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Old 10-09-2012, 06:40   #51
SJ 40
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I came across this some time ago and found it informative on digital scales.
http://www.mnguntalk.com/viewtopic.php?f=12&t=34414
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Old 10-09-2012, 07:04   #52
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Quote:
Originally Posted by ADK_40GLKr View Post
I copied this from a conversion site:
0.001g = 0.0154323580gr

I copied this description of the Gemini 20 from an on line store:

"Get quality and accuracy with the Gemini-20 digital gram scale. The Gemini-20 is accurate to 0.001 grams.

So the scale is accurate to (rounding off) 0.02 grains
What that specific online store has done is taken Gemini's "resolution" claim from the Gemini manual, and directly equated that to "accuracy", which we've determined are not the same.

Manual (from Richard's link (Page 5):
http://www.americanweigh.com/pdf/man...-20_manual.pdf
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Old 10-09-2012, 07:51   #53
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Originally Posted by SJ 40 View Post
I came across this some time ago and found it informative on digital scales.
http://www.mnguntalk.com/viewtopic.php?f=12&t=34414
SJ 40
Well, that guy sure paints a grim picture. I'm certain that there is some correlation between this and the link(s) I posted - just not sure I'm smart enough to figure out what it is.

The scale addressed in this post is the Dillon and this same kind of conversion error isn't mentioned in the [my] former articles.
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Old 10-09-2012, 08:52   #54
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Quote:
Originally Posted by SJ 40 View Post
I came across this some time ago and found it informative on digital scales.
http://www.mnguntalk.com/viewtopic.php?f=12&t=34414
SJ 40

He made a very basic mistake in that post. The D-Terminator is measuring to .003 gram NOT .01 grams as he seems to think. Look at the response from CED below.

Quote:
“The current D-Terminator electronic scale is measuring in gram and then convert the reading to grain. The error due to unit conversation will be within +-0.05 grain (equal to 0.003 gram)

No matter how, the error due to unit conversion will always be there. It is just a matter of which unit measure is more important for the application. “

Respectfully, Charles Hardy - CED
You need to be real careful reading this internet crap.
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Old 10-09-2012, 08:57   #55
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Originally Posted by SARDG View Post
Well, that guy sure paints a grim picture. I'm certain that there is some correlation between this and the link(s) I posted - just not sure I'm smart enough to figure out what it is.

The scale addressed in this post is the Dillon and this same kind of conversion error isn't mentioned in the [my] former articles.

That is a very interesting article! It is WRONG, but it is interesting.

In the section "First response from me on Oct. 2, 2010:", there is a table that indicates that certain readings, in grains, aren't possible due to mathematical oddities related to rounding. For example, 4.7 grains should never show up on the scale. If the table is correct...

So, how is it that I can walk out to the garage, load up a trickler and dispense a 4.7 gr charge? In fact, I watched for missing increments on the way up to 4.7 and, except for the occasions where I was overexuberant in twisting the knob, every single reading appears.

There is certainly some technical basis for some of the author's ideas but the problem with 'facts' is that, sometimes, 'experiments' disprove them.

I think that when a reloader moves from a quality beam scale to a digital scale, they have accepted the 0.05 gr error. I know that my Chargemaster and my D'Terminator don't agree to 0.1 gr. If I set the Chargemaster to dispense 42.2 gr, I will, more often than not, get 42.1 gr on the D'Terminator. I figure there are two round off errors going on and I'm willing to accept the variance.

I use check weights in the range of interest. For a 42.2 gr charge, I use a 50.0 gr check weight. Both scales read EXACTLY 50.0 gr. That's great! But the engineer inside me also knows that I have no idea whether or not the check weight is anywhere near 50.0 gr. All I know is that three things tend to agree. They could all be wrong. But they would be wrong together!

Another thing I learned: Your measuring device needs to resolve 10 times better than the thing you want to measure. If you want to measure 0.1 gr, you need to be able to resolve 0.01 gr, accurately. Which means that none of our common reloading measurements are worth a darn - engineering wise.

