Myth Busting Digital Scales - 1 mg Analytical Lab Scale for $120?

[jmorris]

I’m using an A&D fx120 and Autotrickler. Sure, it will resolve down to 1 kernel of powder (0.02gn), but the biggest benefit for me is the speed, consistency and time saving

Add cost in there and that’s the direction I went.



I do have a very lightly used (cover hasn’t even been off) A&D FX 120i I could let go, I have learned what I needed to from it.

 

[LiveLife]

A&D fx120 ... will resolve down to 1 kernel of powder (0.02gn) ... If you’re competing in a precision rifle sport, you’ll probably want to measure to the kernel, but it’s not necessary for most people

With "measure to the kernel" as inspiration, I continued my Vevor digital scale testing.

NOTE: I am finding that the scale definitely requires 15-20 minute, preferrably 30 minute warm up for more consistent readings. And like many digital scales that specifies operating temperature range of 59F-95F, I am also finding operating the Vevor scale near the extreme "normal room temperature" range can also affect consistency of readings.

I live at the coast and nightly low has been in the 50s with last night 51F and the scale has been kept in the kitchen covered but with windows open. Since it's summer time, keep this in mind if your ambient temperature is above 95F+, your reading consistency could be affected.

Above close up picture of Varget shows that while kernels may look consistent in length to naked eyes, actual lengths can vary and weight of each kernel can vary also based on length and cut shape.


Measuring sensitivity/detection - So after 30 minute warm up, I started weighing kernels of Varget. (I used the pan from Ohaus 10-10 which weighed 139 gr and when measured 10 times, scale showed 139 gr mostly with occasional 138.9 gr)

• 1 kernel - No reading
• 2 kernels - No reading
• 3 kernels - No reading
• 4 kernels - Depending on kernel size/length, readings ranged from 0.004 g to 0.006 g (.08 gr to .12 gr) with most of readings at 0.005 g (.10 gr).

Interesting thing is once 0.004 g is read, it kept reading 0.004 g even though I transferred the 4 kernels off the pan and dropped them back. Same for 0.005 g reading kept reading 0.005 gr as I repeatedly transferred the kernels off the pan and dropped them back.

Adding 2 more kernels would read 0.006 g to 0.007 g and adding 4 more kernels would read around 0.010 g (.15 gr - .16 gr).

So this is in line with my testing with check weights down to 5 mg (.08 gr).


Weighing additional kernels - Once 0.005 g reading has been established even after several transfer of 4 kernels off the pan and back, I started adding additional kernels and each kernel would increase reading by 0.001 g to 0.002 g (.02 gr to .03 gr) depending on the size/length of kernel I added.

With hope, I attempted to weigh 2 to 3 kernels again but without success. This digital scale is only sensitive down to 4 kernels of Varget. But for powder trickling, scale consistently detected additional kernel of Varget.

 

[Bill M.]

Actually sounds like a great scale for the money. Going all the way to zero is maybe too much to expect. I have done a lot of laboratory weighing. Very small weights are weighed in a container of some sort with a net and tare. We had a set of glass bottles with fitted glass stoppers to tare and weight small stuff in. So you maybe be being too picky in your tests. As long as it is sensitive and linear above 2 grains it ought to be great for reloading. All my reloading scales have used a cup for the powder with a spout and tared to zero.

 

[LiveLife]

So you maybe be being too picky in your tests.

Obviously you haven't met our THR peanut gallery.

They keep members honest and on our toes so our method, consistency and sample size of testing is sufficient enough and more objective. Their combined work/life experience have helped me stay objective with measurable and repeatable data collection for my myth busting threads so I appreciate their critique and input (BTW, thanks to Nature Boy and jmorris who have helped me improve my testing approach and accuracy testing).

And yes, this is a "myth busting" thread so I am definitely going to push the limits and extremes of this scale to determine the point of breaking (rather limits of sensitivity, detection and repeatability). I have already tested the low temperature extreme of 51F and the scale definitely needs warmer room temperature and sufficient warm up of 30 minutes for more consistent readings.

I have done a lot of laboratory weighing. Very small weights are weighed in a container of some sort with a net and tare. We had a set of glass bottles with fitted glass stoppers to tare and weight small stuff in.

Yes, this has been pointed out by some of the members and I will be doing that testing as well along with setting up the scale with drilled hole draft shield plate for powder trickling testing.

Going all the way to zero is maybe too much to expect.

As long as it is sensitive and linear above 2 grains it ought to be great for reloading. All my reloading scales have used a cup for the powder with a spout and tared to zero.

I am monitoring the consistency of scale's ability to hold zero vs temperature. One thing I am finding is allowing sufficient warm up time is increasing holding of zero.

We are just starting out with durability and repeatability testing of the scale so in time, we should find out how consistent scale ends up performing.

