Check weights

[itchyTF]

I have a set from Denver Instruments that says class U. Anyone know what that means? Unknown?

 

[Rocketvapor]

Class U (Ultra Class) is a little better than ASTM Class 1.
If they are in really good shape, no dents, dings, scratches, but out of cal date it would still be safe to ASSUME they would meet a lesser class for home use
Use the ASTM Class 2 spec for old out of date Ultra Class weights.
Maybe Class 4 specs for any aluminum mg weights.

Most "SETS" have combinations that can be inter-compared to find a single bad weight.

If you didn't buy them NEW watch for any weight that does not LOOK like the rest.

 

[itchyTF]

The set’s label shows 50g-1g but it also has a 100g which looks like the rest except the lifting stem is threaded so it can be removed to close the cover.
No aluminum.
I didn’t buy them new.
If I’m reading your chart right even class 2 is “good enough”.
The innerds -

 

[Rocketvapor]

The 100 gram is a substitute (doesn't fit) the lifting stem has a cavity for "Calibration Adjustment".
The set was probably sold with the 100 gram hole EMPTY, and labelled up to 50 grams.

Compare the 50, 20, 20, 10 to the 100 with your BEST scale.
They aren't in pristine shape but should be mo than good enough for reloading
Inter-compare to find any one of them way off.

 

[Straightshooter1]

Class U (Ultra Class) is a little better than ASTM Class 1.
If they are in really good shape, no dents, dings, scratches, but out of cal date it would still be safe to ASSUME they would meet a lesser class for home use
Use the ASTM Class 2 spec for old out of date Ultra Class weights.
Maybe Class 4 specs for any aluminum mg weights.

Most "SETS" have combinations that can be inter-compared to find a single bad weight.

If you didn't buy them NEW watch for any weight that does not LOOK like the rest.

Question: For measuring powder loads, does it really matter that a scale is really that accurate as long as it's being consistent . . . like the way we use comparators?

 

[itchyTF]

My best (and only) scale is the FX-120i. About a 5 min warmup and can’t remember when I calibrated it last.
The 100 = 100.002 and the 50, 20, 20 & 10 together was the same.

 

[Rocketvapor]

Consistentcy, the property of "Sameness over time" matters.
A bullet, a nickle, a Chinese cold rolled chrome plated weight will work as long as you don't lose or damage it.
For the OP and the U class weights, had they been in pristine condition, would have been good for another 20/30 years, but at a lesser class.
With wear, damage, corrosion, dirt, scratches, a little suspect.
The 100 gram has NO credibility until compared to the others.
The cavity could of had several milligrams of cal stuff in it.

Do a multi-comparison, SEVERAL swaps. Worn weights (clean) will seldom be heavy so you should be OK.
If the best you have is the FX120, then compare more than once.

Here is my Ultra Class Set.

NEVER handle them without gloves or tweezers or the shiny will leak out

 

[Webster]

Question: For measuring powder loads, does it really matter that a scale is really that accurate as long as it's being consistent . . . like the way we use comparators?

Your correct. You don't need a precise standard. If your 25 gram weight always measures the same wt. every time you put it on the scale everything is OK. If you weigh and put 35 gr of powder in a case and it's actually 35.17 it doesn't matter. All that matters is that it's always in error by the same amount every time. I made a stainless steel weight out of sheet metal and weighed it out to 4 decimals. I rounded wt. to 1 place and engraved 33.3 grains on my standard. I use it as a check wt. before any loading session. I don't care if my scale is 100% correct. All I need is for it to give the same amount of powder the same wt. every time on my scale. I'm using a beam scale. My scale would have to be damaged to give a bad reading. Not out of zero. I am not familiar how you zero an electronic balance. Is it done by pressing a zero button or somehow with a standard wt.? It's been 10 years since I occasionally used an electronic balance at work.



Side note.
Spell checking before posting only takes about 15 seconds.
1. I type my post in the reply area into word first.
2. If the text is in the reply area. Paint the text with the mouse. Hit control V to put it in memory > Control X to delete it from the reply area.
3. Open WORD paste in WORD by Control V. You can add or delet sentences if needed.
4. Ck Review
5. CK Spelling & Grammar
6. RT side of screen do needed corrections.
7 Paint the corrected text with the mouse
8 Control C to copy to memory
9 Close word , don't save
10 Go back to Accurate Shooting and paste the corrected text in the reply areas by hitting Control V.
Sounds complicated after a few tries you learn to do it real fast.
Word doesn’t catch all errors.

 

[JFrank]

I ordered a F1 check weight from Cambridge to go with my FX 120, they sent me the M1 instead so I figured WTH they know what they’re doing so I just use it no big deal, I also handle my weights with no gloves just clean fingers and occasionally clean the weights with eye glass wipes.
I hasn’t held me back from making great ammunition.

 

[Rocketvapor]

Did they charge you for an F1 ?
What weight value did you get as a check weight?
Your FX120 is probably better than your M1 check weight.

 

[JFrank]

Yeah maybe so, it’s a 100 gram to calibrate but when compared to other F1 weights it seems to be accurate enough. I also have a pair of 20 grain weights I find very handy at just the right weight range for my loading.
I’m not mixing uranium or splitting atoms, just weighing extruded powder to one kernel.

 

[chop house]

I’m not mixing uranium or splitting atoms,

Shhhhhhh...

