Accuracy of balance scales

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a__l__a__n

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I have a couple of old (maybe 50 years old) Ohaus scales: a 5-0-5 and a 10-10. They don't agree on light loads. The discrepancy is about 0.1 grain for weights around 4 grains, with the 10-10 giving the lower reading. The discrepancy is consistent and repeatable, even after moving and re-zeroing both scales.

I can remove and replace the pan 10x on the 5-0-5 and it returns to zero every time. The 10-10 does *almost* the same thing, but there are occasionally very small deviations from zero (a fraction of a tick mark). But these deviations are much smaller than the difference in the weights in the 4 grain range.

So I trust the 5-0-5 more than the 10-10. But I'd like to know what a charge *really* weighs, and to know that a 4.0 grain charge I weighed today is the same as a 4.0 grain charge I weighed a month ago.

Is there some recommended maintenance that I'm neglecting on these scales? I'm reluctant to apply any oils or cleaning solutions. Maybe alcohol on a Q-tip would be ok... What would you do?
 
I have a 50+ year old set of OHAUS 5-0-5 scales that may or may not do the same thing. Cleaned the pivot points with auto Carb cleaner on a Q-tip and applied a touch of silicone with a Q-tip. Then I bought a small set of digital scales for less than $50 and answered all my weighing questions. Old scales are fine for what I do, digital scales are great for weighing bullets and finding the internal capacity of cases with water from batch to batch. I just plink every now and then.......
 
I JUST had the same problem! My 10-10 scale was showing different grain weights trying to load 11 grains of unique for my marlin 44 mag
 
I try for loads in a range that can tolerate +/- 1 grain on the powder dropper / measure, and with some room for variation in the case volume, the OAL, etc... Variation in the scale is in addition to all those other variables. At some point all those added together could matter. I think I'll try a Q-tip with some alcohol on the contact points.
 
Ever thought of using lens wipes to clean the contact points and to keep the beam clean? On some race ignitions I use them to clean crank trigger pick-up ends and the rare earth magnets used in their production. Cheap cleaners that will not damage anything.
 
a__l__a__n said:
I think I'll try a Q-tip with some alcohol on the contact points.
Click to expand...

I bet that will solve your problem. Alcohol on a Q-Tip is all I've ever used on my 5-0-5, and it's almost as old as yours. While you have the beam off the scale, use a magnifier to check for burrs or other damage to the pivots.

Tim
 
Do you have a set of weights? Not just the calibration weight, but a set with various smaller weights?

As stated above good, CAREFUL, cleaning is in order.
 
PWC said:
Do you have a set of weights? Not just the calibration weight, but a set with various smaller weights?

As stated above good, CAREFUL, cleaning is in order.
Click to expand...

Agreed - The very first thing to do is buy a basic set of grain checkweights, anything other than, that your are starting off with a guess. A set or RCBS or Lyman checkweights is around $35 and will last a lifetime and give you confidence that your scales are "or not" performing as they should do.
 
Rust on the knife edges, gunk on the agate gem stones, and dust accumulation is the only issues I ever experienced. I use a very light coating of Imperial sizing lube on the knives now with good results. The box on my 5-0-5 has the date of 1973.
 
My mantra has always been - don't damage the agates or the knives, and my antique 505 has treated me very well. The 1010 is still in the bottom of the bottom of the safe, just because for some reason I don't like it. And as posted, the RCBS check weight can easily be one of the most important tools in your reloading arsenal.
 
Ok, RCBS check weight set on order. Exactly what I was hoping to find!

I've dragged the knife edges ever so lightly and carefully across an Arkansas stone for just a couple of inches, and cleaned the knife edges and agates with alcohol. It does seem to have helped - the two scales seem to be reading the same right now. I'll keep a careful eye on it. The check weights will give me a lot more confidence. Thanks for the help!
 
The accuracy of a beam scale is the care they cut the notches/stops on the beam. Everything else is tweakable. Your Ohaus is cut well. Dont sweat it!
 
BTW I also prefer the 5-0-5. It's just a lot easier to verify the zero on that one without disturbing the base, as well as being easier to set the target weight, and also easier to measure the unknown weight of an object (as opposed to setting the intended weight of a charge).
 
Member 1066 has several scale tune up threads on this site. A search of his posts with 1010 as a filter will be a big help. As mentioned if the agate stones and knife edges are not bent or rusty/pitted most times cleaning restores like new performance.
 
I prefer my 5-10; better IMO than the 505; use some check weights (if you haven't already) to determine what it is truly saying for weight. I prefer these over any cheap chinese electronic POS that never lasts more than a month, needs to warm up; is affected by temp changes, etc.
 
I also have a Ohaus 505 and a 1010 that are about as old as yours and the 505 is slightly more accurate than the 1010.
 
What I did was bought a digital scale and a set of check weights. I feel like I am accurate and precise now and it is fast enough to make more weight checks. If you are going to use the beam balance get a check weight or 2.
 
I switched to a digital scale I think it was about 35$ from Academy. I noticed the same thing with my beam scales. I think unless you are matching every bullet neck diameter and case I doubt you would notice the difference unless the scale is seriously wrong. The digital ones take up a lot less room. One thing I strongly suggest is getting either a brick or a slab of polished marble to set the scale on to zero it that way you know it will not get bumped slightly and change.
 
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