But, darn, they seem to work anyway... Experiments...

Richard
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Last edited by F106 Fan; 10-09-2012 at 09:03..
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Old 10-09-2012, 09:00   #56
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I think if I was CED I I would sue him and make him get rid of that slander.
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Old 10-09-2012, 09:03   #57
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Originally Posted by F106 Fan View Post
In the section "First response from me on Oct. 2, 2010:", there is a table that indicates that certain readings, in grains, aren't possible due to mathematical oddities related to rounding. For example, 4.7 grains should never show up on the scale. If the table is correct...

So, how is it that I can walk out to the garage, load up a trickler and dispense a 4.7 gr charge? In fact, I watched for missing increments on the way up to 4.7 and, except for the occasions where I was overexuberant in twisting the knob, every single reading appears.

Richard
Because the article is wrong. The Scale measure to .003 grams which means it's accurate to .05 Grains (actually a little better) and then the scale rounds to .1 grains. So it has more resolution then it needs for it's given task. Not less as he falsely is asserting.
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Old 10-09-2012, 09:07   #58
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Don't be surprised if you see a correction in that website in the near future.
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Old 10-09-2012, 09:09   #59
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Originally Posted by Colorado4Wheel View Post
Because the article is wrong. The Scale measure to .003 grams which means it's accurate to .05 Grains (actually a little better) and then the scale rounds to .1 grains. So it has more resolution then it needs for it's given task. Not less as he falsely is asserting.
Exactly! As you pointed out, Internet stuff isn't always correct.

Richard
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Old 10-09-2012, 09:18   #60
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Quote:
Originally Posted by ADK_40GLKr View Post
I copied this from a conversion site:
0.001g = 0.0154323580gr

I copied this description of the Gemini 20 from an on line store:

"Get quality and accuracy with the Gemini-20 digital gram scale. The Gemini-20 is accurate to 0.001 grams.

So the scale is accurate to (rounding off) 0.02 grains
Yeah, so it says. Let's see, they are trying to sell you something and?????????
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Old 10-09-2012, 09:30   #61
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Originally Posted by Colorado4Wheel View Post
Because the article is wrong. The Scale measure to .003 grams which means it's accurate to .05 Grains (actually a little better) and then the scale rounds to .1 grains. So it has more resolution then it needs for it's given task. Not less as he falsely is asserting.
You would think that the author would at least try an experiment before writing something like that. I would be embarrassed to have my name on something that is so obviously, and provably, wrong.

Richard
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Old 10-09-2012, 09:37   #62
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Yeah, so it says. Let's see, they are trying to sell you something and?????????
Even if the scale does all it says, how could we prove it? Our check weights are accurate to, perhaps, 0.05 gr. I don't know that they are any better than that and there is nothing on the RCBS web site that gives even a hint about accuracy.

The only thing to do is test multiple weights over many readings and see how they correlate to the nominal value of the check weight.

It might be worth the time to do the experiments. Just to see...

Richard
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Old 10-09-2012, 09:47   #63
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A scale that has a readout to .02grains (or better) is kinda annoying in some ways. It drifts with the wind or any tiny movement of the table. Your seeing way more information then you need. Not that you can't ignore that stuff. But don't expect it to be super stable on your actual reloading bench. Of course it's just "noise" that can be ignored anyway.
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Old 10-09-2012, 09:55   #64
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Originally Posted by F106 Fan View Post
...The only thing to do is test multiple weights over many readings and see how they correlate to the nominal value of the check weight.

It might be worth the time to do the experiments. Just to see...

Richard
We all need to get together in the center of CONUS somewhere and bring all our respective scales and check-weights for experimental testing, perhaps in some bar somewhere. OR, just get together at some bar and drink ourselves silly and forget about all this, uh... stuff.

I find that burying my head in the sand is the best way to cope with these burning questions.

