Help A New Handloader - Scale Issues


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HayseedDixie
December 15, 2006, 11:08 PM
Hi, folks! I've been a member of this board for quite some time, and have visited on many occasions to search for gun related questions. Now, as a beginner in the world of handloading, I've got a question for you fine ladies and gentlemen. I recently purchased my first scale (an RCBS 5-0-2) which, to the best of my knowledge, has worked just fine. It zeros on my bench and gives me quick results. Here's where it gets interesting. I just received a gift of an RCBS 10-10 scale (I don't think the gifter realized I already had a scale). But it's a relatively pricey scale, and I'm not one to look a gifthorse in the mouth. So I thought I'd set them both up and compare and contrast the scales by taking a few measurements. The 250 gr. weight provided with the RCBS 10-10 scale shows to be a few grains too light on the new 10-10 scale. The very same 250 gr. weight, on the 5-0-2 scale (which was perfectly set to zero on my bench and sitting in the same spot as I had the 10-10) shows the 250 gr. weight to be a few grains too heavy. As I tried a few bullet and powder measurements, I got consistent results. The 10-10 scale shows objects to be light, the 5-0-2, too heavy. I'm baffled. Could I have possibly gotten two screwy scales right out of the box? As I've stated, the scales zero perfectly. Any ideas as to why these two scales give two consistently different results? Thanks to any and all!

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Jake in TX
December 15, 2006, 11:18 PM
I think it's time to contact RCBS.

Jake in TX

Steve C
December 16, 2006, 12:11 AM
One thing to remember is that a powder scale is only accurate to 0.1 gr so a .2 gr difference would be within the extreems of their accuracy.

First thing would be to set both scales on your bench and set them to zero becaue it sounds like you put the scales on and off the bench between measurements. Make sure the scales are free from dust and other debis especially the balance knife edges. Then check the differences between the scales by using different objects that you first measure on one then then immediately measure on the other. Differences should be in the 1/10th grain, not several or even one full grain. Start with light objects like a penny or dime rather than a weight that is at the extreem of the scales capacity. Write down your results.

If there's still significant difference between the scales take that penny, put it in container where it will not get touched and have it weighed on a more accurate standardized scale. You could ask your pharmasist to weight it on his scale. There may be some conversion frm grams to grains, you can use this website for Measurement Conversion (http://hemsidor.torget.se/users/b/bohjohan/convert/conv_e.htm) This should give you a measurement from a scale that's been standardized. If you have access to a scientific scale like in a laboratory then that would work too. Compare your weights to the standardized scale to find which one of your scales is closer to being accurate.

Too far off, then contact RCBS.

HayseedDixie
December 16, 2006, 12:45 AM
Thanks Steve! That's just the sort of information I was looking for. Maybe now I can get this sorted out.

dcloco
December 16, 2006, 01:12 AM
The 502 and 10/10 scales have lead pellets (or similar) in the holder for the pan. These are used to zero the scale.

Using the 250 grain checkweight is a bit much. Might try something along the lines of a 50, 100, 150 range (such as a bullet - use the same bullet on each scale and see what they weigh).

As the weight increases, whatever the difference in the scales is magnified.

These are just beam scales.

Also, the magnetic dampening might not be centered....in either scale.

I use a Hornady/Pacific beam scale - because the beam is the longest that I have seen. Longer beam, finer balance measurement.

nelson133
December 16, 2006, 05:44 AM
The most common (and most important) use for a scale for a sclae is to check powder charges. These are way less than 250 grains. You can get the Lyman check weights set to test your scales. They have worked well with mine.

loadedround
December 16, 2006, 09:54 AM
Hayseed: Being a retired chemcal engineer, one of the most important things I learned about about a balance(scale) is repeatibility or sometimes called reproducibility. I would suggest you take 2 or 3 small coins like a nickel or dime(not quite so heavy as a 250g weight) and weigh each coin 10 times removing it from the pan each time. Record your results for each coin and the balance with the closest average weight should be your most accurate one. Reloading balances usuall have an accuracy of .02 gr regardless of mfgr. advertizing. I reallize you now have two balances, but the easy way to go is with an electronic balance for around 100 bucks like the Dillon, Pact or RCBS(made by Pact). Once you use one, you will never go back to an old fashioned beam scale. JMHO

Walkalong
December 16, 2006, 10:21 AM
called reproducibility

Amen!! This will drive you NUTS if you do not have a good scale, regardless of brand or type.

redneck2
December 16, 2006, 10:24 AM
If you have one clock, you always know the time.

If you have two clocks, you're never sure what time it really is.