 

[Archie]

I will keep an eye on this thread.
When I started weighing cases for uniformity, I decided a balance beam scale was too slow. Not to mention the vague nature of 'reading' the 'oscillation' of the pointer.
I still have a balance scale, but seldom use it. I load mostly for rifles, so a veriation of .1 grain is largely ignorable when dealing with charges of over thirty-five grains. And I serious doubt many of the commercial concerns weigh each charge individually.

But I am interested in getting the best scale I can, given my funds.

 

[LiveLife]

I will keep an eye on this thread ... I am interested in getting the best scale I can, given my funds.

And that's the part of reasons why I am conducting yet another myth busting digital scale thread - To give THR members and guests another scale option that is suitable for reloading, especially for those on a tighter budget while shattering internet notions/myths about sensitivity, detection, repeatability and durability of digital scales as we have already busted some myths and proven in previous myth busting threads that even cheap $20 digital scales like Gemini-20/WAOAW can demonstrate higher resolution than beam scales. (But note that not all digital scales will verify check weights down to 5 mg/.08 gr with consistency and why I suggest the use of check weights regardless whether you are using beam or digital scale)

I am planning to do powder trickling comparison weigh off using plastic dome over Gemini-20/WAOAW scales and drilled draft shield plate for Vevor scale so stay tuned.

When I started weighing cases for uniformity, I decided a balance beam scale was too slow. Not to mention the vague nature of 'reading' the 'oscillation' of the pointer.

I found keeping the agate stone bearings and posts on my Ohaus 10-10s and RCBS 5-0-5 beam scales clean to "free float" the knife edge enhance maintaining repeatable zero and more consistent readings. Both of my 10-10s have sensitivity/detection of less than .1 gr - https://www.thehighroad.org/index.php?threads/talking-about-scales.862194/#post-11371715

And as jmorris demonstrated in the video in post #26, beam scales can be accurate and repeatable with relative speed depending on usage and set up - https://www.thehighroad.org/index.p...lab-scale-for-120.873830/page-2#post-11627394

I load mostly for rifles, so a veriation of .1 grain is largely ignorable when dealing with charges of over thirty-five grains. And I serious doubt many of the commercial concerns weigh each charge individually.

Commercial ammunition manufacturers use high speed automated fixtures that drop powder charges (5:00 minute of Federal video) and reloaders hand trickling to exact weight to the kernel will produce weight variance of powder charges of less than .1 gr (As each kernel of rifle stick powder like Varget weighs around .02 - .03 gr).

At 6:00 minute of Federal video, consistency of powder charge is pressure tested and accuracy tested to produce 1.5" groups at 200 yards.

 

[jmorris]

I am monitoring the consistency of scale's ability to hold zero vs temperature. One thing I am finding is allowing sufficient warm up time is increasing holding of zero.

Might download the data sheet for the load cell and see if your results match as far as creep temp effects on zero, span and such.

 

[LiveLife]

Might download the data sheet for the load cell and see if your results match as far as creep temp effects on zero, span and such.

Very good point as I also remind members when they complain about digital scales acting up/being inconsistent to check if operating temperature range is within manufacturer's specified range and consistent.

Since I already noticed readings affected by temperature change, I will conduct future testing while recording ambient temperatures and will repeat testing at same/similar temperatures and why allowing the digital scale to "warm up" sufficiently may be a key factor in repeatability.

Unfortunately the scale did not come with any documentation and vendor website did not have any pdf manuals to check the scale specifications.

And -10C/40C is 14F to 104F while most of my digital scales recommended operating temperature range of 59F to 95F and I already noticed inconsistency at 51F that our local ambient temperature reached last several days.

 

[jmorris]

You would need to take a peek inside to figure out what loadcell they used.

This is the one used in the CM1500
http://www.hzloadcell.com/pid114862...ingle-point-load-cell-for-jewellery-scale.htm

 

[buck460XVR]

I believe there are no free lunches, and that with like most things in life, you get what you pay for. Powder scales are no different. The more you pay, generally the better quality you get, whether it be digital or beam. I have both. I prefer my beam as I don't have to wait for it to warm up and it is not impacted by the amount of environmental factors as the digital. For the most part my digital is used to verify the weight on my beam. Then for the majority of my reloading, cases are charged by a powder thrower and every so many charges are verified to make sure the thrower is still on. I believe this is the route the majority of reloaders take, and accuracy of even sub$100 scales, beam or digital and their .1+/- accuracy is all we will ever need. I realize there are some that need ammo more accurate, or just want ammo more accurate than they are, so having the best and most precise is important. But for most of us? Got a friend that uses a RCBS chargemaster for his .45 ACP ammo. He weighs every charge. He shoots about 200 rounds a year. But he enjoys it.

 

[LiveLife]

I will open up the scale to see what load cell is being used.

