In Praise Of Gravity/Beam Scales

[M-61]

A well Tuned Beam Scale works with your cell phone in the room ?
You don't need a Line Controller or LED Lights or electricity !!

That $ 1,750.00 Buys Powder and Bullets

I will admit I have all that Stuff Plus !!! I sometimes Wonder ????

I made Distinguished Riflemen State Top 10 and High Master Long Range all with a RCBS 304 ( It gave up after 25 years ).
Then the Trip Down Rabbit Hole Began .. $$$$$$$$$$

Just wondering what “gave up” on the 304 scale
Mine is older than yours and I’ve not had any problems, and it is in use, not sitting in a box for years. I am careful with it and it sits on an elevated stand so aside from viewing it head on it doesn’t get ‘ bumped’.

 

[M-61]

Oh, I'm just being a pedantic jerk, but in good fun, for sure.

That said, what we currently define as "Earth's gravity" does indeed vary quite a lot in magnitude over time, and by location at any given moment. The easiest to explain is elevation. Higher ya go, the lower gravity is (as a general statement). If you weigh a sample to be 100.00xx grams in Denver, CO, it can be show to be OVER 100.00xx grams in someplace like Death Valley.

The magnetic poles are in continuous movement, and require us to constantly re-orient hard copy maps and I'm sure geo-oriented software and aerial hardware as well.

Earth's magnetic field also completely changes polarity in what seem to be fairly "random" intervals from 8,000 years to tens of millions, at times. Very easily seen in oceanic basalt records, if you know how to look, and do a little math.

And before anybody asks, no, geology is not contrary to the "God narrative", unless somebody chooses to make it so.


Not in a way measurable by us.


Have a nice night, y'all!

Interesting reply. However I see no real relationship between gravity and the magnetic poles.
There indeed is a fractional difference in gravity say reloading on Everest and on a raft on the Dead Sea.
Far different and way more important and very variable is the earth’s magnetic field.
Look at a compass rose on a chart. They give you the minus or plus to make the appropriate adjustments for EACH year from when the chart was printed. And there are NO decimals involved. It’s a full degree each year for five years. The field shifts in five year cycles.
I’m going off subject here so I’ll end with what is my second sentence.

‘Dead men can’t vote twice’. DMCVT

 

[Rocketvapor]

What in the world does the Earth's magnetic field have to do with scale calibration or drift?
Navigating with a compass and charts, maybe. Navigating with Gps? Nope.
LOCAL GRAVITY probably won't matter on a 100yd target but likely will at 1000yds if a digital scale is not calibrated at the using location.

Factors that impact PRECISION measurements in the lab such as buoyancy of the test article compared to the buoyancy of the calibration standard also won't impact reloading measurements.
Years back the reference for calibration weights was changed from Apparent Mass Vs Brass (8.4g/cc) to Apparent Mass Vs Stainless steel (8.0g/cc). That required a mathematical correction to be applied to ALL the old base standards to the new base of about 8ppm (0.0008 %) just due to differences in buoyancy in air.

Before high precision digital balances, two pan balances were used for high precision mass comparisons.
A mass was placed in each pan and the balance allowed to swing. To compensate for variations in friction swinging in one direction Vs the other, a pointer and scale was used to record the 'Turning Point' of the pointer for at least 3 consecutive turning points. The average recorded.
Then the two were swapped and the swinging was repeated. This eliminated beam arm ratio errors. Swapped and swung again. S.D was calculated from the averages of the turning points.
To validate, a small sensitivity weight was added to one pan and the swing recalculated.
At the 1 Kilogram level our lab demonstrated the ability to compare to a fraction of a mg.
From memory I believe the NBS measured difference was 0.6 mg (0.6 ppm).


So far, no one has responded to the questions I asked in a previous post;
Would a beam scale read correct on the moon? Why? or Why not?

 

[Adam in WI]

.So far, no one has responded to the questions I asked in a previous post;
Would a beam scale read correct on the moon? Why? or Why not?

My guess is yes. Although the weight of your charge is lower than on earth, the force required to move the beam has also been reduced by the same amount.

 

[M-61]

What in the world does the Earth's magnetic field have to do with scale calibration or drift?
Navigating with a compass and charts, maybe. Navigating with Gps? Nope.
LOCAL GRAVITY probably won't matter on a 100yd target but likely will at 1000yds if a digital scale is not calibrated at the using location.

Factors that impact PRECISION measurements in the lab such as buoyancy of the test article compared to the buoyancy of the calibration standard also won't impact reloading measurements.
Years back the reference for calibration weights was changed from Apparent Mass Vs Brass (8.4g/cc) to Apparent Mass Vs Stainless steel (8.0g/cc). That required a mathematical correction to be applied to ALL the old base standards to the new base of about 8ppm (0.0008 %) just due to differences in buoyancy in air.

