gets their panties all in a bunch over details that matter only to them and have zero bearing on so much else. So far, all you have argued successfully is that there are standards and they must not be digressed from or you will not be following the standards. Oh, and standards are obviously there for a reason. Valid point. That these arguments have little to no bearing on the accuracy of a person's hand-loaded rounds and the resulting accuracy of said rounds matters not to the pure argument. But when you choose to ignore the orders of magnitude involved in the results required vs. the capability of the equipment, the argument is so much fluff and hot air to the germane discussion.
Sure, those of you that love the purity of your process and want everything to be 100% perfect will continue to do so. But I hazard a guess that 95-99% of hand loaders do not hand load as a hobby. Most of them shoot as a hobby and hand load to support the hobby.
Triple, you should be having this argument on a scientific board where these things get really tense and everyone gets their panties all in a bunch over details that matter only to them and have zero bearing on so much else. So far, all you have argued successfully is that there are standards and they must not be digressed from or you will not be following the standards. Oh, and standards are obviously there for a reason. Valid point. That these arguments have little to no bearing on the accuracy of a person's hand-loaded rounds and the resulting accuracy of said rounds matters not to the pure argument. But when you choose to ignore the orders of magnitude involved in the results required vs. the capability of the equipment, the argument is so much fluff and hot air to the germane discussion.
LOL yep.
Here's three groups from shooting yesterday morning .... two are with powder weighed to the kernel. One was thrown on a Dillon progressive press. All have single digit SD. You tell me which is which...
LOL yep.
Here's three groups from shooting yesterday morning .... two are with powder weighed to the kernel. One was thrown on a Dillon progressive press. All have single digit SD. You tell me which is which...
Lower right is from the Dillon, I'm that smart.
The group on the right (#5) or the one that impacted lower right (#1)? Not that it really matters lol.
I caught these pics in bighorn action thread, lol
When I first saw the pic was going to mention poi change, let it go and then viewed bighorn one. lol
That's all fine and dandy, Lash, until you try to use your FX120 for a long time, like 10 or 15 years. Since I plunked down over $500 of my hard-earned bucks, I'd actually like it to last 20 years and that's not an unreasonable expectation. Go look at linearity data over that long of a use cycle. Linearity deviations are often unpredictable - the user never knows when they will happen. Tripling or quadrupling of a linearity spec is not uncommon. I recently saw 10X spec in a 5 year old $20K balance. 10x spec ain't fluff, nor hot air. Who knows, maybe one of the lab people abused it? They are one of the reasons labs hire techs to do the linearity adjustments. That's not at all the same thing as the typical user calibration process. Compared to lot-to-lot deviations in powder or primers, it certainly can get lost in the noise, but the goal is to strip away all the noise you can, right?
How hard is it to grind a stainless screw to size and toss it on every now and then?
Point taken. I do think that before I ground down a screw for each of the four different load ranges I load currently, I would just buy the set that Gary55 posted a link to on page one of this thread. $25 shipped for a full set of calibration weights to my door vs. hours of grinding, weighing, regrinding, etc to make those weights myself. In fact I did just that.
You probably have bullets that weigh 55.0gr, that make a perfect checkweight. I would never trust calibrating 20x heavier than actual use; I've seen just enough issues over the years. Also be aware that every time you calibrate anything, some degree of error is involved. Hence a checkweight for confirmation.
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Intersting discussion, and timely for me since I am sitting here waiting for the Fedex man right now, to take delivery today of this:
https://www.tequipment.net/Scientech/SA310/Scales-/-Weight/?Source=googleshopping&/?utm_content=scientech SA310&utm_term=&utm_campaign=Shopping Campaign(BSC)&utm_source=Bing_Yahoo&utm_medium=cpc
I bought it surplus, I didn't pay $2,000 for it.
https://www.tequipment.net/Scientech/SA310/Scales-/-Weight/?Source=googleshopping&/?utm_content=scientech SA310&utm_term=&utm_campaign=Shopping Campaign(BSC)&utm_source=Bing_Yahoo&utm_medium=cpc
I bought it surplus, I didn't pay $2,000 for it.