My head hurts!
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Old 10-09-2012, 10:38   #65
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I am an NRA certified instructor for metallic cartridge and shot shell reloading. When students push me on ways to go cheap, like dippers instead of scales, old cans of powder, used dies of questionable quality Etc. All to save money. I ask one question.

Right now, put a dollar amount on your eyes and fingers then tell me if that amount is higher than the amount you are saving by going cheap?
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Old 10-09-2012, 12:20   #66
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I am an NRA certified instructor for metallic cartridge and shot shell reloading. When students push me on ways to go cheap, like dippers instead of scales, old cans of powder, used dies of questionable quality Etc. All to save money. I ask one question.

Right now, put a dollar amount on your eyes and fingers then tell me if that amount is higher than the amount you are saving by going cheap?
It's exactly what I preach, I am also a NRA Inst. You want to go cheap, buy cheap dies & even cheap press, but spend your money on a good scale & measure. It may not matter much loading midrange load for the 223 or whatever rifle, but it can be huge in pistol loading w/ uberfast powders, where the diff between starting @ max is less than 0.5gr.
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Old 10-09-2012, 14:05   #67
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Just don't quote this "noob" as an authority. I'm tryin' to figure it all out without blowing myself up!
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Old 10-09-2012, 15:24   #68
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This guy says he compared the Gemini 20 using lab reference weights and a mg accurate certified scale. He said it did indeed meet the specifications listed.



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Old 10-09-2012, 16:45   #69
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Of course you could buy a $50 beam scale and not worry about it.
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Old 10-09-2012, 16:56   #70
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Originally Posted by dwhite53 View Post
Gotta get a scale. Should have this already.

I have a number of dippers for pet loads made from trimmed 9mm cases.

Always calibrated. Only re-calibrate with new lot of powder.

Never go out of adjustment.

First charge just as accurate as the last charge.

EASILY HOLD +/- 0.1 grain all day long. Even if using a Harrell measure you better use a scale on each charge if you need better repeatability.

All the Best,
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This. Dippers are very precise. They are slow, but they are precise. The dippers need to be calibrated though. The Lee dippers are calibrated already. If you use the loads listed in the chart, you are good to go. But, the loads are limited. It can be hard to get a powder and bullet that you want to work with the Lee dipper you have. For 40SW, the only Lee dipper you can really use is the 0.5cc.

Making dippers from cases is the best way to go. You can make them to throw any weight you want, but you need to use a scale to calibrate them. Hook up with a buddy who has a scale. Bring some pistol cases, 32ACP works well, a file, and your powder and data to his house and make up some dippers. Glue the cases to bamboo grill skewers for handles. You can use Popsicle sticks too, but trim the stick down where it attaches to the case so powder doesn't collect on it.

I use a fine sharpie to write on the handle what the dipper throws. "3.5 Red Dot". You might need to use a Popsicle stick so you can write big enough to see

Anybody who says dippers aren't precise doesn't have a proper understanding of the place that precision has in reloading.
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Old 10-09-2012, 17:22   #71
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This. Dippers are very precise. They are slow, but they are precise. The dippers need to be calibrated though. The Lee dippers ...

...Anybody who says dippers aren't precise doesn't have a proper understanding of the place that precision has in reloading.
I can appreciate yours and other's can-do attitude and the ability to make something useful (even accurate) out of scraps of cases and sticks with mundane tools no more complex than a file, and running to a friend's house and playing with scales and files all evening to make it happen - but if I had to make 1/10, nay... 1/100 that effort, just for the privilege of having a system that's capable of producing perhaps less than 1/100 of what I need, I most certainly wouldn't have taken up reloading.

As someone said earlier, and to me at least... these techniques are best left for the apocalypse. Perhaps we'll see this on future installments of "Revolution".

