Accurize a balance beam scale?
- Thread starter DSM
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jackie schmidt
New member
The only thing keeping any balance beam from being more sensitive is friction. In fact, it is sensitive to a single grain of powder, you just can't detect it.
The knife edges that these small scales ride on offer about as small of a contact area as you can have. But, there is friction envolved. If one grain of powder will not overcome that friction, then you cannot weigh any closer.
Check the knife edges, and see if they have become rounded or blunted. You can restore them by carefully sharpenning them with a wet-stone.
Also, clean the adutments that the knife edges sit in, use a electric contact spray cleaner, something that leaves no residue. Clean is the key here.
There are sufaces that are virtually friction free. For instance, the Mount Polamar Telescope weighs over a hundred tons. It you disconnect the gearing mechanism, a person can move it by hand because it rides, or actually floats, on a true film of oil, supplied by a presurized oiling system............jackie
Just curious. With 133, it takes about five or six of those irregular grains to make a tenth. What's the obsession with a single kernal of powder?
The knife edges that these small scales ride on offer about as small of a contact area as you can have. But, there is friction envolved. If one grain of powder will not overcome that friction, then you cannot weigh any closer.
Check the knife edges, and see if they have become rounded or blunted. You can restore them by carefully sharpenning them with a wet-stone.
Also, clean the adutments that the knife edges sit in, use a electric contact spray cleaner, something that leaves no residue. Clean is the key here.
There are sufaces that are virtually friction free. For instance, the Mount Polamar Telescope weighs over a hundred tons. It you disconnect the gearing mechanism, a person can move it by hand because it rides, or actually floats, on a true film of oil, supplied by a presurized oiling system............jackie
Just curious. With 133, it takes about five or six of those irregular grains to make a tenth. What's the obsession with a single kernal of powder?
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TomD
e publius unum
No way, the theoretical deflection (movement) of a balance scale given a change of weight will be a mathematically determined amount given the ratios of the weight change vs the mass and dimension of the scale. Actually, that's how a balance scale works. So if it were possible to "accurize" a balance scale to give greater deflection to a given weight, it would no longer be calibrated.
M
mks
Guest
Given that the deflection that we want to measure is small, one approach would be to magnify the pointer, so that we can see smaller deflections. Seems like someone showed a picture of such a system on this forum. Just a magnifying glass in front of the pointer.
Cheers,
Keith
Boyd Allen
Active member
I have improved the performance of my RCBS 10-10 by tuning it up. It is a bit complicated, and I will not try to go into all of it here, but I will tell you that touching up the main knife edges, so that there are no shiny spots when viewed straight on, is a great help. Another issue is whether the scale is level, when zeroed. There is a highpower shooter in Bakersfield, that has been mentioned on accurateshooter.com who tunes up scales. After doing some work on mine, I have spoken to him, and believe that he is the best for this job. Evidently, he has done over 300. Also, I believe that when someone is talking about single grain (particle) sensitivity, that he is referring to increasing sensitivity, not the amount of deflection per unit of weight. In other words, changing the scale so that it takes less to make it move. This can be done.
M
mike in co
Guest
i think people have become misinformed in the quest for accuracy.
at this time in our sport, my opinion, is that 0.1 of a grain is accetable accuracy. the problem is that most scales on the market are .1 plus or minus .1...so in fact two charges can be 29.0 and 29.2 and come off the same scale as 29.1. this is what i consider unacceptable. some of us have gone to electronic lab scales to get to the .1 plus or minus .03 or less. this means our loads are 29.13 to 29.07.....significantly closer that plus or minus .1.
i do not need scale that indicates a single grain of n133 nor of 8208, but if i am shooting a large kernel powder like 4895, varget, 4831,,,,,the scale will likely indicate a single grain.
so party A hears that party B is loading to single kernel, and ASSUMES that he too must be able to load to single kernel......WRONG.
party B is a 600/1000 shooter, loading large kernel and thus will see single kernel changes: party A is a short range ppc shooter, shooting n133 and has no need to see single kernel changes. what they BOTH need is to be able to load at 0.1 with something less than plus or minus 0.1.
so we all need accuracy of 0.1, we all need sesitivity better than plus or minus 0.1. we all do not need to see single kernel movement.
getting down from his soap box,
mike in co
at this time in our sport, my opinion, is that 0.1 of a grain is accetable accuracy. the problem is that most scales on the market are .1 plus or minus .1...so in fact two charges can be 29.0 and 29.2 and come off the same scale as 29.1. this is what i consider unacceptable. some of us have gone to electronic lab scales to get to the .1 plus or minus .03 or less. this means our loads are 29.13 to 29.07.....significantly closer that plus or minus .1.
i do not need scale that indicates a single grain of n133 nor of 8208, but if i am shooting a large kernel powder like 4895, varget, 4831,,,,,the scale will likely indicate a single grain.