 

[danny]

Class U (Ultra Class) is a little better than ASTM Class 1.
If they are in really good shape, no dents, dings, scratches, but out of cal date it would still be safe to ASSUME they would meet a lesser class for home use
Use the ASTM Class 2 spec for old out of date Ultra Class weights.
Maybe Class 4 specs for any aluminum mg weights.

Most "SETS" have combinations that can be inter-compared to find a single bad weight.

If you didn't buy them NEW watch for any weight that does not LOOK like the rest.

What would be the proper class of weights if you wanted to do a critical inspection of your scales, beyond just having something reasonable to keep an eye on your scales?

Danny

 

[Rocketvapor]

A few kernels of Varget is what most use

 

[Evan]

I have two 20gn and one 10gn weights. I check: 0, 20,40,50,30,10, 0. If it hits each spot on, the scale is in good shape for reloading work having demonstrated linearity and limited hysteresis across the range I use. There are cheap scales that fail this simple test.

I don’t recall the class of the weights. I lost the slip they came with.

 

[jelenko]

RCBS sells a set of check weights down to 1 gr.
For what we do, it's more about consistency than precision to a standard.

 

[Rocketvapor]

@Evan
A sensitivity test (very small increment) is the only thing missing from your test.
Your scale can settle on large increments (10, 20 30grains) but not be sensitive enough to FEEL that single kernel of Varget trickled in. ( )

An example of a accurate, stable, and linear scale, 300grams full scale with milligram resolution. Even though it has milligram resolution, just isn't sensitive enough to trickle.
Ten 10 gram test weights plus 1 gram (500mg+300mg+200mg).
A proper sensitivity weight at this load would be to add 10 milligrams, or less.
Would a single kernel of Varget demonstrate sensitivity at the 10 GRAM STEPS?

 

[Rocketvapor]

I know many folks rely on Check Weight "Sameness" and not absolute Accuracy relative to an accurately known "Weight".
If your beam scale has performed on the target for the past 20 years, how have your check weights performed? How do you determine your special calibration bullet is still 55.0 gr?

If you lost your Calibration Bullet, now what?

I've been an advocate of accuracy in addition to consistency.
Here's a post I made a few months back (this check weight thang comes up often)

Which Scale Check Weights?

Ahh Jim, the old scale in the picture would more properly be called a balance, it doesn't weigh anything. You need to zero it using a known mass. This particular one was made by Pacific, and at a total guess, probably dates from the 1950's. It's not damped in any way and just so simple there's...

forum.accurateshooter.com

 

[Webster]

I know many folks rely on Check Weight "Sameness" and not absolute Accuracy relative to an accurately known "Weight".
If your beam scale has performed on the target for the past 20 years, how have your check weights performed? How do you determine your special calibration bullet is still 55.0 gr?

If you lost your Calibration Bullet, now what?

I've been an advocate of accuracy in addition to consistency.
Here's a post I made a few months back (this check weight thang comes up often)

Which Scale Check Weights?

Ahh Jim, the old scale in the picture would more properly be called a balance, it doesn't weigh anything. You need to zero it using a known mass. This particular one was made by Pacific, and at a total guess, probably dates from the 1950's. It's not damped in any way and just so simple there's...

forum.accurateshooter.com

Nice explanation of wt. standard classifications and when each class is normally required. Looks like NIST replaced letter codes on standards with an ASTM designation. Looks like NIST/ASTM standards are in grams not grains?

What are Calibration Weight Classes?

One of the most common questions we get related to calibrating scales is "what calibration weight do I need?" There is much to unpack with this question and varies greatly depending on the user's application. Most people know how much weight is required to properly calibrate their scale, but...

www.scalesplus.com

I am not a competitive shooter trying to shoot groups in the 1's or low 2's. I don't really care if my scale is off by 1 kernal of powder. I am happy if I can shoot .350" groups with good bullets. If I lose my home made standard which I have had for 20 years, i'll just deal with it. How can I lose my standard if it never leaves the loading bench.


One gram is thus approximately equivalent to 15.43236 grains.

 

[Rocketvapor]

"Nice explanation of wt. classifications and when each class is normally required."

What they don't cover is what weight values are needed to confirm Full Scale versus small test weights, or sensitivity tests. The NIST document reference does.

I'll point out some logic errors many folks make.
Full Scale Calibration Vs a Full Scale CHECK.
A full check without invoking Cal can confirm your scale is still "In Cal"
Doing a Calibration, resets scale factor, and you lose a stability data point.
Most scales will always read the Cal Weight if you Re-CAL.

What accuracy @ Full Scale matters?
Cal with a 100.0001 gram weight,
Now RE-CAL with a 100.0101 weight (add 10 milligrams)
The scale measurement SLOPE will have changed by 0.01 PERCENT.
With a GOOD ZERO that 0.01 percent slope change will make most readings LOW.
50 grains will now read 49.995 grains
About one count on my EJ-54D2 on low range.

Linearity errors, usually a limit of design are usually stable (relative to overall scale stability). Some scales use software and linearity check weights to correct most of this error. It's weights at the low end of most scales that matter to us.
A 1,2,2,5,10 Gram Set would give the ability to check every gram from 1 to 20.

A sensitivity weight also doesn't need to be super accurate, just small enough (one or two counts) to prove the scale can detect that magical "One Kernel of Varget".

IF mo better scale accuracy isn't in your stars, then none of this really matters.