Remarkable little scale

[JimSC]

checked my Gem 20 and it is consistently .02 grains lower than my A&D 120. For $25 it is the best scale I have found. Only drawback is it's small size

 

[Fast14riot]

Had an interesting issue with my Gem20 the other day. I was about 30 rounds into a session of charging 72 cases. Dumped the charge into the case, replaced the pan and suddenly the scale was creeping up in weight with an empty pan. About a full grain every 5 seconds, and just kept going.

I turned it off, back on, recalibrated, and it persisted. I though maybe batteries were running low. Picked up the scale to remove the battery cover to try spinning the batteries when I heard a faint rattle inside the scale.

Spun the batteries, replaced cover and turned back on, got a "OUTZ" error message on the display. Book says possible damage from over load. Shit.

I pick up and shake scale again. Still rattling. I close cover and turn it upside down and shake it, low and behold two kernels of H4831 and about a dozen flakes of ball powder come falling out from under the pan and the rattle is gone. Turn it on, recalibrate and everything is back to where it should be. Weighed 3 charges and verified on my tuned beam scale and all were good.

So, do check to see if powder is getting inside your scale from time to time.

 

[Ned Ludd]

I decided to order one of these balances for a couple reasons. First off, it's only $20, right? How bad could it be? Second, I figured it might be good to have a backup in case my analytical balance ever goes out right before a match (it might take a fair bit of time to order a new one online and receive it).

I just received the Gem20 yesterday and carried out a comparison with my Mettler Toledo analytical balance. I weighed out Varget powder (43.5 gr = 2.8188 g) by trickling up in the Gem20 until it just reached, and remained steady at, 2.819 g. I then transferred the powder to another dish on the Mettler, which was zeroed to that dish. Here are the raw data (in grams):



Although I can't remark on its reliability over time as yet, this little balance is pretty amazing in terms of its accuracy and precision. It was not difficult to achieve exactly 2.819 g readings for each powder sample by trickling up until it just reached that value. As you can see from the Mettler SD value (which I trust implicitly), the Gem20 gave approximately +/- .002g for 10 samples, which is very close to what would be expected given the .001 g readibility. That's pretty darn good for a scale that cost only $20. The average weight of a kernel of Varget is .0014 g, so with a little care, this balance appears to be capable of very close to +/- one kernel precision. I had no difficulty using my regular powder weighing dishes; they fit on the Gem20 pan just fine.

The only [very minor] criticism I can come up with at all for this little balance is that it is relatively slow in reaching a stable reading as compared to the Mettler. But again, it cost only $20. Thanks to BoydAllen for his original post about this balance! This is a nice little balance to have as a backup, or to use as a primary method of weighing powder. If I didn't already have the Mettler, I might purchase two or three of these just to have around.

 

[Geocodyrgia]

I think I may have been the apologetic one introducing this scale in the mentioned thread but I’m sure many others have found this little gem on their own. It’s been a great buy for me but I had no way to put it through the kind of paces many here could (as shown above) as it’s been my only digital scale.

I’m glad I can help possibly present an alternative that helps save some folks some money to be spent on better glass or a new barrel!

 

[BoydAllen]

I can throw light, and pinch trickle within +- .05 gr. in under 30 seconds.
GEM 20 wind shield by boydallen, on Flickr

 

[JimSC]

I can throw light, and pinch trickle within +- .05 gr. in under 30 seconds.

I use the same pinch trickle technique. It still amazes me that my fingers are sensitive enough to I can actually pick up one or two kernels of stick powder to top off a charge. Seventy five rounds charged to plus or minus .02 gns with bullets seated takes about an hour to a hour and a half depending on interruptions. Love that improvised wind shield

 

[46and2]

I can throw light, and pinch trickle within +- .05 gr. in under 30 seconds.
GEM 20 wind shield by boydallen, on Flickr

That is a well engineered wind shield. I wonder if a guy could use something like the bottom of a plastic juice jug?

 

[BoydAllen]

This is what I used.

 

[JimSC]

This is what I used.

I have a half empty one of those in my pantry, guess it will never see the recycle bin

 

[Fast14riot]

Figured I resurrect this thread, holidays coming and this scale could be an excellent little gift.

But, I haven't seen many videos of it in use, so I made one, just so those who don't believe the speed and accuracy of it can see it in use.

Still using this scale as my primary, just because its quick, doesn't take up much bench space and is inexpensive.

