barnfrog
Member
Does anyone know if the graduations above and below the zero mark on a Lyman M5 beam scale are intended to indicate tenths of a grain, or are they just an uncalibrated reference? Neither the manual nor anything I've found online makes any mention of them. This is kind of long-winded, trying to anticipate the questions folks might ask, so if you don't want to read all the stuff I've done you can skip to the last paragraph.
I have a used M5 and have been cleaning and testing it to see if it is working correctly. Cleaned the knives and bearings with acetone and did some basic repeatability checks, and checked weights of different objects between the M5 and my cheap digital scale. Don't have a set of check weights yet, but will be getting a set in the near future. No shiny spots I can see on the knife edges.
After verifying the scale was zeroed, I moved the large poise to the 5 grain mark, and metered out 5 grains of powder (pointer at zero mark). Then I moved the large poise to zero and moved the small poise to its 5 grain mark. The pointer came to rest at the zero mark, so I then moved the small poise back to zero and the large poise to the 5 grain mark and again the pointer came to the zero mark so the small and large poise appear to be calibrated with each other.
Then I emptied the pan and put it back on the hanger, moved the large poise back to zero and the pointer came back to the zero mark, so it appears to be holding its zero.
So then I moved the small poise to the 0.5 grain position, but the pointer only moved 4 graduations. So either those marks aren't meant to indicate tenths of a grain, or the small poise isn't causing 0.5 grains worth of movement. I'm inclined to think the former, but wondered if anyone knew for sure. Not sure why I bothered to check that. I've noticed the newer scales don't have those graduations, just the larger marks above and below the zero mark.
Thanks for any help satisfying my curiosity.
I have a used M5 and have been cleaning and testing it to see if it is working correctly. Cleaned the knives and bearings with acetone and did some basic repeatability checks, and checked weights of different objects between the M5 and my cheap digital scale. Don't have a set of check weights yet, but will be getting a set in the near future. No shiny spots I can see on the knife edges.
After verifying the scale was zeroed, I moved the large poise to the 5 grain mark, and metered out 5 grains of powder (pointer at zero mark). Then I moved the large poise to zero and moved the small poise to its 5 grain mark. The pointer came to rest at the zero mark, so I then moved the small poise back to zero and the large poise to the 5 grain mark and again the pointer came to the zero mark so the small and large poise appear to be calibrated with each other.
Then I emptied the pan and put it back on the hanger, moved the large poise back to zero and the pointer came back to the zero mark, so it appears to be holding its zero.
So then I moved the small poise to the 0.5 grain position, but the pointer only moved 4 graduations. So either those marks aren't meant to indicate tenths of a grain, or the small poise isn't causing 0.5 grains worth of movement. I'm inclined to think the former, but wondered if anyone knew for sure. Not sure why I bothered to check that. I've noticed the newer scales don't have those graduations, just the larger marks above and below the zero mark.
Thanks for any help satisfying my curiosity.