Beam scale predicament question

[Texas10]

After reading the posts on this thread, and several other like threads on this site, I had a good look at my recently purchased but little used scale.
I dressed the knives with a diamond hone, blew off the agate beds, and dusted them with moly, checked clearance to the copper damper, set it back up and.......it was still sticking.

Close examination revealed that the aluminum plate with the fixed reference line that the pointer points to was bent inward, probably in an effort to eliminate parallax, and it just touched against the pointer on the beam.
I adjusted it out a bit and presto....works beautifully.

So that was the issue, pointer dragging on the aluminum plate when the beam came up to level as I charged the pan. It'd stick, I would overfill the pan by a few kernels, and then it would break loose and travel up after a few seconds.

 

[group therapy]

It seems to me that if I spent money to have a scale accurized by somebody and it didn't work as expected, I'd go back to that guy and ask him what to do. I sure as heck wouldn't be trying to fix it myself, if I could do that then why would I pay somebody else in the first place.

yuup!!! Scott stands behind his work!!

 

[Webster]

I’m trying to diagnose a beam scale issue I’m having. Want to see if anybody else has ever had the issue. I have a SP tuned Ohaus m5. Dropping one kernel of h4350 the beam slightly moves as expected. So sensitivity wise it is fine. But here is the problem I noticed. I’ll zero it out and test it with the weight. Scale is at dead zero when I start using it. However 10 or so loads in, I’ll recheck zero which I guess you would not think is necessary on beam scale. And the beam settles at 1/10 or more over or under. I don’t understand how this is happening. Could something be getting hung up with the blades or something?

Thanks

I know they say not to put oil on the bearing that the knife edge sits in, but I do it. It makes sense to reduce the friction. The beam seems to move a little better. All of us know how to keep things clean.

 

[Shooter13]

Have you ever set zero, take the pan off then sit the pan back on in a different position and see if it zeros? I have seen them have a "new" zero.

 

[Joe Maisto]

I’m trying to diagnose a beam scale issue I’m having. Want to see if anybody else has ever had the issue. I have a SP tuned Ohaus m5. Dropping one kernel of h4350 the beam slightly moves as expected. So sensitivity wise it is fine. But here is the problem I noticed. I’ll zero it out and test it with the weight. Scale is at dead zero when I start using it. However 10 or so loads in, I’ll recheck zero which I guess you would not think is necessary on beam scale. And the beam settles at 1/10 or more over or under. I don’t understand how this is happening. Could something be getting hung up with the blades or something?

Thanks

I hope I do not ruin your day with this, but I know of no one in Group BR that uses a beam scale. I had one as well, but found there were too many variables, so went to a digital. Been happy with all results.

 

[JFrank]

I do

 

[sparker]

I hope I do not ruin your day with this, but I know of no one in Group BR that uses a beam scale. I had one as well, but found there were too many variables, so went to a digital. Been happy with all results.

hmm, there’s this guy, Bob Pastor....

 

[bozo699]

hmm, there’s this guy, Bob Pastor....

That’s funny right there!...
Wayne

 

[brokeasajoke]

Scale Instructions:

Use the check weight value to set the level of the scale. After moving the main poise, depress the pan with your finger and let the beam swing a few times. This allows the washer on the right side of the poise to find the bottom of the V-notch. Throw charges about 1/2 grain light and trickle up each time. This will yield the most consistent charges.

Scott

@sparker So never zero the scale empty but use your supplied check weight? I didn't receive instructions with mine. Thanks.

 

[sparker]

You can. My reasoning for using the check weight is this: if you establish the level down scale on the beam, any error will get smaller and smaller as one moves the main poise back towards zero. Conversely, if the zero is off angularly, any error will get larger as the main poise is moved away from zero.

Reddings are a prime example of this. Reddings have good linearity for the first ~150 grains. After that, they read heavy by about 1/10th of a grain for every 100 grains beyond that.

 

[Texas10]

You can. My reasoning for using the check weight is this: if you establish the level down scale on the beam, any error will get smaller and smaller as one moves the main poise back towards zero. Conversely, if the zero is off angularly, any error will get larger as the main poise is moved away from zero.

Reddings are a prime example of this. Reddings have good linearity for the first ~150 grains. After that, they read heavy by about 1/10th of a grain for every 100 grains beyond that.

How would you correct for this error? Adjust the leveling screw with the check weight in place?

 

[243Mendoza]

I hope I do not ruin your day with this, but I know of no one in Group BR that uses a beam scale. I had one as well, but found there were too many variables, so went to a digital. Been happy with all results.

Talk about too many variables...I suspect that digital scales have their own set of variables that need voodoo skills.