I am working outside with wife building her chicken house so it will be later in the evening.

 

[w296]

I have decided to extend my myth busting of digital scales for reloading - https://www.thehighroad.org/index.p...tal-scale-accuracy.759750/page-4#post-9591790


American Weigh Scales Gemini-20 milligram scale has worked well for me the past several years since the initial myth busting digital scale thread - https://americanweigh.com/product_info.php?products_id=580

• 20 gram capacity / 308 grains
• .001 gram readability (displays grains in .02 increment)
• +/- .002 gram repeatability
• 2 AAA batteries
• Actual sensitivity down to .04 grains

WAOAW W-01-50 milligram scale has also worked well for me going on almost 3 years - https://www.amazon.com/WAOAW-Milligram-Reloading-Calibration-Batteries/dp/B06W5VXN53

• 50 gram capacity / 771 grains
• .001 gram readability (displays grains in .1 increment)
• +/- .005 gram repeatability (various internet sources)
• 2 AAA batteries
• Actual sensitivity down to .06 grains

Due to many positive member reviews, I thought about buying GemPro 250 but it went out of production. While A&D FX 120i would be nice, cost is beyond many reloaders' budget. And I seriously thought about buying Ohaus SPX123 Scout but at $390 on Amazon, it's also beyond many reloaders' budget, especially for new reloaders - https://www.amazon.com/Ohaus-SPX123-Portable-Balance-0-001g/dp/B01AJ089PS

So while browsing different digital scales and reading reviews, I came across this "Analytical Lab" scale on Amazon for $119.99 ($113.99 with $6 instant coupon applied) - https://www.amazon.com/gp/product/B087CCTZR9/ref=ox_sc_act_title_1?smid=A12NCJ26NT4XUM&psc=1

• VEVOR Analytical Lab scale
• 100 gram capacity / 1543 grains
• .001 gram readability
• AC adapter

There is very little information on this scale I could find but found this about the company - https://www.vevor.com/

And this - https://www.walmart.com/browse/vevor/YnJhbmQ6VkVWT1Iie

Scale is due to be delivered first week of September so I will update with unboxing performance and check weight verification to see if this scale is good enough for reloading or unreliable scale that needs to be returned.

View attachment 937957
View attachment 937958

 

[w296]

I like the vevor analytical balance 200 but only if I could remove the drift panel assembly. It looks like it would be a pain to have to use it for my purposes. Could someone tell me if that's possible.

 

[w296]

In the meantime, I have ordered from Amazon the
American Weigh Scale Gemini Series Precision Digital Milligram Scale, Silver 20G X 0.001G (GEMINI-20) (Black)
Sold by: iServe
$32.99 The reviews looked decent and for 32 bucks I will roll the dice. Thanks to everyone for their input

 

[LiveLife]

I like the vevor analytical balance 200 but only if I could remove the drift panel assembly. It looks like it would be a pain to have to use it for my purposes. Could someone tell me if that's possible.

Actually, rather easy to remove the draft shield panels.

Top cover is held by hex head bolts and 1/8" Allen wrench will fit (But likely it's 3mm Metric wrench as it took some effort to shove the wrench into the heads).

I just loosened the two right side bolts as I am planning to replace the right side panel with a hole to allow the tip of powder trickler through.

 

[LiveLife]

UPDATE: Disassembly to check load cell for jmorris

You would need to take a peek inside to figure out what loadcell they used.

I will open up the scale to see what load cell is being used

I removed the round platform and round flat cover to take the "load" off the load cell before tipping the scale on its side.

Battery cover was held with a Phillips screw (BTW, this scale is rechargeable as shown by battery charge indicator below the level indicator circle on the left side of display)

Picture of battery cover off (I found later that I didn't need to remove the battery)

And here's the battery

7 Phillips screws held the base (4 at each corner and 3 for front display panel cover) and top came off without needing to remove the battery. Load cell shown with rectangle steel plate base held by 4 Phillips bolts (This was key to "fine tuning" the scale for more consistent zero and repeatable readings - See next post on "fine tuning" this plate)

Here's the load cell showing cylinder at top where round weighing platform and cover goes (Load cell is held by two bolts mounted to the rectangle steel plate where black wire is coming out of and rest of load cell is suspended above the plate)

And here's the markings on the load cell (jmorris, this is the only markings on the load cell)

 

[LiveLife]

UPDATE: Fine tuning load cell mount plate

NOTE: DO NOT use magnetic screw driver or sources of magnetic field around the scale.

TIP: Level the scale with adjustable feet until slight force down on each corner won't affect display reading.

I turned on the scale (On battery power) and quickly found out magnetic screw driver around the load cell was affecting the display reading.