Before high precision digital balances, two pan balances were used for high precision mass comparisons.
A mass was placed in each pan and the balance allowed to swing. To compensate for variations in friction swinging in one direction Vs the other, a pointer and scale was used to record the 'Turning Point' of the pointer for at least 3 consecutive turning points. The average recorded.
Then the two were swapped and the swinging was repeated. This eliminated beam arm ratio errors. Swapped and swung again. S.D was calculated from the averages of the turning points.
To validate, a small sensitivity weight was added to one pan and the swing recalculated.


So far, no one has responded to the questions I asked in a previous post;
Would a beam scale read correct on the moon? Why? or Why not?

Since you didn’t quote or refer to me I’ll surmise your first sentence was in agreement with mine
and I just continued with an explanation ( brief) on nav and etc.
The rest I don’t have a clue.
But unlike others who ask a question and when it’s answered don’t bother to reply I won’t be that rude thus: I’d say the scale will not read the same due to a lesser gravitational pull on the moon.
No clue if I’m correct but it sounds good to me

 

[Rocketvapor]

@ adam Good answer, sort of.
Frictional errors would be less with the force on the knife edges being less.
What is the powder charge being compared to with a reloading beam scale?
Would it be the mass of the counterpoise times the distance from the knife edge, compared to the mass in the pan times the distance from the knife edge? You, your rifle, your ammo might WEIGH less on the moon but will have the same MASS.

Sensitivity (one kernel) might be reduced as the force of the Moon's gravity to move the pointer off zero is much less.

 

[CharlieNC]

Gravity and magnetic poles not withstanding, all I care about is the tuned Redding I purchased from Scott years ago provides +/- 0.05gr based upon weighing on an electronic at my home base.

 

[Rocketvapor]

I don't know what Scott does to Tune his scales but I do know what we did in the cal lab at the Rocket Factory.
Most we had were in grams not grains.
The biggest issue we had was damage to pivots as the scales were transported, usually with the beams on the pivots. We had bags of agates and knife edges. Another was contamination of the counterpoise changing it's 'Weight'.
Check standards several times better than the scale accuracy were used to check accuracy and sensitivity at several loads over the measuring range. Sometimes we tried to save a scale by repairing a damaged notch.
After obtaining a good zero 5 to 10 points over the range were checked with mass standards of adequate accuracy. A sensitivity test was performed at both low load and full scale. Range extending counterpoise weights were checked at full scale.

A +/- 0.05 grain accuracy (sensitivity) at a load of 100 grains is +/- 0.05%
At a load of 24 grains that is +/- 0.2%
At full scale of 500 grains that +/- 0.05 grains is +/- 0.01 %

Other than the labor to clean and certify performance, having all the necessary calibration standards is an expense most individuals won't take.

 

[natdscott]

I'm so glad I posted what I did.

 

[Clancy]

I bought the fx120i and autotrickler in 2019 and sold it in 48 hours. I think the autotrickler portion was absolutely wonderful, but a $1200 setup that requires a $100 check weight and works best with a few hundred dollars more in accessories just wasn’t for me. If I ever need more precision again, I’ll buy a Parker tuned beam scale.

I don’t fault or question anyone for buying and using any scale that meets their needs and makes them happy though.

 

[Rusty2]

DLT, I get it, truly I do. Many people have waited for far too long. I do not blame you for not sending your scales to me. In fact, I had no idea you were contemplating it. But now that I know, I can work on living with the sorrow of having the knowledge that you were perhaps contemplating having me work on your scales but decided against it.

That said. I’m at a place now where I can tell a customer when to ship a scale to me and get it turned around in a week. So, DLT, should you decide to risk it all and inquire about potentially getting one or another of your scales tuned and calibrated, I assure you I will have it for the absolute minimum time possible.

All the best!

Scott

Scott, I am new to the site and have read many different threads where you have commented. I purchased an M5 and was contemplating sending it to you when I read a post where you worked your magic on an old RCBS that you sold but wished you had not and were looking for another. Can you tell me what model you were referring to. I have a couple old RCBS scales but am leaning to doing my M5. Also I commend you statement above. It is easy to throw rocks when expectations are high. Regards, Gerry

 

[sparker]

Here’s the link to the 10-0-5 scales listing.

SELLING - A pair of Scott Parker Matched 10-0-5 scales

Two Ohaus 10-0-5 scales from mid 1960s. Both In box, in excellent to mint condition. Fully tuned, calibrations have been matched, pans are completely interchangeable between the two scales. Perfect for father and son, or two good shooting buddies. $550 shipped VLD223@yahoo.com 6613641199

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