flighty scales

[abolter]

I have a set of lyman electric automatic scales and am generally very pleased with them. However, every now and again they get so that the display/scales wont settle and they go up and down a few 10ths of a grain whilst stationary!!

 

Anyhoo I waas checking out tinternet and someone suggested a magnet to clip around the transformer cable. I have tried it and it has settled everything down, loaded 100 bullets last night with never a hint of a flicker!!!

 

Just thought it might be useful

[John MH]

Are there any air currents/draughts moving over the pan?

[DaveT]

Or fluorescent lights nearby or the table being wobbled or do you let the scale 'settle' for 30 minutes before using it?

[abolter]

tried all of the above and then read this article saying small spikes in current could do it! Probs seem solved with magnet in place and nothing else changed

[kent]

Its an interesting one. My friend is a chemist and although he doesn't shoot when I told him the tollerances I wanted he said forget electronic unless you have Lab conditions and calibrations. I only use electronic for weighing shot now

[gbal]

Its an interesting one. My friend is a chemist and although he doesn't shoot when I told him the tollerances I wanted he said forget electronic unless you have Lab conditions and calibrations. I only use electronic for weighing shot now

Nice point-my neighbour is an engineer,and always asks

"'what calibrated the calibration system?"

Gbal

[onehole]

Nice point-my neighbour is an engineer,and always asks

"'what calibrated the calibration system?"

Gbal

nice one !!

[Dark Star]

Its an interesting one. My friend is a chemist and although he doesn't shoot when I told him the tollerances I wanted he said forget electronic unless you have Lab conditions and calibrations. I only use electronic for weighing shot now

 

With the greatest of respect to your friend, what type of scales would he suggest which don't require any sort of calibration?

 

As long as you avoid the usual sources of interference as mentioned, such as air currents, fluorescent lights, static electricity and you have a calibration weight to set up the balance properly, then a decent electronic balance is the best way to fine tune powder charges quickly and reliably.

 

The scales attached to the Lyman, RCBS etc. auto powder throwers don't really have the correct type of load cell in them, so they aren't the most reliable, but they aren't bad for the money.

[kent]

 

With the greatest of respect to your friend, what type of scales would he suggest which don't require any sort of calibration?

 

As long as you avoid the usual sources of interference as mentioned, such as air currents, fluorescent lights, static electricity and you have a calibration weight to set up the balance properly, then a decent electronic balance is the best way to fine tune powder charges quickly and reliably.

 

The scales attached to the Lyman, RCBS etc. auto powder throwers don't really have the correct type of load cell in them, so they aren't the most reliable, but they aren't bad for the money.

 

The point was more the amount of things that can send them screwy and the difficulty of calibrating. He also mentioned the sort of cost of "proper kit" Still they are much faster than beam scales

[John MH]

Calibration is to ensure that they read the correct weight to within a stated tolerance. Knowing that the scale is reading the correct weight is secondary to it being repeatable for a hand loaders needs, I use a tuned balance beam scale that I 'believe' is repeatable so that the same weight of charge is trickled up each time I use it; whether that is exactly 46.1, 46.2, 46.3 or 46.4 grains is not as important as each one being 46.x, 46.x, 46.x and 46.x where x is always the same.

 

A UKAS accredited mass lab would be able to check your scales but its like an MOT only really good on the day it was done.

[gbal]

Calibration is to ensure that they read the correct weight to within a stated tolerance. Knowing that the scale is reading the correct weight is secondary to it being repeatable for a hand loaders needs, I use a tuned balance beam scale that I 'believe' is repeatable so that the same weight of charge is trickled up each time I use it; whether that is exactly 46.1, 46.2, 46.3 or 46.4 grains is not as important as each one being 46.x, 46.x, 46.x and 46.x where x is always the same.

 

A UKAS accredited mass lab would be able to check your scales but its like an MOT only really good on the day it was done.

Agreed,with the implied proviso that whatever the repeated measure is,is tolerably close to what you want it to be (to avoid over pressure issues etc.)

 

The concept is essentially the same as precision (group size) and accuracy (hitting the target).

 

And the more generic 'reliability' (gives the same measure/result each time) and 'validity '(measures what you think it measures/does what it says on the tin).

 

Confusing them or not specifying which ,is the source of some unwitting mischief on this site.( not by John MH) and elsewhere in life-you need both.

 

Gbal

[John MH]

My beam scales are close enough to my electronic Denver Instrument and the cheap check weights from RCBS that, provided you use good reloading practice and start to work up loads from 10% below the published maximum charge, over pressure and unsafe reloads can be avoided. Common sense helps as well.