Opinion Re: My Scale And If It's "OK"

[otisrush]

I would appreciate it if folks could weigh in on the following. I'm trying to determine if my scale is behaving like scales should. I'm new to loading (a little over a year) and I don't know what is normal or not in this area.

The scale is an Ohaus 10-10. I bought a bunch of stuff from a friend and all I know is that he had it "for about 20 years" - or something like that. FYI - I've cleaned the stones and knife edges with alcohol. I can't observe anything that seems unusual per se. The scale is sitting on a surface that is level in both dimensions. I've experimented with furnace on and off, as well as lights on and off, and neither of those seem to make any difference.

The two photos below are from 1/ when it was zeroed and 2/ with 50gr of RCBS check weights in the pan. I don't know how good (or not) those check weights are considered to be. Should I expect the pointer to be right on 0?

Two other behaviors I've noticed:
* The beam seems to move less freely if the beam is pushed toward the back of the scale. I think it's binding on the magnet when that happpens. So I tend to check frequently that the beam is pulled forward so it's sitting toward the user's side of the stones.
* When I'm using it if I lightly tap the pan down with my finger (so the indicator moves up), when the pointer settles, it tends to settle on the *high* side of 0. Conversely if I tap the pan up so the pointer moves slightly down then the pointer stops either on 0 or slightly below 0.

Do people read this and think "Get that scale checked out......or just get another scale." or "That's perfectly normal."?

Thanks.

OR

 

[PCCUSNRET]

I have 3 of these scales and two of the return to zero when properly adjusted on a level surface, the 3rd one is off by several grains so I'm using it for parts. For most rifle loads being off by 1 gr. probably wouldn't be a problem, but for many pistol loads 1 gr. might cause you problems. I don't think Ohaus will service these scales since they told me they didn't have parts available for the one I have that is damaged. You might still give them a call to see if they could just calibrate it for you. There was someone on THR that worked on these scales but I moved and lost all my e-mail (and contacts). Sorry I couldn't be of more help.

 

[243winxb]

Set the zero. Then when placing the weight on the scale, the pointer should always be within 3/10 gr. Or less of previous time used. Most scales are only accurate to 1/10 gr +/- I guess normal.

 

[rcmodel]

The beam seems to move less freely if the beam is pushed toward the back of the scale.

Then, don't do that!

Keep the beam knife edges centered between the bearing stop plates.

If one end or the other of the knife edges are rubbing on the plates?

Your scale will do exactly what it is doing.

Nothing should touch anything, except the V's touching the agate bearing blocks.

rc

 

[gamestalker]

^^^ this.

And also make sure the knives aren't bent upward.

Also, if the frame isn't fairly close to level when the scale is zeroed, than you need to either add or subtract some weight from the pan carrier. Other wise, the knives will ride on their sides, instead of on the tips of the pointed edges.

GS

 

[someguy2800]

The most important thing is that it is repeatable. If you put the check weight in the pan 20 times and it always stops in the same place then there is nothing to really worry about. Exact weight of the charge is not really important. You just need to accurately reproduce that weight over and over.

 

[W.E.G.]

Accuracy of your scale is important.

However, the most important thing is the accuracy of your POWDER MEASURE.
This does not get stressed enough.

The usual advice on "working up" a load applies.
Use a reliable reference, and develop a load suitable for your rifle.
Once you have that load - and assuming you have QUALITY POWDER MEASURE - make note of the setting on the powder measure.

Thereafter, when you want to duplicate your "good load," you can set the powder measure to the determined setting, and count on that for good ammo.
The scale's only role at that point is to double-check that you have not committed a gross error in setting the knob on your powder measure.

And be sure to check!

But don't get concerned if your scale shows the weight to be one hash-mark off from where the value you got the last time. If your powder measure is set to the correct setting, you will throw the same volume as last time. Period.

All this is probably little comfort to the "tricklers."

If you are bound-and-determined that trickling powder charges is essential to your success, you will be forever married to the scale, and to the notion that whatever the scale says is the truth, and is the overriding factor to be weighed (pun intended).

Then go to a benchrest match.

The benchrest guys are the ones who are trying to shoot all the bullets into one hole. Many load their ammo AT THE MATCH.

And see how many of the benchrest guys are using scales.

That is all.

 

[MEHavey]

Residual stress (however light) on the bearing point.