The Bushmaster
December 16, 2006, 10:49 AM
I have both the RCBS 5-0-5 and electronic scale. They both indicate the same weight (as close as one can visualize). I use the 5-0-5, on occasion, to check the electronic. It insures that the electronic hasn't gone off and re-inforces my confidence in the electronic. It doesn't hurt to have both. Besides you might damage (heaven forbid) one in the middle of reloading and isn't it nice to have a backup?:D

PsychoKnight
December 16, 2006, 10:51 AM
I've owned several reloading scales - kept buying because weight checks never come out right. After zeroing, I expect a semi-certified 100gr weight to clock in at 100gr. Never did work that way.

But here's a work around for the majority of scale uses, which is weighing powder charges.

I reset the beam to the mark not at zero, but as close as possible to the weight I am seeking. So if I want to make sure my measure is throwing 12.8 grains, I place 12.8 gr worth of check weights into the pan, move each poise indicator to position for that weight, then center the beam. You don't need to have the exact same weight between your desired charge and your combination of check weights. If the closest check weight combination I can create is 12.5, even tho my target is 12.8, just move the indicators temporarily for 12.5, center the beam, remove check weights, then weigh the powder in the normal fashion.

When I do it this way, all my scales showed the same results. Instead of asking for accuracy across 500 or 1000 grains of weight, you are narrowing the calibration for use within a very limited range.

Having two sets of the Lyman Deluxe Scale Check weights will give you enough pieces to allow you to center your beam to just about any possible weight within the combined maximum. Using two check sets to center the beam for a particular weight, you don't ever have to use an approximation.

RecoilRob
December 16, 2006, 11:27 AM
Your 250grn measurements are within 1%, and I'd wager that is all RCBS expects from the scales. After all, they are not Lab Grade or Certified.

1% deviation in normal powder charges, even really large ones, isn't enough to cause much of a problem and if it is, you are WAY too close to the Redline!

I have used a 10-10 for over 20 years and it is a great piece of equipment. It WAS a tiny bit off when checking with the weights....so I adjusted it. If you have some very fine shot (7 1/2's or so) you can spend some time playing with the counter-balance weight in the pan holder and get things spot on.

It would take a lot longer to get things exactly right at the factory and I'm sure they stop tinkering once the +/- 1% is reached. If it bothers you, adjust them! Not hard at all.

Walkalong
December 16, 2006, 11:28 AM
Being a retired chemcal engineer, one of the most important things I learned about about a balance(scale) is repeatibility or sometimes called reproducibility. I would suggest you take 2 or 3 small coins like a nickel or dime(not quite so heavy as a 250g weight) and weigh each coin 10 times removing it from the pan each time. Record your results for each coin and the balance with the closest average weight should be your most accurate one. Reloading balances usuall have an accuracy of .02 gr regardless of mfgr. advertizing.

If you have one clock, you always know the time.

If you have two clocks, you're never sure what time it really is.

Repeatibility is what was driving me NUTS.

I finally decided that after finding a load that shoots real well, I don't worry if it was 5.1 or really 5.2 or even 5.0. I just keep setting my Reding 10X measure to whatever setting gave those results. I carefully wieght a lot of powder on my RCBS and or Pact BBK and chart them on an Excel spreadsheet I made up. Depending on the powder I wiegh and chart settings for a range of wieghts for that powder. (might be 4.0 to 8.5, or maybe 6.0 to 9.0, etc.).
For Universal Clays I wieghed charges from 5.4 to 6.8 - with AA # 2 I wieghed charges from 5.1 to 6.4. I log all the 10X settings for these wieghts and go by the settings for loading. When I find a load I like, (such as 6.3 Grs. AA#2 and a Berry's 185 Gr. SWC in .45ACP) I don't need to worry if it is exactly 6.3 as long as it shoots good and is within safe limits with no pressure signs. When I find one I really like it is time to buy a good quantity of that powder and recheck my settings for that lot. I had two different 1 lb. containers of Universal Clays that wieghed exactly the same and they were 4 years apart.(wow, not the norm) I bought a 4 lb.der last gun show , but have not checked wieghts on it yet. Variations in day to day readings and differences from scale to scale are things we just have to live with I guess. I have thought about buying a different, supposedly more precise digital scale, but I wonder if it will make any real difference? I put a link to the two scales I am considering. Does anybody with knowledge of digital scales know about these scales or have recommendations? Thanks.:)

http://www.toplinedigitalscales.com/catalog.php?action=124&item_id=229

http://www.toplinedigitalscales.com/catalog.php?action=124&item_id=236


CSI Series - Model CB & AWS Series - Model 30PR

Walkalong
December 16, 2006, 12:58 PM
Just wiegehd out some charges from the 4 lb. batch of Universal. After FINALLY getting the PACT to settle down I got exact readings from the old batch on 6 of 7 tried. Stopped there. Hmm...... maybe I should just keep the PACT.
BUT, It just takes forever to settle down and if anything changes , temp, A/C cuts on/off, heat cuts on/off, I move my hand by it, it freaks out and you have to wait for it to settle down or re zero and sometimes recalibrate!!!!!!!!!
Is this just normal for electronic scales or do the more exspensive ones do better?

