Which scale to believe

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oldham

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I recently purchased a Frankford Arsenal DS-750 Digital Scale to verify the accuracy of my Lee Safety Powder Scale. Before measuring the powder, both scales were calibrated according to respective manufacturer. A 4.0 gr of HP-38 on the Digital scale reads less on the Lee scale. I must admit I find it a little bit difficult to interpret the tenths on the Lee. Those of you who are familiar with the Lee know what I'm talking about. I set the Lee scale at what looks to me as 4.0, but when powder is added to the pan, it registers low. Which scale is right and which would you use to load? Oh, let me add, I'm 73 and using some old and tired eyes. :confused:

I look forward to your replies. Thank you.
 
oldham said:
I recently purchased a Frankford Arsenal DS-750 Digital Scale to verify the accuracy of my Lee Safety Powder Scale. Before measuring the powder, both scales were calibrated according to respective manufacturer. A 4.0 gr of HP-38 on the Digital scale reads less on the Lee scale. I must admit I find it a little bit difficult to interpret the tenths on the Lee. Those of you who are familiar with the Lee know what I'm talking about. I set the Lee scale at what looks to me as 4.0, but when powder is added to the pan, it registers low. Which scale is right and which would you use to load? Oh, let me add, I'm 73 and using some old and tired eyes. :confused:

I look forward to your replies. Thank you.
Click to expand...
Is the measurement you are getting on the digital repeatable? Have you double (and maybe triple) checked the calibration on the digital with something of a known weight and gotten repeatable results? That's how I determine which one to believe. When I first started reloading all I had was the Lee scale and I HATED using it. I'm much happier and more confident in my weights now that I'm using a digital scale.

Btw: I'm only 36 and have paid good money to have my eyesight improved and I still prefer digital scales.
 
A man with one watch always knows what time it is, a man with two is never sure.

If safety is you goal use the one that reads lower than the other. How much of a difference are you getting? Draft (like from an AC vent) bothers my beam scales more than my digital ones.
 
As I'm sure you know already, the FA digital scale comes with a 50 gram calibration weight, but that's too heavy for the Lee balance scale to weigh. Take a coin (or set of coins) to your local jeweler and ask him to weigh it for you. Then you will have a known weight that the Lee can handle. You may have to promise to buy a 5 carat diamond next week to get them to weigh it, but promises are cheap. ;)
 
A good, calibrated check weight is needed to see which, or if either scale is reading correctly.

Weighing the same object will show if the scales weigh the same. But without being calibrated against a known reference, you won't know what the exact weight is.
 
At this point in time I would trust a beam scale over an inexpensive digital scale. I'm not convenced that the "bugs" have been worked out of the low end digitals (flourescent lights, auto off, clean power necessary, etc.). If I had several thousand $$ to get a Certifiable Lab quality scale, then I'd trust that too, but not over a beam scale. BTW the Lee scale uses a vernier scale for reading/setting weights. I have not had any trouble reading my Lee (I also have a Lyman-Ohaus, and RCBS), mebbe 'cause I used a vernier caliper long before I got a dial caliper...
 
It seems to me that while limited my experience shows that Lee's measures, charge weights, & data have a safety margin built into them. It appears they expect someone to try to push the edge. If this is there plan then there reasoning sounds correct but i would actually like to know where the edge is for myself so I know how far I want to stay away from it. Instead I just use there figures for a ballpark to get me close enough to start my own testing & adjusting. You can get check weights but there is even a small variance in them. The most important thing isn't accuracy but consistency. Pick a measure make sure that it reads the same each time & can detect small changes(I'm OK with 0.1gr). If you load to 4.6gr on one scale & want to use the other just see what the same 4.6gr load weighs on the other & use that measurement.

Say the Lee is 4.6 & it only weighs 4.2 on the digital then charge with 4.6 when using the Lee & only use 4.2 when using the digital.
Quote:
If safety is you goal use the one that reads lower than the other
I think this is backwards.
Click to expand...
I think your right.
 
mdi +1

It could be difficult on the eyes to read, but the mechanics of using it are pretty simple. I also don't see how a beam scale could be off if you zeroed it in properly to begin with. I'd trust the beam scale, but do make sure you zero it in first.
 
Double the load, then measure on both. Then triple the load and measure on both. See if the measurements are consistent and linear.
 
You may also want to make sure you are looking straight across on the beam scale at eye level if you are looking at it at a angle it could give a optical illusion.
 
I also trust the beam scale more. I have weights that were provided for me from a lab, and do not find the time enough to go to a digital scale.
The beam scale if set correctly does not require good eyesight, but just to see it balances.

Now I confess I have never owned a digital scale so I may be all wet, but I never saw a need for one.
Regards,
Jerry
 
First off, thanks to all of you for your response. The digital scale came with a weight for calibration. I calibrate it prior to weighing any powder. Since my post I started over again, paying more attention to weighing the powder. My first weighing was 4.0 on both scales. The 6th weigh on the digital went to 4.2, 9 thru 15, 4.3 while the Lee scale measured 4.0 with each charge. Accuracy for the digital scale is listed as 1/10th grain and it appears that I'm not getting that. I think I might have found the problem. I'm reloading in the basement and the air temp is 54 degrees. The operating temp for the digital is 50-86 degrees. I think the temp is the culprit for the varying degree of accuracy.
 
