Accurate Digital Scales

[Range Rector]

This topic may have been covered before.
But, who can recommend a digital scale that is accurate, reliable and relatively fast.
Resolution / accuracy of approx 0.02 to 0.05 grains and is constantly repeatable at an affordable price.

Thanks

[Pete]

GEMPRO 250 works well the degree of accuracy that you are after and at the cost of about $160.00. Repeatability though only became acceptable for me when I combined it with the RCB's Chargemaster 1500. They don't like single kernels (GEMPRO)taken or added repeatedly, the scale will begin to wonder from zero. If you throw the whole charge and then place it on the scales, get your reading and then remove the charge from the scale you can then remove the correct amount singularly. 2208 weighs approx. 0.02 grns a kernel, so I remove these by tweezers and then dump the load into the case. The Chargemaster generally throws within +/- 3 to 4 kernels to the required amount. Without throwing the charge reasonable accurately first I would not recommend these scales, but as stated work extremely well for me when employing the above method. Hope the above makes sense.
Regards
Pete
PS Of course Lab scales are on a whole new level of usability, repeatability and price.

[Barry Davies]

G'day Richie,

Cannot go past the A & D FX - 120-i
Fast, Accurate, Sensitive, ( 0.02 Gn ) Repeatable and all the other good features a reloader requires.
Shop around, you can pick up for around $900.
Dependable accuracy etc does not go hand in hand with cheap $.
I have a set of those as well as a set of the old FX320 and your welcome to come and use either at any time to satisfy youself they are the bees knees for reloading.

[higginsdj]

I have both. The 120i worked perfectly up until last weekend - then it started to drift on me for the first time since I bought them - 0.04 to 0.06 random jumps. I have my doubts any scales are perfect but it now means I !

The Gempro seem to drift less but I think this is because it appears to auto rezero itself on a regular basis.

Cheers

David

[ecomeat]

Richie,
I am with Barry. The AnD FX 120I's are superb scales. As he said, they are fast, precise and repeatable.
Mine were about $800 delivered ex SanDiego Scale Co,approx eighteen months ago but I remember someone on here that I had recomended them to sourcing a set ex Canada for about half of that !
Aaronrad posted a link on here a while back to a good YouTube video showing the accuracy abilities, and particularly overcoming the common problem of "creep", of these Magnetic Force Restoration scales.
My unqualified mind gains confidence from being able to reload to within 0.02 gr, and when used with the battery powered Omega Trickler and a powder thrower, they are also quite fast to use.
Tony

[pjifl]

I have only ever found one reliable way to completely defeat the auto zero capability on digital scales.

This auto zero is a sticky zero that causes problems even on the more expensive scales.
Often made worse because you cannot find out reliable information on it.

SOLUTION.
You deliberately introduce a definite offset which is an exact integer value so it can be instantly recognized and then weigh powder up to that value.

As an example.
My best digital scales weigh in Grams only.

I made a check weight as close as possible to 1.0000 gram.
And of course check weights of what I weigh out.
Such as, for example, 51.5 grains.

Then tare the scales with the pan PLUS the 1.0000 gram weight PLUS the 51.5 grain weight.

You can check at any stage during a weighing session by simply placing pan and 51.5 grain check weight on the scales.
It should read negative or - 1.0000 gram.


You simply add powder until the scales read negative 1 gram which is easy to recognize.


Using this technique, you can give the finger to all the pre programmed digital scales which have a stupid and uncontrollable mind of their own.

Of course, it involves negative numbers but you soon get used to that.
It would be possible to make check weights exactly 1.0000 gram under weight but I think that may be even more confusing.

Peter Smith

[williada]

Peter, that is an excellent tip. Thanks. David.

[DaveMc]

Peter - I agree but have a simpler approach.
I tare the powder pan and when removed, scales will sit at a -ve number so won't recalibrate to zero. I add a throw of powder o the pan and put on scales (now a positive number nowhere near zero) and trickle up from there.
The key to watching drift is just keeping an eye on the -ve value of the empty tray (sticks in memory well after a few thows) and rezeroing with empty pan when it wanders. Antistatic pads and earthing the scales can make a huge difference to the A&D - also a controlled air environment.

I found the gempro's infuriatingly slow and suffered issues with power variatons and other (especially in a caravan in campground with large powerboard conglomerations and voltage drop). You could of course set up with a constant power supply, UPS or similar but then it is bulky.


The A&D (Fx 120 or 300) if you can afford it is about the best value and when setup properly (with thower and omega trickler or similar) will have you thowing and weighing charges remarkably quickly and very accurately.

Dave

[williada]

C'est tres interesting, Dave. David.

[pjifl]

The reason I prefer an offset of an exact amount is that when working towards the offset I find there is less chance of an error if the target is exactly -1.000.
This represents a visual pattern rather than a number.

After loading a few hundred, it is amazing how easy it is to do.
And if you catch yourself half way through an error there is always a lingering doubt about all the preceding ones.

With the 1.0000 g offset, you simply remember the unloaded last digit and watch it when the pan comes off to check on drift.