1. Cleaning heck out of both bearing/surface contact point. Dry off w/ final Q-Tip.
2. (and this is the important part) As the scale is coming to rest, gently/repeatedly tap your finger on the table next to it to slightly vibrate things into final position

Works all the time, everytime -- fully repeatable readings.

 

[BSA1]

However, the most important thing is the accuracy of your POWDER MEASURE.

I do not measure individual powder throws. Individual powder charges can have unavoidable slight variations in weight. For example powder charge from a full powder measure can weigh more than the same powder from the measure when it is 1/4 full.

I dump 10 powder charges in the pan and weight them in my scale. The weight of 10 charges will tell you about the overall accuracy of your powder measure. For example 10 throws of 14.0 grains is 140.0 grains. Lets say it measures 141.0 grains when I weigh it. So I let someone better a math than me but the 1.0 grain is divided by 10 results in the average individual throw being 14.1 grains. Usually for me the variation is smaller than that. The difference is too small to be measured by a balance beam scale.

In real world shooting that slight variation is meaningless. If you are a benchrest shooter you will be using better reloading tools including the powder measure and scale. With max charges you should be paying more attention to other warning signs of excessive pressure.

 

[243winxb]

The pan support assembly may have a removable piece. It may contain tiny lead shot that is used to balance the scale. A screw holds it together. I dont know if the Ohaus 10-10 has this, some do??

 

[fguffey]

Do people read this and think "Get that scale checked out......or just get another scale." or "That's perfectly normal."?

Thanks.

I believe you are going to have to decide if you want the scale to zero or measure accurately at 50 grains.

F. Guffey

 

[Kaldor]

Is the scale not adjustable to zero it out?

Also, do the lines by the pointer note 100th's of grains?

Id use it as it is.

 

[C.F. Plinker]

My procedure for zeroing a scale is just a little different that what you have done. I start with a level shelf as you did, then I use the leveling wheel on the left end of the base and paper shims under one of the feet on the right end to get the base of the scale level in both directions. Now I hang a clean empty pan on the scale and see if the scale reads zero. If it does all is good. If not, you will need to add or remove weight from the pan support until balance is achieved. Note: on some scales this can be done by moving the adjusting nuts on the end of the beam in or out.

Now put the check weight in the pan and see where it reads. On the picture above the scale was reading about 50.25 grains which is an error of about 1/2 percent. Now tap the pan down a little and see where it settles. Do this 10 times to see if it always settles in the same spot. The amount of variance will give you a good idea of the consistency of your readings.

If it always settles high then it could be that the check weight is a little heavy. Now as mentioned in an earlier post you have to decide whether you want to believe that the check weight is right or that the scale is more correct. I do the former. I put check weights equal to the amount of powder I am weighing into the pan and use the leveling wheel to zero the scale. This way I am always using the check weights as my "standard" for calibration. Since the check weights never leave the loading area the 50 grains I set today is the same as the 50 grains I set last week or last year. Since all my loads were worked up this way they will be just as consistent.

 

[spitballer]

gently/repeatedly tap your finger on the table next to it to slightly vibrate things...

this method very useful for e-scale also

 

[otisrush]

Thanks so much everyone. You've provided some really excellent input. There are times when someone says something and I think "D'Oh! Why didn't I think of that?" (e.g. rcmodel's point to keep the knife edges centered.)

I've done two things and the overall behavior has been improved - although not quite eliminated. I've:
* Removed the bearings and cleaned them really well.
* Experimented with the table-tapping method. It is interesting how you get a little beam movement when that is done.

On the one hand I can appreciate the scenario where, given I'm not trying to be a competition shooter, that this level of issue is likely beyond my shooting ability. On the other hand, it's great to hear from more experienced people in case there is something I don't think is a big deal.....and it turns out to be a really big deal.

Thanks again.

OR

 

[JimKirk]

I see the scale in the last photo reading at most 0.12 to 0.13 grains over(plus) Zero ...

There are Five lines above and Five below Zero ... each of these lines represents 1/10 of a grain .... there are also Three dots below the bottom lines that also show 1/10.

My question is what weight are the check weights certified to ... the cheap weights are not certified very close ... the ones that are .... are expensive ...

Handling check weights can also add finger oils and change the weight ... that is why they come with tweezers to move with.

 

[otisrush]

I see the scale in the last photo reading at most 0.12 to 0.13 grains over(plus) Zero ...

There are Five lines above and Five below Zero ... each of these lines represents 1/10 of a grain .... there are also Three dots below the bottom lines that also show 1/10.

