THR myth confirmation/busting - digital scale accuracy

[rcmodel]

Only problem I see with that is:
There is paper, and there is paper.

And there is humidity which changes the weight of the paper you use.

Same with using U.S. Coins.

There are silver old dimes, composite new dimes, and there are used dimes of all types.
And new dimes that wasn't exactly right in the first place.

The only check system you can actually trust are scale check weights, untouched by human hands.

rc

 

[LiveLife]

OK, rcmodel says we need more data.

Those with .015 - .02 gr resolution scales, could you please weigh various type papers cut into 1/4"x1/4" pieces and let us know how much they weigh?

Let's say, newspaper, copy/printer paper, post-it notes, etc.

Thanks!

 

[jcwit]

Being as I've never used 1/4" paper squares for reloading powder and as how my $40 dollar scale has always repeated accurately as ever I'll continue to use it to check the weight of my powder drops from my Lee Perfect Powder Measure.

 

[JerkandFlinch]

Use dollar bills they should be relatively consistent.

 

[LiveLife]

OK, anyone willing to sacrifice a corner of $1 bill for a good cause?

 

[rcmodel]

Use $100 dollar bills.
They should be 100 times more consistent then $1 dollar bills.

But that still doesn't address the humidity in them.

Is this boob money? sock money? or money that's been laying in the sun in Death Valley for a day?

It's a noble quest you are on BDS.
But there just isn't any common scale check weight that weighs exactly the same everywhere, when relative humidity is at work on paper everywhere, and can be weighed too.

Except metal scale check weights, which are not subject to humidity changes.

rc

 

[Reloadron]

I agree with RC. I believe the majority of digital scales marketed today and aimed at the hand loader are adequate for intended application. I also believe the majority of assorted check weights out there for the hand loader meet or exceed their uncertainty for their intended applications as to the hand loader.

With that said I do not see the use of 1/4" square cut pieces of paper being of much value for several reasons. There are, in my opinion too many variables at play including not really knowing what the weight of a single square cut is. Compound that with as RC mentions, there is paper, and paper and paper. The weight of the paper will change I would venture with any changes in relative humidity. How well can we control the environment surrounding the paper? I just don't see paper as a form of reliable transfer weight standard. Just my opinion.

Good check weights are inexpensive enough so given a choice I would feel comfortable with an inexpensive digital scale having a 0.1 grain resolution and +/- 0.1 grain uncertainty. All things considered I see no reason for the hand loader to shy away from digital scales to include the less expensive models available.

Ron

 

[RedHawk357Mag]

Duncan, OK, U.S.*
Now*
Current Conditions: Sunny*
Temperature: 99°F*
Feels like: 99°F*
Chance of precipitation: 5%*
Pressure: 28.78 inHg*
Sea level pressure: 29.79 inHg*
Humidity: 21%*
UV(UV Index),0..15:: 0*
Wind: 17 mph,S, Moderate breeze*
Weather station: Wichita Falls, Sheppard Air Force Base*
Measured: 31 minute(s) ago*
Weather forecast provider: Foreca.com*
no geomagnetic storm,Kp-index:: 2*

Detected (1) 1/4" by 1/4" copy paper. Paid 239.00 for the scale. Smallest Lyman check weight .5 gr. The paper weighed, .04 grs. The check weight weighed, .5 grs. The paper and check weight weighed, .56 grs. Scale is Accurate Vicon VIC123.

 

[cfullgraf]

But that still doesn't address the humidity in them.

In the paper industry, paper is measured "bone dry" to eliminate the effects of humidity. The paper is dried in an oven before weighing.

For folks education, the weight of paper, say 20 pound copier paper, is the weight of a ream of paper. That varies by the type of paper, in the tissue industry the ream size we used was 2880 square inches. There are several other ream sizes depending on the type of paper.

 

[LiveLife]

The paper weighed, .04 grs. The check weight weighed, .5 grs. The paper and check weight weighed, .56 grs.

So when the .04 gr piece of paper was weighed with the .5 gr check weight, it essentially showed .06 gr for paper weight.

Interesting.

Is that the result of scale resolution in effect?

VIC123 has .001 gram (.015 grain) resolution ... right?

 

[Reloadron]

So when the .04 gr piece of paper was weighed with the .5 gr check weight, it essentially showed .06 gr for paper weight.

Interesting.

Is that the result of scale resolution in effect?

VIC123 has .001 gram (.015 grain) resolution ... right?

Yes, that would be the scale resolution in effect. While the Acculab VIC 123 no longer exist it was replaced by the Sartorius AY123 Milligram Scale which is from my read the same scale in a different package.

When the scale is setup to display grains:

Capacity x Readability (grains)

1852.70 gn x 0.02 gn

So the least significant digit will be a 0, 2, 4, 6 or an 8. That is what is readable or what the scale is capable of resolving. So anything above for example 0.015 will be displayed as a 0.02. Anything below a 0.014 will be displayed as 0.00. That is my take on it anyway.

Ron

 

[kelbro]

If your question is whether or not it is 'safe' to use a cheap digital, you will not know until 'unsafe' occurs so if you want to use one, go ahead.

Been in the electronics industry for the past 30 yrs. I will use my 1010 thank you very much!

 

[LiveLife]

OK, that's what I have been hearing all these years (hence the reason for this thread). But since you worked in the "industry" could you elaborate why?

I am thinking, like Harbor Freight digital calipers which work fine, perhaps electronic circuits have improved to the point where even cheaper scales are more accurate/consistent now? Based on the data posted, Gemini-20 seems to be the Harbor Freight digital caliper of cheaper digital scales with .02 gr resolution and detected a single piece of paper.

BTW, I currently use two Ohaus 10-10 and FA DS-750.