I know that DaveMc and a few others also weigh the loaded rounds quickly afterwards to check for any gross error.
If the cases have been arranged in a box in weight order, it is a very good check.
Perhaps this is more for major shoots.

This started after one shooter had an unexplained shot about 2 min low one time and the most likely explanation was that the weighing was 1 grain out.
Calculations later matched this perfectly so it was a definite possibility.

Peter Smith

[6.5x55ai]

Peter - I agree but have a simpler approach.
I tare the powder pan and when removed, scales will sit at a -ve number so won't recalibrate to zero. I add a throw of powder o the pan and put on scales (now a positive number nowhere near zero) and trickle up from there.
The key to watching drift is just keeping an eye on the -ve value of the empty tray (sticks in memory well after a few thows) and rezeroing with empty pan when it wanders. Antistatic pads and earthing the scales can make a huge difference to the A&D - also a controlled air environment.

I found the gempro's infuriatingly slow and suffered issues with power variatons and other (especially in a caravan in campground with large powerboard conglomerations and voltage drop). You could of course set up with a constant power supply, UPS or similar but then it is bulky.


The A&D (Fx 120 or 300) if you can afford it is about the best value and when setup properly (with thower and omega trickler or similar) will have you thowing and weighing charges remarkably quickly and very accurately.

Dave

Months ago I bought 2 GemPro 250's off Amazon. The first one went back within 2 weeks and I got a refund. The zero had a mind of its own. The second one I wished I had also sent it back as although it is not as bad as the first one it also has an intermittent problem with the zero ramping.

I ran mine on the ac power supply provided, after finding that running on batteries it requires batteries to be absolutely charged to the max. If not it shuts down on low battery. The power supply is a switched mode type to give the ability to operate off a broad range of ac voltages. They aren't particularly clean at this level of cost. I have now made up a separate power supply using a 4x C Cell battery box from Jaycar. The scale now performs much more stably and the batteries last for ages. It also means I can power it up many hours b4 I need to use it and the batteries will still be OK.
I also do my weighing in grams instead of grains - OK once you get used to it. It means I can regularly throw on the 20 gram test weight to check cal.

[Pete]

DaveMC you are 100% correct and I do exactly the same thing to begin with, as I do not believe you would get the required accuracy any other way. I use a small plastic container (Chinese dipping sauce one I think and it weighs 18.52grns. When the charge is removed if -18.52 does not appear I know that the scales have wondered and therefore an inaccuracy has occurred. Electronic scales in the GEMPRO price range at least will not allow you to generally dribble powder time after time without beginning to accumulate error. NEVER trust the GEMPRO automatic zero, without having performed a physical check as above. They state 0.02grn accuracy and they are when not faulty, but not with accumulative weighing (mine does not at least), I don't add or subtract grains whilst the container is on the scale. Simply put, what would be more accurate, weighing your rifle as a assembled item or weighing the sum of its parts and adding the values??? This is why I use it in conjunction with the RCBS 1500 and simply remove the grns +/-, sometimes re-weighing depending on how far the thrown charge was to the true desired weight. Whilst doing this the RCBS is dispensing the next charge. Much quicker than it sounds!!!
Regards
Pete

[Range Rector]

Thanx to all replies.
Barry, what calibration weights do you use, are they the real costly ones?
Class 1, Class 2, or up to Class 6 test weights?
The FZ models have an internal calibration weight feature, just press CAL.
Haven't purchased anything yet, gotta think a little more, and, yeah, save some cash.

Richie

[AlanF]

Richie,

You started this thread asking about digital scales, so I've let it run without comment. But am wondering why you aren't considering balance beam scales. I've used a few digitals, up to around $400, and I keep going back to a Redding No 2, very accurate, no warm up time, no power supply issues, and with practice and good technique, quite fast. I have a cheap Lee thrower set up to drop directly into the pan on the scales, then trickle up to weight, then for important shoots, I add another step by taking the loaded pan and sitting it on a GemPro digital as a check. Normally the GemPro will be within +/- 0.02gn charge to charge. If it isn't I add or remove a kernel. I find that as a percentage of the total daily preparation process for shooting, loading cases is quite a small part of it. Prepping the cases actually takes longer, and cleaning the barrel(s) about the same.

I hope this gives you another option.

Alan

[Barry Davies]

Hi Richie,

My calibration weight cost nothing -- I made it.
Had the scale calibrated by the seller ( Bendigo scale Co ) then made the weight. Is accurate to within 1 milligram ( 0.02 gns approximately ) May vary slightly against other scales but at less than 0.02 gns who cares.
Also made check weights at various amounts to check scales during weighing.
Never had any problems with the FX 120-i apart from an occasional zero shift of 0.02 gns which is not really worth worrying about ( 1 granule of powder )
A good electronic scale will repeat within 0.02 gns --note I said good --not cheap. Forget about the cheap ( $300 -- $ 400 ) scales --they do not repeat accurately, are slow, and zero continually drifts.
If you are going to go electronic be prepared to spend at least $ 900. on something decent.