Jim Watson
December 16, 2006, 01:52 PM
I dunno, I just leave my PACT on unless I am going to be out of the shop for a week or more.

I have gone back to the balance beam scale for trickling target rifle powder charges to the desired weight. You can watch the beam move as you twirl the trickler. A digital just Snaps! to the next number and you can overshoot. You will likely overshoot anyhow, there is enough lag in the setup to cause it. I can trickle a load to 25.0 gr indicated, lift the pan and set it back down and get a reading of 25.1 or even 25.2. Does that matter? Probably not, but it is kind of aggravating. So I watch the old Lyman beam swing.

highlander 5
December 16, 2006, 02:16 PM
I stopped using a balance beam years ago and now use a Dillon electronic scale. Those nice big number on the Dillon are so much easier to read than the hash marks on the balance scale.

TooTaxed
December 16, 2006, 08:23 PM
Setting any beam scale to its zero and then setting it to your desired weight does not mean that your weight measurements are really accurate. Very slight variations in the weight shift notches cut into your beam will lead to slight inaccuracies from true weight.

The only way to approach true accuracy is to calibrate your beam scale with a true check weight CLOSE TO THE WEIGHT YOU WANT! I.E., if you want to weigh 8.5 grains of powder to set a drum measure or load some test loads, you should put a known 8 grain weight on your scale and adjust your scale to read that, then set your scale for 8.5 grains. RCBS (among others) sells a set of calibration weights in 1,2,3,5, 10, 20 grain weights...you can use one or any combination of them to approximate any common weight.

Frankly, NO scale...beam or electronic...can be trusted unless it is frequently calibrated with true weights. Assuming that any scale, even an expensive electronic, is giving you accurate loads without calibration...is merely an assumption.:eek:

Liberty4Ever
December 16, 2006, 11:19 PM
Digital scales are becoming very good and very inexpensive. I've bought three different types of portable electronic scales on eBay. My favorite for reloading is a NEVA brand I just bought. The buttons are nice and have a positive click to them, unlike some cheap membrane buttons. The scale resolution is .1 grains and the capacity is 100 grams (1543 grains). It zeros on startup and it ships with two 50 gram calibration weights. I check the calibration often.

Maybe not as nice as one of the much more expensive powder scales, but the accuracy is good and the usability is good too. I like the fact that it uses two AAA batteries so it doesn't need AC power.

I use a scale a lot when developing loads, and a good scale is important. The NEVA is an import, but the quality is good and it seems very accurate, reliable and repeatable. It was $22 dellivered, which is a pretty good deal.

I kept my Lee Safety Scale. It's very accurate and fairly foolproof, but it's slower than Christmas. I cross check critical weights on the Lee balance beam scale. They always match.

I wouldn't tolerate scales that weigh high or low. You should be able to calibrate the scale and it should be accurate and repeatable.

Rico567
December 17, 2006, 08:21 AM
I will preface any comments about scales by stating that the pursuit of extreme accuracy using the combination of traditional scales / powder measures is pretty well doomed to failure. The answer for me turned out to be the RCBS (PACT) digital powder dispenser / scale. When I want dead-on accuracy, it delivers. The price that is paid (apart from the purchase of the equipment) is the added calibration / setup time.

I agree with all that's been said about reference weights for scales. The RCBS (PACT) scale that pairs up through an infrared link with the dispenser comes with two check weights, a 20 gram and a 50 gram, and there is a fairly quick calibration sequence for the scale, the longest time being a prescribed 20 minute warmup. If I use my older balance beam scale (an Ohaus 10-10, pretty much identical to the current RCBS 10-10), which I rarely do these days, I can calibrate it using the electronic as a reference, once the latter is calibrated using the check weights.

I have never had any reason to suspect errors stemming from my scales. I should note that I reload in a basement that has NO air vents or any other source of drafts nearby. I believe that these are the primary source of frustration for many people I've read about on forums like this who are experiencing problems with scales, particularly of the balance beam variety. My weighing is also done on a VERY heavy carpenter's workbench, with a solid wood top about 2" thick and an iron frame. All this contributes to the stability that is a prerequisite for using scales. On the other hand, I don't believe that accuracy with this level of equipment can go further than .1 grain, nor is it necessary given what I reload.

griz
December 17, 2006, 09:24 AM
Not sure if the RCBS scales have this option, but some allow you to level the scale independantly from the zero. But if you have them on the same bench they should both at least be level to each other.

308win
December 17, 2006, 10:59 AM
You should level the surface on which you are placing your scale and level in both planes. The leveling adjustment on your scale only levels on one plane (fore/aft). I have three scales (2 RCBS 5-10, 1 OHaus not sure of model but old) and they all weigh with in .1gr of each other on a leveled surface.

If you enjoyed reading about "Help A New Handloader - Scale Issues" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!