I use an RCB 750 digital and a Lyman Balance beam as back up 99% of the time they match when not I began rechecking both.

Digitals are super sensitive to wind any vibration, etc,the balance beam can be dusty, off level,etc,many issues with all scales, I've worked with expensive models in labs they also require a great deal of care.

My current setup works great but again require a clean vibration free environment, don't think I would want to reload now without digital scales.:D
 
jmorris wrote: ...If safety is you goal use the one that reads lower than the other...

I think you would want to take the balance that reads HIGHER.

O.P.:
You can not tell which is more right. You would need to at least get a set of check weights. You should get check weights that are more accurate than your balance and not the cheap junk sold by RCBS or Lyman or that weight that came with the balance.

For both, you can plot the "actual" weight (to the accuracy of check weights you are willing to spend money on) vs. the displayed weight. Once you have this plot, the beam balance is "calibrated" and you can simply make the correction shown on the graph. In both cases, you will quickly see that you can't even see the error down in the low pistol charge weight area.

The whole idea of comparing two scales and determining that the new one is no good since it doesn't read the same as the balance you have always trusted shows a failure to think logically.

If someone wants, they should get a Sartorius analytical balance with internal calibration weights and a capability of reading to 0.01 grain.

I still have the Ainsworth digital balance I bought in the early '80s. It, and the next few digital balances I have, have never shown any drift or other problems. If yours drifts, CALL THE MANUFACTURER. You have a bad balance.

I think that the Chinese factory may not be shielding the electronics properly.

PS: the problem with a beam balance is that you won't notice when it goes out of kilter due to dirt, dust, aerosols in the air, rust, dings, etc. Most people keep the beam on the balance at all times and NEVER cover the balance.
 
A cheap test use different weight bullets to cross check your scales, a digital scale can drift as it warms up and drive you up the wall.

Use a large grain rifle powder (4064 - 4350) and count how many grains it takes to move the balance beam scale one reference mark.

"A man with one watch always knows what time it is, a man with two is never sure" good one jmorris ;)

I have seven watches, my computer is hooked up to "time.nist.gov" to synchronize the clock and I have a short wave radio to pick up the atomic clock in Ft Collins Colorado.

I'm not sure what the time really is but my 38 year old balance beam scale when cross checked with bullets has never let me down.

Below Hornady .45 Cal 200 Grain XTP bullet, and cross check with different weight bullets

IMGP7434a.gif

IMGP7436a.gif

Whats the sense of being a bullet head if you don't use it! :D

(Your not in an air condition humidity controlled test lab, and bullet ball park is close enough)

And Mr. oldham, I have chronologically gifted eyesight also, and with the money from my new part time job I'm going to buy new dark glasses. :rolleyes:

blind.gif
 
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My first weighing was 4.0 on both scales. The 6th weigh on the digital went to 4.2, 9 thru 15, 4.3
Click to expand...
Most all digital scales will drift as they warm up to operating temperature after being turned on.

If I was you, I would turn it on at least 1/2 hour before you plan to use it, and then zero it.

Also, make absolutely sure you don't have an air vent blowing on the scale.

They are sensitive enough to detect when the A/C or furnace comes on and blows air on it.

rc
 
My beam scale from RCBS is nowhere near as consistent as my digital. I can drop several grains without the RCBS moving but the dig reads right now. I can remove the powder tray for the beam change the way the powder is laying in it & get a different reading. The dig makes no difference.
 
calibration

That 54F in your reloading room, did you measure that with a calibrated thermostat, an electronic one, or a mercury job?

;)
 
Digital scales do need a warm up to settle on the zero and then need to be zeroed. If yours runs on a battery it could be going bad and that could cause drift as the power depletes as it is used after sitting off for a period of time. Just cause the scale is new does not = a good battery BTW.
 
The reloading room is partitioned from the rest of the basement. There are no vents in the room, hence no drafts. The temperature was recorded with a mercury type. Manufacturer states a 30 second warm up prior to calibrating. As far as a 30 minute warm up, this unit shuts off after two minutes idle. Both scales are on sturdy level surfaces.
I purchased the digital scale with the notion it would be faster measuring powder charges, not with the intention of proving the beam wrong. At this point I'm not looking at the beam scale, but trying to stabilize the digital. I am going to call the company and see if they can help. In the meantime, gentlemen, thank you for all of your support. After I have contacted the company, I will post their reply.
 
No Scale's accuracy can be trusted unless you use check weights to verify.

Beam or Digital, without a check weight set, so the scale's reading can be verified over several different weights, you are only guessing.

Bullets can vary in weight so they don't make reliable check weights.

A scale could be accurate at 200 grains when using a bullet but is it accurate at 5 grains?

A scale could zero just perfectly but is it capable of reading a weight accurately all through the range of loads you use?

Get a set of check weights and be sure. The RCBS set gives one the ability to create check weight groups in .5 gr intervals from .5gr to 65 grains. I use mine by putting check weights on my scale that come closest to the load I will be working with. If it doesn't read exactly what the test weights call for, a cleaning and calibration is in order.

BTW, who carries a watch anymore? For those that do, and want to check the time, just look at your cell phone. Most, if not all, get their time from the NIST clock in Boulder, CO. No more accurate time than that.
 
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