My question is what weight are the check weights certified to ... the cheap weights are not certified very close ... the ones that are .... are expensive ...

Handling check weights can also add finger oils and change the weight ... that is why they come with tweezers to move with.

I'm confident I don't have the expensive check weights. They're the RCBS weights that cost $30-35. They come in two plastic boxes - one box has a 2x20gr and 1x10gr. The other box has a 5gr, I think a 2gr, a couple of 1gr and a 0.5gr. I have no idea what they're certified to. I do use tweezers and do not touch them with my hands.

 

[fguffey]

I have a scale that weighs check weights. I have two sets of check weights that total 86 weights. In the two sets there is a mix of check weights. Some are aluminum, some are stainless and the rest are brass. Of the three metals the brass weights are the least stable/accurate. When checking test weights I am not surprised when I have three different weights for 3 test weights that should weight the came.

When checking gages there is a term called 'wrung', then it goes straight to 'wringing'. When it comes to checking scales I have no problem with wringing test weight.

F. Guffey

 

[JimKirk]

I hope you didn't think that I thought you should have the expensive test weight ... I was only pointing out that they vary some ...

That RCBS 10-10 is a great scale ... I have the 5-10 which is the same except for the base ....

 

[otisrush]

I hope you didn't think that I thought you should have the expensive test weight ... I was only pointing out that they vary some ...

Not at all. I was just trying to be specific about various details that are or might be contributing to this situation.

Thx a lot.

OR

 

[Rancher5]

I have 3 of these scales and two of the return to zero when properly adjusted on a level surface, the 3rd one is off by several grains so I'm using it for parts. For most rifle loads being off by 1 gr. probably wouldn't be a problem, but for many pistol loads 1 gr. might cause you problems. I don't think Ohaus will service these scales since they told me they didn't have parts available for the one I have that is damaged. You might still give them a call to see if they could just calibrate it for you. There was someone on THR that worked on these scales but I moved and lost all my e-mail (and contacts). Sorry I couldn't be of more help.

50gr should 0 out period,you should be able to fine tune scale with weights under the pan or moving the zero,seriously u need other check weights for checking a scale,,I check mine w/ Lyman check weights .2 grains to 50 grains scale should zero at all check points.

 

[Hondo 60]

Accuracy of your scale is important.

+1 If your scale isn't always reading the same thing, take the beam off & wipe it down.
Then wipe the "knife" to make sure all parts are dust & grime free.

1/10th of a grain isn't going to kill you, but I wouldn't reload until I found the cause.

 

[FROGO207]

When I get a "new" used scale I check it over thoroughly.

First I clean knife edges and agate bearings thoroughly as well as thorough wipe down of complete scale with Fantastic or such.

Then I try it for accuracy at zero and several weights to see accuracy as well as repeatability.

If I have problems I remove the bearings and clean the sockets they are in.

I check the knife edge for rust and stone LIGHTLY if needed to remove.

I then check the beam knife edges for square and level using a hand held layout "t" square. If things eyeball out wrong I GENTLY bend them with long nosed pliers.

Then I will put the beam back into the bearing and check the fit of the knife and bearings for complete contact.

Then I tap the scale a bit to settle things in before trying to test for zero and weight accuracy again. If it still bothers I try reversing one or both bearings. Then test again.

When I am happy it is accurate I reattach the bearing keepers and test one final time.

You can add or subtract weight from the bottom of the scale pan to move the adjustment rod to a center location.

I have successfully "fixed" five broken RCBS/Ohaus beam scales with this method. YMMV

 

[otisrush]

I then check the beam knife edges for square and level using a hand held layout "t" square. If things eyeball out wrong I GENTLY bend them with long nosed pliers.

Could you elaborate on this step a little more? What do you mean by a "hand held layout t square"?

Checking knife edges for square and level appears to be the most difficult thing to check - given how the beam itself is constructed. Basically the knife edges are above the lower edge of the beam. So it's not like I can set the knife edges on a flat surface and see if they're horizontal.

Seperately - I had the idea to weigh each check weight individually to see if they all check out. In this thread the 50gr check I did was by placing 2x20gr weights and 10gr weight in the pan. If all three check out to be 20, 20 and 10 respectively then I think I *know* I have an issue with the scale. If one of those three weighs over their marked weight - then it seems I have an indication I have a problem with a check weight.

OR

 

[243winxb]

The most important thing is that it is repeatable.*

Like in the photos.