FX-120i calibration weight; Does grade/class really matter?

[tsu45]

I was about to order an F1 class calibration weight on ebay after watching a youtube video on scale calibration. Started thinking about it, does that really matter for our purposes since we all do load workup and look for signs of pressure along the way? It's really just a relative measurement as long as my scale is calibrated to the same physical weight every time, shouldn't matter if my calibration weight is 49.987g (my RCBS chargemaster weight) or 50.000g.

I could see the importance if loading to an exact known max charge right off the bat with no load development, but that's not how any of this works.

 

[clcustom1911]

M2 certified 50g calibration weight +/- .010g

10mg is about .015gr. I use this just to make sure my scale isn't way off after warmup. If it is, I recalibrate with this weight and it reads 0.000. Your logic is correct in my opinion.

Edited to correct the mg to gr conversion.

 

[Jrb572]

I agree with as long as what you are using and doing is repeatable time after time.

 

[Sheldon N]

Agree with your thoughts.

However, check out ebay for used calibration weights. I found a Class 1 ASTM Troemner 50g weight for $30. Certified in it's cool little padded box. Totally unnecessary but a fun piece of bling.

 

[47guy]

I spent the $90 bucks and got the 100g ASTM 1...I figure I spent $700 on the scale and $550 on the V3 so $90 to make sure it’s all good was worth it to me.

 

[EnjoyTheWilderness]

Depends upon what you want to do with the scale.

If you are only looking to measure out powder, then having a scale that gives repeatable results is the primary thing. Calibration needs to also be repeatable. If the actual value of your weight is close to the nominal value then you should be fine. Cheap new weights without certification papers via eBay or Amazon are fine and generally good enough for this purpose. When going this path, consider your scale as being similar to something like a headspace comparator. The values you get work for you, but they are not absolute values that others can use. This is probably where most everyone is at today.

If however, you want to do things like measure other things accurately and share the values with others (with values that show a high level of accuracy), such as bullet or case weights, or calculate case volume via water or alcohol weight, then accurate calibration matters. Then knowing what the actual weight of your calibration weight is required. Note that weight class just is how far actual is supposed to be from the nominal value. And you dont ever know the "actual" weight unless you buy a calibrated weight (with associated paperwork that you trust), or you have someone measure it on a scale with traceability (that you trust). Note... most here may not care or need to go this far, but some (myself included) do care enough to do that.