 

[6BRinNZ]

I have a SP tuned scale from years ago and it is really good. I do think brushing the edges of the knives with pencil lead helped things as it aged.
I used to get hung up on what the op is seeing but after buying a FX120i as a check scale I'm not worried anymore.
To be really certain of its (beam scale) consistency I bought an FX120i. I weigh and trickle up on the beam scale and then check weigh on the FX120i.
The beam scale to a granule is spot on. ~1 in 20 cases I catch an extra 2 kernels.
TBH the price difference between the FX120i and the SP beam scale is not worth it but I now like the fact that everything is check weighed.
My ES/SD is a little lower since I am catching the outliers but my results and x count don't show it.

 

[JFrank]

Sometimes I think these old scales have a sole…
I have a Ohaus 10-05 ( same as M-5) that I’ve tuned a few years ago to a very high level of sensitivity BUT for what ever reason this scale can be a total Diva around the zero V groove, every once in awhile I’ll set it up just to remind myself that Bitches be Crazy…

 

[DirtySteve]

The thing about digital scales is they would give no sign or indication they were off. I like seeing things are working correctly. You can see when a scales beam is hanging up as you trickle. You can not see an electronics problem in a digital.. Just my opinion and it is worth what you paid for it..

 

[1066]

Two little problems that regularly get overlooked with these simple scales:

Almost all these scales use a stirrup to hang the pan assembly on. The stirrup swings on its own tiny knife edges, these knife edges are recessed in a machined groove. If everything is working as it should, the stirrup should be free to swing in the center of the groove without rubbing on the sides. These little knife edges also need to be kept clean and free from dust. I usually give them a scrub with a soft brass brush.
If you remove the pan assembly and give the stirrup a poke it should swing quite freely for a good few seconds.

Another area on RCBS scales that can cause these tiny errors are the points of the knife edge touching the bearing end plates. In a perfect world, the point at the tip of the edge should be in alignment with the edge, therefore, if the tip touches the endplate, as the beam moves it should rotate round around and pivot on a fixed point with very little friction. If the tip point is not exactly in line with the edge, the tip point scribes an arc on the endplate and will never reliably zero.

A further point is that with something like a Redding #2, it has fixed bearing with endplates and the beam pivots around a fixed point with very little tip friction - on RCBS scales (and all other floating bearing types)
the bearings wobble about to self-align with the knife edge - the down side of this that the tip is also wobbling about and no longer rotating on a fixed point.
It's not really practical to center up the beam every time so the tips are not touching, but to see if this is an area where you are having a problem, just remove the endplates and test the scale again with the plates removed.

Some scales like the Hornady/Pacific old "M" type and the newer budget Hornady scale use a specially shaped knife edge to get around this problem

 

[Will Henry]

I ditched the magnets on any of mine with magnetic damping, and just read them on the swing. WH

 

[PracticalTactical]

Years ago I had a Sartorius 2442 like this pictured below. It was a gift from a University Professor I used to shoot with.

For all the complexity and engineering, it could hold accuracy levels people seem to be expecting in this thread.

You guys need to be realistic about the accuracy expectations of single beam scales.

Since the old days I graduated to a Sartorius digital balance that weighed in increments of 0.02 grains, then I upgraded to a Vibra HT220 balance that increments in 0.002 grains.

So, having considerable experience on this subject and with the capacity to weigh very precisely, I have evaluated the performance of several beam scales and I can assure you that accuracy of a beam scale that is within 1/10th of a grain would exceed my wildest expectations... and I have never seen such a thing.

The German engineered scale below might on a good day, but it was fuuusssssyyyy.

There's alot of trash talk here about digital scales but in all cases you get what you pay for. All digital scales are not junk, but there is alot of junk in the price range most shooters are willing to consider.

Once you get into $1500 and up, you are getting a very reliable balance, especially when it has internal calibration like mine. Its a fantastic experience that I hope some of you one day can enjoy.

 

[ebb]

Turn off the ceiling fan when using the scale.

 

[DLT]

Years ago I had a Sartorius 2442 like this pictured below. It was a gift from a University Professor I used to shoot with.

For all the complexity and engineering, it could hold accuracy levels people seem to be expecting in this thread.

You guys need to be realistic about the accuracy expectations of single beam scales.

Since the old days I graduated to a Sartorius digital balance that weighed in increments of 0.02 grains, then I upgraded to a Vibra HT220 balance that increments in 0.002 grains.

So, having considerable experience on this subject and with the capacity to weigh very precisely, I have evaluated the performance of several beam scales and I can assure you that accuracy of a beam scale that is within 1/10th of a grain would exceed my wildest expectations... and I have never seen such a thing.

The Germain engineered scale below might on a good day, but it was fuuusssssyyyy.

There's alot of trash talk here about digital scales but in all cases you get what you pay for. All digital scales are not junk, but there is alot of junk in the price range most shooters are willing to consider.

Once you get into $1500 and up, you are getting a very reliable balance, especially when it has internal calibration like mine. Its a fantastic experience that I hope some of you one day can enjoy.

View attachment 1378548

Must be nice is all I can come up with