I think I am happy that I wasn't 'here' for the good old days.
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Old 10-09-2012, 17:24   #72
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It may NOT vary during that test. The website article I referenced above claims that circuits built into cheaper scales can mask inconsistent measurements. If a 10gr weight is placed on the scale and actually measures 10gr, the circuits will take subsequent readings within a 'range' (as an example, 9.8-10.2gr) and display them as 10gr. The author suggests "cleansing the palette" of the scale between test weights by weighing a much heavier or lighter weight in between test weights.

These algorithms are allegedly how low-cost scales can use resolution to mask inaccuracy and imprecision.
It seems irresponsible for a scale that people depend on for safety to mask inaccuracy, but it doesn't surprise me, I know for a fact that my cheap bathroom digital scale does this. I can weigh myself, get off the scale, pick up a 5# weight and get back on the scale. It will read the same weight. If I weigh myself, take a shower, and re-weigh, I find I can gain or loose 5# just from bathing. I guess the time in the shower allows the scale to reset.

At any rate, I have said many times I don't trust cheap digital scales. You have no idea what is going on inside them. They could read correctly 99 times out of 100 and how would you know which ones are wrong? People pride themselves on the precision of their digital scales when as you pointed out, what they are really looking at is how many significant figures are being displayed.

For $22.00, at least the Lee scale has to be correct.
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Old 10-09-2012, 17:31   #73
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Originally Posted by SARDG View Post
I can appreciate yours and other's can-do attitude and the ability to make something useful (even accurate) out of scraps of cases and sticks with mundane tools no more complex than a file, and running to a friend's house and playing with scales and files all evening to make it happen - but if I had to make 1/10, nay... 1/100 that effort, just for the privilege of having a system that's capable of producing perhaps less than 1/100 of what I need, I most certainly wouldn't have taken up reloading.

As someone said earlier, and to me at least... these techniques are best left for the apocalypse. Perhaps we'll see this on future installments of "Revolution".

I think I am happy that I wasn't 'here' for the good old days.
It's not a good ole days or eotwawki thing, it's a money thing. Some people don't want to spend $100.00 on a scale and measure, and they don't need to. If the OP lived near me I'd make him up a dipper in 10 minutes and he'd be good to go. There really is no need to have adjustability. Many people are looking to make a cheaper version of ball ammo. Sine Win, Rem, Tula etc don't give you any expectation of a particular load, whatever load you come up with is as good as theirs. My buddy has been loading for two years now with a dipper I made him. I told him use this dipper, Unique, and any 124 grain bullet and you are good to go. The dipper is above the starting load, but still a full grain below the max. He'd have to use a hammer to pack the dipper and get his gun to blow up.
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Old 10-09-2012, 17:48   #74
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Originally Posted by stak View Post
This guy says he compared the Gemini 20 using lab reference weights and a mg accurate certified scale. He said it did indeed meet the specifications listed.

Amazon.com: Ginkgo's review of American Weigh Gemini-20 Portable Milligra...
You do realize that anyone, including the manuf, can post a review on the product right?
Dippers are fine for their intended task, making ammo that goes bang. If you do not have an adjustable measuire of some kind, then you are limited. Some reloaders/shooters are fine being limited, most though are not. Change powders or bulelts, make a new dipper? Not me, I like options. An adjustable measure & good scale give you unlimted options.
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Last edited by fredj338; 10-09-2012 at 17:52..
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Old 10-09-2012, 19:48   #75
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As I mentioned earlier, you could "calibrate" a homemade dipper, but different lots of powders can have different densities.

Example: Just last weekend, I ran ran out of powder from one lot. I refilled the hopper after empty with a new lot of the same powder and did all the usual measures to settle it, etc. (I do not mix lots). The new lot threw 2 tenths heavier because it was more dense. 2/10 wasn't a too terribly big deal with the slower burning powder I was using, but it could be a big deal if using a fast burner. I weighed on the scale and "re-calibrated" the throw by turning it down to a smaller volume.

Last edited by Taterhead; 10-09-2012 at 19:50..
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