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Which Scale Check Weights?

exactly, we are not selling gold or compounding pharmaceuticals so whether a checkweight is 45.2 gns or 45.3 or 45.1 is not relevant to what we are going for. What is important is that same check weight still registers 45.25 grains today, tomorrow and a year from now. I find either a .22 LR or some other 40gn bullet works well for me becasue that is close to all my favorite loads

I also calibrate my scale with 30 grams rather than 100. In the Navy we were taught that a torque wrench is most accurate in the middle of it's range and figure the same logic applies to load cells, maybe not but scale seem sensitive enough to me
That's what I was trying to say! Dido.

Darrin
 
100grams is 1543.246 grain. Kinda far away for checking powder charge linearity

It is what the makers of the scale says to use...the RCBS comes with 2 50 gram weights or 100 grams total. The Dillon comes with one 50 gram...I don’t think it has to do with whether you are weighing powder or diamonds...
 
exactly, we are not selling gold or compounding pharmaceuticals so whether a checkweight is 45.2 gns or 45.3 or 45.1 is not relevant to what we are going for. What is important is that same check weight still registers 45.25 grains today, tomorrow and a year from now. I find either a .22 LR or some other 40gn bullet works well for me becasue that is close to all my favorite loads

I also calibrate my scale with 30 grams rather than 100. In the Navy we were taught that a torque wrench is most accurate in the middle of it's range and figure the same logic applies to load cells, maybe not but scale seem sensitive enough to me

The fx120 has a 1 lb. sensor so having 100 grams makes sense and I think you are right. A good weight cost so much because if it says 50 or 100 grams you want to know it does! The two weights with my RCBS are 5grns difference from one to the other. A flake of gold plating wears off and there you go...
 
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I have a TROEMNER 100 Gram CLASS 1 CALIBRATION WEIGHT. Class 1 would be the the most precise. (I think). this is for use on my fx120i. using this i found that from the retail place i purchased it from, their calibration was off 0.644 grains.

You can sometimes find good, used deals on Ebay for Class 1 calibration weight. I picked the 100 gram because it's set by default. you can change to the 50gram weight.


Same here. Class 1 I have a troemner. They are like 80-100 bucks. Come with a glove to pick it up too.
 
The guys using the Aluminium powder cup from Area419 on The FX120I would be getting close, that cup looks heavy..

It weighs slightly over 700 grains. Roughly 45 grams.

Fx120i resolution is 0.001g - 122g. Plenty of room.
 
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I'm not too concerned about an inert chunk of metal somehow becoming unreliable.

Are most metals inert ? I'm no chemist, but I don't think so.

Exact weight matters none. The best check weight is a bullet that you scratch the weight into and keep with the scale. No need to waste money on check weights

Check weights are designed to resist corrosion, and have storage and handling features to prevent contamination (e.g. from grit & corrosive finger grease), to work with special handling tweezers that hold the weight securely (avoid dropping/damaging/contaminating) and to sit stable when placed in the centre of a balance pan.

I agree that absolute precision is not usually necessary, so the more expensive weights can be avoided. I bought a 50g and a 5g weight, in order to check linearity and to have a quick check-weight close to the region in which I'm weighing; in practice I rarely use the 5g weight, but I do confirm the calibration every day I use a balance.

btw: How do you scratch the weight, and correct for the change in weight caused by scratching the weight?

...and how do you calibrate the balance that you use to weigh the weight before you scratch the weight?


VA2H0129.jpg
 
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How do you scratch the weight, and correct for the change in weight caused by scratching the weight?

Scratch the scal reading first, then tweak until it matches

and how do you calibrate the balance that you use to weigh the weight before you scratch the weight?
Doesn't matter. If the weight balances at a specific point & the check weight matches, then when you return to using that load, you set the scales for the mass of the weight you want to use.

Hey, for decades we were happy with balance scales that the manufacturer claimed only +- .1 grain. I could achieve that variation on a single pan of powder depending whether it lay towards the pointer of the scales, towards the other end, or uniform across the bottom of the pan.

A check weight for a specific load gets it right every time, to your skill in manipulating the scale.
 
What's wrong with the RCBS or Lyman check weight sets at around $40? I've checked my set against a good calibrated lab scale and found they were too close to worry. They are grain weights and by combining weights you can make up a weight very near the load you intend to use. If you want to be using a powder load of 36.5gns just make up the exact weight (20,10,5,1,.5) with the check weights and make sure your scale reads zero and repeats at that weight. In fact, you don't even need any numbers on your scale.

 
I have a TROEMNER 100 Gram CLASS 1 CALIBRATION WEIGHT. Class 1 would be the the most precise. (I think). this is for use on my fx120i. using this i found that from the retail place i purchased it from, their calibration was off 0.644 grains.

A 100 gram weight that is off by 0.644 grains is Class 7, not Class 1, but that isn't what is really important. What is critical is that you know the exact weight within a known degree of uncertainty.

Check Weight Classes 2016-06-05_11-49-54.gif

These types of sets are very accurate as they were made to calibrate actual pharmaceutical scales. These weights were in common use up through the late 1990's when digital scales became the norm. The set above probably cost over $400 when brand new.

Calibration weights are still widely used today to verify some very accurate (and expensive) scales and balances. A good set with calibration certificates is expensive.

I use a set that was found and given to me by a friend who drove a garbage truck, but I compared them on a laboratory analytical balance against a set of calibration weights for which actual weight was established by the state Weights and Measures laboratory and known to a degree so fine I could never distinguish myself. My company paid almost $1,000 for this service.

Yeah, overkill by magnitudes for scales that only read to 0.1 gr.,, but I had the capability at the time and I'm just a little bit OCD. Most people on this forum, and this section in particular, share the same trait.

Ideally your scale should be checked at zero and across the range you will be weighing. My highest powder charge is not quite 100 gr. Add the tray and it's still under 150 gr. I check at 0, 100 & 200 gr. and that's fine.
 
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I have a set of these: https://www.ebay.com/itm/Troemner-A...d:g:vvwAAOSwpHpbCZi4:rk:2:pf:1&frcectupt=true

They are actually 2 complete sets, one is metric and the other is in the traditional apothecary weight system which is based on grains. These types of sets are very accurate as they were made to calibrate actual pharmaceutical scales. These weights were in common use up through the late 1990's when digital scales became the norm. The set above probably cost over $400 when brand new.

I must be missing something. I see no check weights in grains there.

Danny
 
What's wrong with the RCBS or Lyman check weight sets at around $40? I've checked my set against a good calibrated lab scale and found they were too close to worry. They are grain weights and by combining weights you can make up a weight very near the load you intend to use. If you want to be using a powder load of 36.5gns just make up the exact weight (20,10,5,1,.5) with the check weights and make sure your scale reads zero and repeats at that weight. In fact, you don't even need any numbers on your scale.

Nothing is wrong with them.
In fact comforting to have them .
Tell me about that old scale in the picture, very cool
 
Sometimes I think we overthink these things. If all it took to get flat velocities then all we would have to do is use a scale with a resolution of .0001 and a fine ball powder and have extreme spreads of 0. Anyone ever looked in a load manual and seen a starting charge of 2.588 grams ?
 
I must be missing something. I see no check weights in grains there.

Danny
The guy posting the ad doesn't know what he has. I have this exact set. The upper row and midlle row of smaller weights are all in Drams, Scruples and Grains.

A Troy ounce = 480 grains
An Apothecary Dram (not fluid dram) = 60 grains
a Scruple = 20 grains
 
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