so party A hears that party B is loading to single kernel, and ASSUMES that he too must be able to load to single kernel......WRONG.
party B is a 600/1000 shooter, loading large kernel and thus will see single kernel changes: party A is a short range ppc shooter, shooting n133 and has no need to see single kernel changes. what they BOTH need is to be able to load at 0.1 with something less than plus or minus 0.1.
so we all need accuracy of 0.1, we all need sesitivity better than plus or minus 0.1. we all do not need to see single kernel movement.
getting down from his soap box,
mike in co
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Boyd Allen
Active member
To clarify, my particular scale had gotten to the point where it's repeatability (with the same weight) was not satisfactory (Yes, I had sent it back to the factory once.), so I felt that I had little to loose by trying to make it work better....which I did. I would not claim that it is now perfect. I am still working on that. As it turns out, the area that seems to be causing the remaining issues, is the little wire hanger that connects the beam to the pan holder. Very slight changes in its position seem to be the problem. If I orient it for each weighing, the problem goes away. I am amazed that a relatively inexpensive scale, marketed for reloading, can be worked over so as to perform as well as some that I have seen. Do I worry about single particles of powder enlarging my groups...absolutely not, but then I have never shot 600 or 1,000 yard matches, or worried too much about ES or SD for short range (1-200 yd.) work.
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4
4Mesh
Guest
And you say this stuff with a straight face? This is a competition forum, not woodchuck hunting. Now, if I guy wants to make his balance beam scale work as well as it can, and would like it to resolve down to nothing, what is wrong with that. Do you think that weighing closer is going to make the groups worse? Ok then, what's the problem?
Furthermore, you are so far off base with these statements it's ridiculous I think everyone here is capable of determining what resolution they require for accuracy, and, with any luck, they're ignoring you.
The reason I want to get my scale as accurately as possible is to test and compare my 1K loads to see what works better, the balance beam or the chargemaster. I'm not really obsessed with one kernel sensitivity, but want it as accurate as possible. I keep getting a flyer that opens a 2" group to 6". I know this can be many other things, but this thread is about scales, not mysterious flyers at 1 k.
Boyd Allen
Active member
Suggestion:
Shoot over a chronograph until you get one of those fliers. If it is powder charge variation that is the problem, I would think that this would show up as a velocity difference. Of course there could be another cause, like variance in neck tension, that would also cause a velocity difference, but it would be a place to start your investigation.
Shoot over a chronograph until you get one of those fliers. If it is powder charge variation that is the problem, I would think that this would show up as a velocity difference. Of course there could be another cause, like variance in neck tension, that would also cause a velocity difference, but it would be a place to start your investigation.
M
mike in co
Guest
i think you are stuck......both of those scales are plus or minus .1...see my earlier post.
if you rework your beam scale, you may get better, and probably good enough for 1000 yds.
the chargemaster is always plus or minus .1....so not good in my opinion.
get a real scale.....something plus or minus .02 or less if you really want to take powder weight out of the equation.
again when long range with a large kernel powder you may get the beam modified enough to work at 1000yds.....add a pointer, and a fine scale for the pointer, clean up the knife edge, clean everything.
and shoot all shots over a chronograph....all else is guessing.
mike in co
if you rework your beam scale, you may get better, and probably good enough for 1000 yds.
the chargemaster is always plus or minus .1....so not good in my opinion.
get a real scale.....something plus or minus .02 or less if you really want to take powder weight out of the equation.
again when long range with a large kernel powder you may get the beam modified enough to work at 1000yds.....add a pointer, and a fine scale for the pointer, clean up the knife edge, clean everything.
and shoot all shots over a chronograph....all else is guessing.
mike in co
jackie schmidt
New member
I tested a Chargemaster against my Denver Instruments TP-153, and +- .1 is being generous.
It seemed that the less "trickling" the Chargemaster did, the more consistant.......jackie
It seemed that the less "trickling" the Chargemaster did, the more consistant.......jackie
Ignition problems in the action can also show flyers at those distances. Most folks dont check for things like this but they are very real. If you dont get anything figured out with Boyds suggestion " And i might add it is a very good suggestion" Then maybe you can have someone look for drag in your firing pin or cocking assembly. Just a thought. Good luck friend! Lee
Boyd Allen
Active member
A little story along the line of Lee's post...
Some time back, when I was discussing, with Greg Tannel of Gre-Tan Rifles, what had lead him to bush bolts' firing pin holes, and modify the pins, so that the pin tips stay within their holes for the full travel of the pin, he told me of a rifle (based on a Remington, I believe) that was driving him crazy with an occasional random flier (I believe that it was part of a long range bench rifle.). Finally, he tried bushing the pin, and just to make sure, he made the bushing long enough, and machined the pin tip far enough back, so that the pin would not have to "find" the hole as it moved forward. THAT solved the problem. I'll forward my mailing address so that you can know where to send the check.
