Lyman M5 Scale Tuning

[rijndael]

I have an older Lyman M5 scale. It's as sensitive as my Parker tuned 1010, but this Lyman reads .2 gr too high. I've cleaned the knife edges and pivots on the scale. There are no obvious burrs. I've tried adding pencil lead to the friction surfaces. How can I fix the + 0.2 gr issue?

 

[chkunz]

You have leveled the scale with zero weight so it reads zero at the point, right?

 

[rijndael]

Yes.

 

[hoz53]

I have an older Lyman M5 scale. It's as sensitive as my Parker tuned 1010, but this Lyman reads .2 gr too high. I've cleaned the knife edges and pivots on the scale. There are no obvious burrs. I've tried adding pencil lead to the friction surfaces. How can I fix the + 0.2 gr issue?

youve checked it with check weights? after doing what chkunz says if it still doesnt read right you can add weight to the large poise ( part with the pointer you move back and forth along beam to set the weight) try using tape for this.

 

[rijndael]

try using tape for this.

Great idea. Thank You.

 

[hoz53]

Great idea. Thank You.

hope it works for you

 

[chkunz]

Have you done a calibration curve, calibration weight vs indicated weight? Do this on graph paper and see what it looks like. As you state, this curve would go thru zero, zero weight and zero reading so there is no 0.2 grain offset there. But how does it look as you add the check weights? Probably not a consistent 0.2 grain bias. The shape of this calibration curve will be helpful.

 

[rijndael]

I'll gather that data next.

 

[Fotheringill]

I know this is widening the entrance to the rabbit hole, but if you have a set of cheap check weights, be aware there may be one or two (or more) in the set that may be off. I have a cheap set and they read off by about that amount when checked against the reading on a GemPro equivalent, a check weight that came with an electronic scale and a Lee and a Redding beam scale.

 

[hoz53]

--

I have an older Lyman M5 scale. It's as sensitive as my Parker tuned 1010, but this Lyman reads .2 gr too high. I've cleaned the knife edges and pivots on the scale. There are no obvious burrs. I've tried adding pencil lead to the friction surfaces. How can I fix the + 0.2 gr issue?

you might find this thread of interest

http://benchrest.com/showthread.php?75444-Accurize-a-balance-beam-scale

 

[swadiver]

i have the Lyman check weights. my shooting buddy has the same. on my 3 scales (two digital, one a Scott Parker tuned Lyman M5 beam scale), all read the check weight .1 gr high. my buddies weights all read within .01 gns on his two digital scales

it really does not matter as long as you get repeatable results at your measured best load

 

[danny]

I have an older Lyman M5 scale. It's as sensitive as my Parker tuned 1010, but this Lyman reads .2 gr too high. I've cleaned the knife edges and pivots on the scale. There are no obvious burrs. I've tried adding pencil lead to the friction surfaces. How can I fix the + 0.2 gr issue?

You are not supposed to add pencil lead to or lubricate the scale.

Danny

 

[rijndael]

You are not supposed to add pencil lead

Burnishing the knife edge with mechanical pencil lead is not an uncommon tweak.

http://benchrest.com/showthread.php?75444-Accurize-a-balance-beam-scale&p=634433#post634433

 

[danny]

Burnishing the knife edge with mechanical pencil lead is not an uncommon tweak.

http://benchrest.com/showthread.php?75444-Accurize-a-balance-beam-scale&p=634433#post634433

Burnishing and "adding graphite" to it are two different things. Graphite should not be "added" to the scale/knife edges. Two different things are being mixed together here. Anything that goes on the knife edge after burnishing should be removed and the knife edges cleaned to bare metal.

If anyone wants to lubricate or put graphite on their scale, I am all for it, as it is their scale to do with as they please. I just hope that I get to read about it.

Danny

 

[rijndael]

Burnishing and "adding graphite" to it are two different things. Graphite should not be "added" to the scale/knife edges.

You're trying to create a difference where one doesn't exist.

 

[danny]

You're trying to create a difference where one doesn't exist.

That isn't true. Burnishing is working a metal surface to smoothen it and the original poster is talking about putting graphite on the knife edges. I presume that he feels that he wants to lubricate it, and is in fact doing or did so.

Danny

 

[swadiver]

That isn't true. Burnishing is working a metal surface to smoothen it and the original poster is talking about putting graphite on the knife edges. I presume that he feels that he wants to lubricate it, and is in fact doing or did so.

Danny

all i can say is that i brush the knife edges very gently with soft mechanical pencil lead and am getting amazing results in sensitivity and repeat-ability. it is an improvement over just the work Scott Parker did on it.

i use a web cam aimed at the pointer, glued a needle to the pointer end to indicate on the scale marks, and can easily see one grain of IMR 8208 XBR powder added to the pan ( the smallest grain powder i use) indicate on the scale. my Grizzly Bald Eagle digital scale will not register a change with one such grain added.

i don't know if the pencil lead trick is supposed to work or not, but after testing the scale with and without it, i will continue to use that tweak on the scale

 

[rijndael]

the original poster is talking about putting graphite on the knife edges.

I didn't dump loose graphite on there. I applied some, with pressure, from a pencil tip. I wiped away the excess with a quick swipe of a q-tip. In the end, graphite was "added to" the surface.