Interesting thread.
I calibrate with a 100 gram weight - because 100 and 200 gram weights are the only ones supported by the scale software. I use my powder pan as a check weight. It weighs the same plus or minus 1 milligram every time I use it - seems to me it is 9.212 or 9.213 grams. I don't recall exactly, I have it written down next to the scale. My 308 charge is 2.690 grams, I accept between 2.689 to 2.691. My 300 win mag charge is 4.406 grams, I accept 4.405 to 4.407. I have never seen the tare weight drift more than 1 milligram. 1 grain of IMR 4064 weighs between 1 and 1.5 milligrams. 1 grain of IMR 7828 weighs between 1.5 and 2 milligrams.
I believe that consistent powder charges have mostly eliminated vertical from my loads. When I see vertical I can usually point to shooter error - usually shouldering the gun or incorrect sight alignment. I don't have data - I didn't bother to keep it - but I am confident in my results. I only care about the theory in application - steel on target.
I calibrate with a 100 gram weight - because 100 and 200 gram weights are the only ones supported by the scale software. I use my powder pan as a check weight. It weighs the same plus or minus 1 milligram every time I use it - seems to me it is 9.212 or 9.213 grams. I don't recall exactly, I have it written down next to the scale. My 308 charge is 2.690 grams, I accept between 2.689 to 2.691. My 300 win mag charge is 4.406 grams, I accept 4.405 to 4.407. I have never seen the tare weight drift more than 1 milligram. 1 grain of IMR 4064 weighs between 1 and 1.5 milligrams. 1 grain of IMR 7828 weighs between 1.5 and 2 milligrams.
I believe that consistent powder charges have mostly eliminated vertical from my loads. When I see vertical I can usually point to shooter error - usually shouldering the gun or incorrect sight alignment. I don't have data - I didn't bother to keep it - but I am confident in my results. I only care about the theory in application - steel on target.
I recently obtained a set of check weights and find them pretty dang useful. I don’t know (or care) how accurate my check weights are because consistency is what I seek. Powder is dropped with a Chargemaster and with longer reloading sections (100-200 rounds), sometimes there is the distractions of phone calls, work projects, etc. and I’ll see a .1-.2gn drift in the scale. I’ve found dropping ~40gn of check weights into the empty powder tray every 25-50 rounds by gives me confidence the scale is maintaining the consistency I seek. Anything beyond that feels unnecessary for my application (PRS & hunting).
Exactly, the weights wont be that far off, .08 grains of error out of 100 grams due to my check weight being cheap and not exactly precise is still good enough for me. Its only wrong in exactly the same way each time if I compare it to an absolute standard. Its still the same each time vs itself.
- Sep 1, 2017
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https://ce-products.myshopify.com/collections/featured-products/products/100-gram-calibration-weight
Also we include a 100 gram weight when you purchase a FX-120i Autotrickler/Autothrower Combo
Also we include a 100 gram weight when you purchase a FX-120i Autotrickler/Autothrower Combo
You have this scale that can measure to a tenth of a milligram so you're gonna have to step up your whole process.
You're gonna need a tiny little ruler and a scalpel and a loupe to read it.
No sorry, not sufficient. You're gonna need a dial kernel clipper and a microscope.
Even better! You're gonna need a digital kernel clipper with a calibrated microscope, and a fully redundant UPS to power it. You're gonna have to buy a special container to store the clipped powder fragments.
You won't be able to afford bullets.
I'm not as smart as some of you guys but I do carry about $3000 of class F weights in my truck and use them every day for my work. The sizes I use vary from 50 grams to 10KG. If I was using a scale for reloading that used a 50 or 100 gram weight for calibration, I would want to use a smaller one, one close to my charge weight, to confirm that calibration.
D