Out of curiosity, using non-magnetic screw driver, I applied slight force down near each of 4 mount screw and found 2 of them affected readings by .003 - .005 gram. So I loosened all the screws and display did not show change when I applied slight force down near each mount screw. Then I incrementally lightly tightened each mount screw while checking slight down force. (Too much tightening and display changed from "0.000 g")

I got to the point where I lightly tightened the 4 mount screws where pushing down near each mount screw did not change the display of "0.000 g".

With my zero now not affected by twist/flex of the steel mount plate, I calibrated the scale (Still with the cover off but all the windows/doors closed as air movement affected display reading) with the 100 gram calibration weight and started verifying Ohaus ASTM Class 6 check weights. (TIP: Level the scale with adjustable feet until slight force down on each corner won't affect display reading)

Guess what?

Absolutely no drift of zero and no need for "tare".

Scale still with cover off verified check weights down to 0.005 gram (5 mg/.08 gr).

I put the cover back on and noticed too much tightening of any screw could affect display reading so go easy on the screws.

Thanks to jmorris who made me open up the scale to check the load cell, I learned a valuable takeaway - When load cell mount plate is not mounted/tensioned properly and used out-of-level, it could affect consistency of readings.

Next test is making a side panel with a hole for tip of powder trickler.

 

[Blue68f100]

On the RCBS CM1500 the load cell has 2 mounting screws if not evenly torqued will cause the scales to drive and give erratic readings. Both of these screws have sealant on them. So if you have on that's drifting, it's something to tweak to stabilize it. I had spilled some powder that became a mess so I decide to take it apart and clean it out.

 

[LiveLife]

Scale was shipped with 220V adapter (Uses 12V DC 300A)

So after I send a message to the seller using Amazon "Problem with order" button, I find my universal DC adapter I used for laptops and viola!, scale powered on.

Thought I posted reply from seller already but apparently not.

Seller's reply was quick through Amazon message feature and email requesting verification of scale/adapter pictures.

Once received, seller offered to replace the adapter with $12 refund.

 

[Bafarett]

There are a lot of scales on Amazon; you just have to know exactly that they are of good quality, but how do you do that? Read the reviews or go to the forum and ask other users for an objective opinion from them. That's how I ended up buying this body scale from vont.com, which I've had for half a year. I'm glad that not only does it weigh the muscles, but it also tells you how much fat and water you have in your body, which is why I need to know, especially since I started dieting and sports, because I have a well-defined goal, to lose weight.

 

[LiveLife]

There are a lot of scales on Amazon; you just have to know exactly that they are of good quality, but how do you do that?

By checking them against known standards like check weights for accuracy/sensitivity and repeatability. If you are buying from Amazon with free return, then test the scale with check weights and return if the scale will not verify check weights.

And not all check weights are created equal. While ASTM Class 0-3 would be ideal, for verifying reloading scale that just needs to be accurate to 0.1 grain (6.5 mg), ASTM Class 4-6 would be fine for me - https://www.scalesplus.com/blog/what-are-calibration-weight-classes/

Here's made in USA Troemner (ASTM Class 6/NIST Class F) 0.5 gr to 50 gr (0.5-5 gr aluminum/10-50 gr stainless steel) check weight set that should be sufficient for average reloader at $18 - https://www.amazon.com/Troemner-151...rds=scale+check+weights&qid=1648480726&sr=8-8

If you want to verify accuracy of scale further, this set that goes down to 10 mg (0.15 gr) should be sufficient for $13 - https://www.amazon.com/Bekith-Preci...97-d69b-418f-af74-c4cf38449d24&pd_rd_wg=3mHVQ

I use Ohaus ASTM Class 6 stainless steel 500 mg - 1 mg check weight set that goes down to 1 mg (0.015 gr) for $79 + free shipping - https://www.zoro.com/ohaus-calibration-weight-set-500-to-1mg-80850110/i/G0843236/

Yes, there are many digital scales on Amazon/ebay and the reason why I decided to choose Vevor brand is because they seemed to be a large distributor of commercial/industrial products including industrial scales - https://www.walmart.com/search?q=vevor+digital+scale

I saw several vendors selling similar/same exact looking "analytical/lab" type scale and figured they all used the same load cell but with different branding/base housing. So I decided to buy one to test for THR myth busting thread and found it had sensitivity down to 0.08 gr (5 mg) and was able to resolve addition of Varget kernels by 0.02-0.03 gr (1-2 mg) depending on the length of kernel/cut shape.

I am waiting on the new Creedmoor Sports TRX-925 digital scale with claimed 0.01 gr resolution (Ships with three ASTM Class 3/F1 class weights) to test against Ohaus 1 mg (0.015 gr) check weight and even ordered additional United Scientific 1 mg - 500 mg fractional check weight sets - https://www.zoro.com/united-scientific-fractional-weight-set-with-rider-and-for-fwb500/i/G3628747/