 

[LiveLife]

So for those with greater than .1 gr resolution scales, could you weigh different paper types and see what the weights are?

I am thinking newspaper/post-it notes should be fairly consistent along with 20 lb copy/printer paper.

 

[X-Rap]

So what is to be determined from this paper cutting exercise that test weights can't ascertain?
If I find one of my scales be it beam or digital won't repeat measurements then I will repair it or toss it.

 

[LiveLife]

since rcmodel pointed out the potential for variations in paper weight, I am trying to get a consensus as which paper types (newspaper/post-it notes) are more consistent for testing scale sensitivity and consistency.

The OP premise was to confirm or bust the myth of digital scales not being accurate or consistent. I think that myth has been busted.

Now I am expanding on the OP premise to determine which digital scales are more accurate/consistent and the method to determine - which check weights cannot do as the smallest weight is typically .5 gr whereas 1/4"x1/4" piece of paper is .04-.06 gr to better test sensitivity and consistency.

I figure newspaper and post-it notes are fairly common and maybe consistent enough to use as a reference since 20 lb copy/printer paper may not be available to everyone.

 

[GaryL]

You need something that is consistent across the board. Coins might work if you pick recent, near mint condition, with same year and mint. Might be able to establish a typical distribution and see how it plays out.

The problem with anything household is the wide variance in anything manufactured in different places with different processes and material differences.

You also have to consider that a 1/4" cut square is going to vary from one person to the next, even from the same material. A larger piece should have a smaller variance percentage wise, assuming the same cut tolerances.

You could try a 1" square of 4mil plastic, but it should come from the same plant, and even then its going to have some variance.

 

[LiveLife]

Coins are not needed when we have check weights.

The reason why we are using 1/4"x1/4" pieces of paper is because the smallest check weights are typically .5 grain.

We are trying to verify detection below .1 gr which .5 gr check weights cannot do.

 

[RedHawk357Mag]

Dog gone auto correct. Scale is indeed A ACCULAB VIC 123. My take on the combined weight fluctuations is paper is just over .04 but not enough to push to .06. With the combined check weight and paper pushed it to the next even hundreds. Will say I love this scale. My back up is a couple of USA 1010s. But vision and garage lighting just makes the 123 much nicer to use.

 

[Jesse Heywood]

Guess I am going to throw a fly in the ointment. RCBS Range Master 750, new in 2009. The only test weights that I have are the 20g and 30g included for calibration. Temp in the house us 73*F. Humdiditty unknown. I cut 10 squares of 20 lb copy paper. All measurements were taken using the pan.

First, zeroed on the empty pan. Added paper individualy. Reading was 0.0 grain on all.
Next I tried adding all ten at once. Still read 0.0.

Time for another plan. I found some aluminum washers (aircraft) that were required to be precision made for my previous employer. Think of how many fasteners are used in a 747 with the need to determine the weight of the total.
The washers .0016 thick, inner diameter .263, outer .500. Checking a sample, the weight was 1.5 grains. These were consistenty 1.5, 3.0, 4.5, 6.0, 7.5, 9.0, 10.5, 12.0, 13.5, 15.0 grains.

Next I ran the paper again with one washer. 1.5, 1.6, 1.6, 1.7, 1.7, 1.8, 1.8, 1.9, 1.9, 2.0. Obviously my squares weighed .05 grain each.

 

[Stev32k]

This is a subject that is near and dear to my heart. I bought this digital scale http://www.amazon.com/gp/product/B003STEJD4/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1 in October, 2012. I also have a set of ASTM certified calibration weights.

I checked out the scale when I first received it in 2012 and several times since. It has been amazingly accurate and repeatable. Here are test results from 2012 and 2014.

 

[LiveLife]

Next I ran the paper again with one washer. 1.5, 1.6, 1.6, 1.7, 1.7, 1.8, 1.8, 1.9, 1.9, 2.0. Obviously my squares weighed .5 grain each.

That seems to be the case. And you meant .05 gr?

First, zeroed on the empty pan. Added paper individualy. Reading was 0.0 grain on all.
Next I tried adding all ten at once. Still read 0.0.

Now that is odd.

 

[jcwit]

What does all this accomplish in regards to reloading?

Even the Bench Rest crowd mostly throw their charges with measures.

 

[Stev32k]

What does all this accomplish in regards to reloading?

Even the Bench Rest crowd mostly throw their charges with measures.

It only matters if you want to really know what you are doing. When I first started reloading I didn't have a scale or a press. I used a Lee dipper and a small hammer and I shot prairie dogs and coyotes at 300+ yds with my reloads. My hit percentage was not that great, but I still got more than a few.

Now I shoot bench rest and accurate powder weights are important. If you don't care if your groups look like a shotgun pattern then you don't need a scale.

 

[jcwit]

It only matters if you want to really know what you are doing. When I first started reloading I didn't have a scale or a press. I used a Lee dipper and a small hammer and I shot prairie dogs and coyotes at 300+ yds with my reloads. My hit percentage was not that great, but I still got more than a few.

Now I shoot bench rest and accurate powder weights are important. If you don't care if your groups look like a shotgun pattern then you don't need a scale.

Well I must be someone who has no idea what I'm doing but I'm able to shoot one hole groups at 100 yds. In fact I am able to keep my reloads at .089 CTC groups of 5 rounds. This is off the bench of course, .223, Sierra 53 gr. HP Match, 22 grains of Accurate 2015 thrown by a Lee Perfect Powder Measure, cases? Lake City all 5 marked 01.

Dam, its something to be such an idiot and not having any idea what I'm doing as you seem to imply.

How many years of experience have you got Steve?



Only groups I shoot that resembles shotgun patterns are my handgun shooting. And it has nothing to do with my reloads, handguns, its all because of me and my shaking, started at the age of 65 and has gone downhill for the last 5 years.