I set the poises on my lyman m5 to zero and adjusted the pointer to zero. When I set the poises to 35gr and put in the 35 test weight it shows one tenth high. The 35 test weight is verified. Two other scales read right on 35gr. So i put the 35 in the m5, it shows one tenth high so I adjust the pointer screw to get a zero. Now all 3 scales read the same with 35gr test weight and it is repeatable. Am i doing this correctly? The 260.9 test weight reads dead on with the scale zeroed at both poises set on zero and pointer at zero and pointer set at zero. Must be a linear thing going on. Whatcha think.
Beam scale zero
- Thread starter cwebster
- Start date
I think that is what i would do. Tommy Mc
You might ask @sparker.. Re-zeroing at the test weight does not seem like the ideal solution to me. But then, I'm at 'zero' when it comes to experience with scale tuning.
I'm willing to try and explain my intuition though.. if incorrect, it wouldn't be the first time this year I was.. ahhh, suboptimal in my reasoning. That said:
With the poises (?) at zero, adjusting height pins the left side of a X-Y plot of weight .vs. error. After doing this (as you have), if you find that the error increases as you add more weight - what is happening may be due to a non-linear response from the scale. I.e., the more weight you add the greater the error (distance) between a plotted line of actual weight .vs. indicated weight. The gap is error, but by starting all lined up at zero any error then will increase (or decrease) in magnitude as measured weight goes higher. In a plot, the two lines get farther apart as you move to the right.
How does that happen? There are weights in the bottom of the tray holder.. and if you removed one 'bb' from that spot and re-zeroed, you might find that the scale indicator now lines up. Again - I'm trying to sort this out in my head with no real-world experience to back it up so.. grain of salt, right? (Looking for someone with experience to chime in!)
Principle at work here is that with three of four variables fixed:
1) Test weight remains 35gr
2) Pivot point (blades) remain at the same spot
3) Poises set the same
What would cause the pointer to go down 0.1gr? At least one answer is less weight at the tray.. though we did adjust the pointer at zero again.
This should change the 'slope' of the line - a plot of measured weight .vs. error. What my weary brain can't tell you from experience is if you want to a) add weight and re-zero or b) subtract weight and re-zero.
Hopefully in the above ramble lies a principle of operation that'll get us to the right answer.
?
I'm willing to try and explain my intuition though.. if incorrect, it wouldn't be the first time this year I was.. ahhh, suboptimal in my reasoning. That said:
With the poises (?) at zero, adjusting height pins the left side of a X-Y plot of weight .vs. error. After doing this (as you have), if you find that the error increases as you add more weight - what is happening may be due to a non-linear response from the scale. I.e., the more weight you add the greater the error (distance) between a plotted line of actual weight .vs. indicated weight. The gap is error, but by starting all lined up at zero any error then will increase (or decrease) in magnitude as measured weight goes higher. In a plot, the two lines get farther apart as you move to the right.
How does that happen? There are weights in the bottom of the tray holder.. and if you removed one 'bb' from that spot and re-zeroed, you might find that the scale indicator now lines up. Again - I'm trying to sort this out in my head with no real-world experience to back it up so.. grain of salt, right? (Looking for someone with experience to chime in!)
Principle at work here is that with three of four variables fixed:
1) Test weight remains 35gr
2) Pivot point (blades) remain at the same spot
3) Poises set the same
What would cause the pointer to go down 0.1gr? At least one answer is less weight at the tray.. though we did adjust the pointer at zero again.
This should change the 'slope' of the line - a plot of measured weight .vs. error. What my weary brain can't tell you from experience is if you want to a) add weight and re-zero or b) subtract weight and re-zero.
Hopefully in the above ramble lies a principle of operation that'll get us to the right answer.
?
yes
On the redding 2 i have , set poises at zero, put 35 test in place and it will zero.The 260.9 from the m5 is spot on the redding. The m5 is a tenth off at lower weight tests
Re: "The 260.9 test weight reads dead on with the scale zeroed at both poises set on zero and pointer at zero and pointer set at zero. Must be a linear thing going on. Whatcha think."
Missed the point that your M5 was correct at both ends.. Glad Scott weighed in!
weighing 10gr the m5 and the redding match up ??????
My M5 sits in its box on the shelf because of the same issue and it doesn't repeat. The 505 I bought in the 80's and the D5 bought last year both zero and repeat fine. I always zero my scale as near the charge weight as possible, probably not necessary though.
centerlineseal
Gold $$ Contributor
That's what I do as well and if I had 1/10 grain test weights, I'd go with exact charge.
My test weights go down to 1/10th (.09 actually) of a grain, but most of the time I'm too lazy to get that close. LOL
If you do a search on it you will find a post on beam scales I posted awhile back.... It was some good info I believe on some things you can do to help them.... Try and get your bench level , it helps.... My bench is slick on top and the scale will move way to easy.... I have been thinking on how to fix that for awhile.... I still use it but went digital years ago...
^^^^ that
I use line levels in all directions on the platform I built for my scale to sit on. I can shim the platform if needed to compensate for wherever on the bench on want to place scale platform. That helps my scale stay dead on.
I use line levels in all directions on the platform I built for my scale to sit on. I can shim the platform if needed to compensate for wherever on the bench on want to place scale platform. That helps my scale stay dead on.
just use check weights closet to your charge weight with your leveled m5 and adjust the pan weights to where it is dead on at closest check weight. Glue a pin on your beam pointer and use a bore scope with laptop or your hone propped up to see magnified level view. Video is with 30gr in pan
I use my wheeler scope level and set it on the flat spot right infront of where the ...ah heck i'll take a pic and post it. easier than explaining! I tried a 6in small level in the pastView attachment 1402995 but it only fit on the top lip and that didnt seem to be that parallel to the base.
BoydAllen
Gold $$ Contributor
I have done some work on my own scales, and they all work pretty well. After I clean the agates that the main knife edges sit in, and their seats, the next thing that I do is to level the scale body and adjust the weights in the pan holder so that the beam pointer is pointing exactly to zero with the pan on and the poises set to zero. I want the CL of the edges to bisect the angle of the agates. From there I sharpen the edges, and do a couple of other things. With a scale like the M5 or my 10-10 there are flat surfaces that making the leveling easy. Other designs are more challenging, with only the tops of the agate retainers to work with. This can be a bit tricky, but I can make it work.
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