Did a Little Tinkering Today

U

uncle.45

New member
Hi, All!
I was bored earlier, and since I am waiting for the next 2,000 bullets to arrive from Acme Bullets, I did a little tinkering.
Scale calibration weights is a subject I have thought about lately, so I made a 3.5 grain weight with which I can check my scales.
After very carefully confirming Zero on both scales, I cut a 1 1/4" piece of paper clip wire, and nipped/filed it until my beam and electronic scale agreed that it weighed 3.5gr.
Then I made two 90 degree bends in the wire so it can't roll, and it will always have an end sticking up to grab. My electronic scale couldn't tell the difference, but after bending with dirty pliers, my beam balance showed the wire was heavy. Wiping it off made both devices show exactly 3.5gr again.
It was easy and didn't take long, but I think it was some useful tinkering.
https://www.dropbox.com/s/rc50fw547abtia1/20180329_162258.jpg?dl=0
 
Good job.

Some pharmacies will have a calibrated and certified scale that measures to 0.001 grams (0.015 grains and change). 3.5 grains would be 0.227 grams (3.503 grains) and if yours will weigh it for you, that would be an easy way to get confirmation and, if necessary, guide a slight adjustment.
 
Just trying to draw a parallel...

A 50 years old alarm clock, and the digital clock on a smart phone. The former has 3 hands. The latter display time in hh:mm format, but it is as accurate as any clock can be as it is synchronized to the GPS time base.

These 2 clocks display the exact time at noon. 15 seconds later, one can tell the time is past noon as the alarm clock's seconds hand indicates. But the digital clock on the smart phone still shows 12:00. One minute past noon, they tell the same time again.

The old alarm clock is better than the digital clock on the brand new smart phone?

-TL

Sent from my SM-G930T using Tapatalk
 
Go into the settings and ask it to display seconds. You can also tell it to give you a round clock face with a second hand in the display.

The idea behind a higher resolution reading is that over time the weight may pick up dust and oxygen as oxide (get heavier) or get scratched and worn (get lighter) and having a higher resolution value will make that stuff take as long as possible to happen and move it far enough off the nominal weight to cease to be a good calibration standard.
 
Thanks Unclenick!
It just so happens that I have made friends with the pharmacist at the local Sam's Club.
I hadn't thought about asking him, but I'm sure he will check things for me.
I'll let you know the results.
 
Unclenick said:
Go into the settings and ask it to display seconds. You can also tell it to give you a round clock face with a second hand in the display.
Click to expand...
Of course. The point of the parallel is all things digital has uncertainty of +/- 0.5 LSB (least significant bit). If the variation in quantity being monitored is less than the uncertainty, it is simply ignored as noise.

Most digital scales have LSB of 10mg, or 0.15gr. In op's case, the dirt could need to be as much as 0.075gr before the display would show.

-TL

Sent from my SM-G930T using Tapatalk
 
with reloading scales what you need to be concerned with is the precision not the accuracy Precision refers to the closeness of two or more measurements to each other while accuracy refers to the closeness of a measured value to a standard or known value.

If you are into long range shooting weighing needs to be super precise right down to .0001 grams. However 99 percent of shooters rarely if ever shoot beyond 400 yards. Up to 400 yards .1 grains is plenty accurate and precise. Just about any electronic from a 20 dollar scale off Ebay to a Gempro to a Chargemaster will get you to where you need to be. 100 yard benchrest shooters regularly shoot .1 and .2 groups with charges that are .2 or .3 grains apart
 
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I have it easy, I just used the check weights in our aviation instrument calibration shop. My older RCBS 5-0-5 is spot on through the entire range.
 
best way to check an electronic is to weigh 2 objects separately and then weigh them combined. Do this ten times. Try and find 2 objects that add up to what your normal load is or do a series in increments from 5 grains to 100 grains. BB's , paper clips and snipped off pieces of plumbers solder works for test weights.

If you want to see the anti drift of an electronic that has a readout of .1 grains in action here is how. Let the scale warm up for 1/2 hour, then zero the pan. Next take about ten or fifteen kernels of stick powder and start dropping them in one at a time with tweezers. The anti drift function will over ride the signal from the strain gage and keep the scale reading zero but when you lift the pan the scale will read - .2 or - .3 depending on how many kernels you dropped in slowly
 
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I got to got to the pharmacy yesterday.
After checking twice he said the wire weighs 3.482 grains.
I was surprised/pleased that he could measure to .001 grains!!
I would say that's plenty accurate for double-checking my most-used loads of 3.5 grains.

Guffey, I bent it the way I did so that no matter how it lays part of it will stick up to be grabbed.

It was a fun, useful little project. :)
 
Guffey, I bent it the way I did so that no matter how it lays part of it will stick up to be grabbed.
Click to expand...

That does not change the need for tweezers, I have two sets of Ohaus check weights, both sets come with tweezers. And then it has to do with expense, some metals are more expensive when it comes to check weights. Companies that make check weight discourage handling the weights with the hand.

Wire weights in both sets are bent to aid in handling with tweezers,

F. Guffey
 
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Tweezers to keep weights clean.
Nonmetallic tweezers to not scratch off a few tenths of a milligram.
Old analytical balance on display at Tech chem lab had ivory tipped tweezers.
 
.000" sorry but I don't think I could discern that amount on the pointer of my scale. At least not with these eyes!
 
Jim, I'll bet those tweezers cost more than my whole reloading setup.
kmw, I, too, am getting to have O.G.E.s. (Old Guy's Eyes)
 
I have my beam scale set up on a platform so that it is at about eye level and in the front of the scale pointer I have a cheapo 3" magnifying glass taped on. works very well!
 
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