Some time back, when I was discussing, with Greg Tannel of Gre-Tan Rifles, what had lead him to bush bolts' firing pin holes, and modify the pins, so that the pin tips stay within their holes for the full travel of the pin, he told me of a rifle (based on a Remington, I believe) that was driving him crazy with an occasional random flier (I believe that it was part of a long range bench rifle.). Finally, he tried bushing the pin, and just to make sure, he made the bushing long enough, and machined the pin tip far enough back, so that the pin would not have to "find" the hole as it moved forward. THAT solved the problem. I'll forward my mailing address so that you can know where to send the check.
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Andy Cross
New member
You might be right Skeetlee
My farther had a .243 once. Rem 700, laminated stock, BR trigger, Madco barrel, and could shoot half moa at 200yds if you read the flags well. All of a sudden it began producing flyers. Checked everything including chronographing the loads. Then he had a guy check the lock time with a contraption he devised. Bugger me every 7 to 8 shots something would slow it down. Don't remember how much. Cleaned up that problem and it went back to its good old self.
Andy.
My farther had a .243 once. Rem 700, laminated stock, BR trigger, Madco barrel, and could shoot half moa at 200yds if you read the flags well. All of a sudden it began producing flyers. Checked everything including chronographing the loads. Then he had a guy check the lock time with a contraption he devised. Bugger me every 7 to 8 shots something would slow it down. Don't remember how much. Cleaned up that problem and it went back to its good old self.
Andy.
If you want better accuracy?? the following will help:
1. Clean up the contact areas as noted in the first several posts,
2. Build a rack/shelf/something to get the scale at eye level
so the user can see the index marking and the end of the beam-looking
straight on, may want to set up a magnifier
3. make sure the pan hangs the same each time, as noted in am early post.,
4. make sure the beam is 'zeroed' the same with every use,
5. dont try to weigh small amounts-less than 10-15 gr. if need be
do it by differential weighing.-see below-
Differential weighing involves putting a good sized quantity on the scale and then removing the amt needed. If you need 1.5 gr weigh out exactly 20 gr. Then remove your 1.5 gr-ie that amount that is removed to make the quantity remaining to weigh 18.5 gr. Could be called 'negative weighing'. Esp good for very small quantities-couple grains or less..
1. Clean up the contact areas as noted in the first several posts,
2. Build a rack/shelf/something to get the scale at eye level
so the user can see the index marking and the end of the beam-looking
straight on, may want to set up a magnifier
3. make sure the pan hangs the same each time, as noted in am early post.,
4. make sure the beam is 'zeroed' the same with every use,
5. dont try to weigh small amounts-less than 10-15 gr. if need be
do it by differential weighing.-see below-
Differential weighing involves putting a good sized quantity on the scale and then removing the amt needed. If you need 1.5 gr weigh out exactly 20 gr. Then remove your 1.5 gr-ie that amount that is removed to make the quantity remaining to weigh 18.5 gr. Could be called 'negative weighing'. Esp good for very small quantities-couple grains or less..
T
twentytwoguy
Guest
To my thinking waiting 20 seconds for the Cm to spit out a charge and then taking the added step of reweighing and trickling it on a beam or digital scale is double effort and a slower process since it only takes about 20-25 seconds to throw and trickle a load to sub 2-kernel accuracy on a beam or digital in the first place with little effort. Plus my buddy's CM commonly overthrows Varget stick powder and a buzzer sounds and he has to often dump the charge back in the hopper and start over.
But fellow shooters needing less demanding accuracy for short-range comps and hunting loads think they are the best thing since sliced bread and save them time since they can seat bullets while the machine is spitting out powder.
Repeated 300 yard ladder tests showed that 3/10 th's made a considerable difference in vertical as the groups walked up and nearly over the target and am guessing that at even longer ranges 2 or 3 tenths could make a big difference and with stick powder like Varget that's not too many kernels. Also anecdotally if you put just 3 or 4 kernels of Varget nested together and put a match to them there is noticable energy expended.
When the wind is howling disregard all the above you may never notice a few kernels anyways Lol.
But fellow shooters needing less demanding accuracy for short-range comps and hunting loads think they are the best thing since sliced bread and save them time since they can seat bullets while the machine is spitting out powder.
Repeated 300 yard ladder tests showed that 3/10 th's made a considerable difference in vertical as the groups walked up and nearly over the target and am guessing that at even longer ranges 2 or 3 tenths could make a big difference and with stick powder like Varget that's not too many kernels. Also anecdotally if you put just 3 or 4 kernels of Varget nested together and put a match to them there is noticable energy expended.
When the wind is howling disregard all the above you may never notice a few kernels anyways Lol.
Guys, mike in co is the smartest man in any forum in the entire universe. In another thread "he" determined and told us all that our chargemasters are basically bathroom scales disguised as loading scales. And he talked down to us while telling us our tools are just junk. I try to just stay out of this stuff but it's just hard....
Dave T
Dave T