 

[rebs]

I have the Frankford Arsenal and like it so much I bought a second one when they were on sale

 

[rsmithsr50]

boyd..have you any data on batt life at the range.
the 250 was a disaster at the range for me

 

[strut64]

I had an ohaus 505 that seemed to be working OK. But I took a flyer on the little scale. Then The ohaus got wonky on me. I have never looked back. the little scales are remarkable for sure. They are sensitive to vibration and when the batteries are weak the will drift. Just watch for the tare to be off and take care. Very easy to calibrate.

 

[T-shooter]

I may order one just to try it. Wasted more money than that before. I have a cheap MTM scale and it does a good job but only reads to 1/10. It reads about 1/10 lower than my FX scale but I haven't calibrated the 2 together with the same weight. I use it for quick checking things like if I forgot to put powder in a case. I've had a couple other $10 cheapies that were not very good. One scale that works well considering it's cost was the GemPro-300. It weighed +/- .002 grains and out of 75-80 weighings, went .002 grain under only once. Yet again, they about about $150. I noticed with these smaller scales, if you set the pan down too hard, it will read differently. Set the weight or pan down like a feather will eliminate a lot of false readings. I have or have had and tested all these scales.

 

[BoydAllen]

boyd..have you any data on batt life at the range.
the 250 was a disaster at the range for me

Unless the platform is touched, mine turns off after about 40 seconds. I imagine that this has quite an effect for extending battery life, but I cannot tell you what the life is. Fortunately, warm up does not seem to be an issue. I pick the pan up and set it down a couple of times and I seem to good to go. If I have an issue and want to keep the scale from turning off I just tap it very lightly.

 

[AccelR8]

I may order one just to try it. Wasted more money than that before. I have a cheap MTM scale and it does a good job but only reads to 1/10. It reads about 1/10 lower than my FX scale but I haven't calibrated the 2 together with the same weight. I use it for quick checking things like if I forgot to put powder in a case. I've had a couple other $10 cheapies that were not very good. One scale that works well considering it's cost was the GemPro-300. It weighed +/- .002 grains and out of 75-80 weighings, went .002 grain under only once. Yet again, they about about $150. I noticed with these smaller scales, if you set the pan down too hard, it will read differently. Set the weight or pan down like a feather will eliminate a lot of false readings. I have or have had and tested all these scales.

As an inexpensive second scale what is your opinion of that Lee Precision scale? They are inexpensive enough but to me anyway the appearance of it does not say "precise."

 

[T-shooter]

As an inexpensive second scale what is your opinion of that Lee Precision scale? They are inexpensive enough but to me anyway the appearance of it does not say "precise."

I got that scale in a kit and it never got used. What a piece of crap. No matter how careful I was, I couldn't get consistent readings. I threw it in the trash and ordered the Hornady beam scale which is also not very accurate but better. I though it was good but later found out that if you slid the beam and pivots away or towards you about 1/16", it either lost or gained 1/10 to 3/10 grain either way. I gave up on it and went electronic. Trying to save money and finally just bought the FX300i. I even put small roller bearings on it which did seem to help a little but not enough. I tried removing the magnets, and also sharpening the pivots. It still acted the same for whatever reason.

This is the design of the factory pivots.

 

[JimSC]

boyd..have you any data on batt life at the range.
the 250 was a disaster at the range for me

I never kept track but I load around 50 -100 loads per week most weeks and the cheap batteries it shipped with lasted me over a month. Put some good name brand batteries in there and it should go 500 rounds but that is just a guestimate. As Boyd pointed out the auto shutoff works but can be worked around. I wish there was a way to mod it in the software to like 5 minutes but that would be at the expense of battery life because I know me and I tend to forget things like that. That's why I keep a plastic box with a couple of every battery type my equipment requires in my range bag. Sucks to get all unloaded and set up then discover you left your chrono on last time it was used and no batteries within 20 miles.

 

[AccelR8]

This is the design of the factory pivots.

I can see how that would be a problem.

 

[BoydAllen]

I got that scale in a kit and it never got used. What a piece of crap. No matter how careful I was, I couldn't get consistent readings. I threw it in the trash and ordered the Hornady beam scale which is also not very accurate but better. I though it was good but later found out that if you slid the beam and pivots away or towards you about 1/16", it either lost or gained 1/10 to 3/10 grain either way. I gave up on it and went electronic. Trying to save money and finally just bought the FX300i. I even put small roller bearings on it which did seem to help a little but not enough. I tried removing the magnets, and also sharpening the pivots. It still acted the same for whatever reason.
View attachment 1159881
This is the design of the factory pivots.
View attachment 1159882

I have played with a friend's Hornady and concluded that the bearings are the problem. You would have been much better off tuning a used American made RCBS . I have done several of those. Also, the magnets do not have any effect when the beam is still. The effect diminishes to zero with the beam motion.