I have been working with a set of check weights on the 502 scales I bought. They started showing a shift in the readings, I found that the copper tab between the magnets would move. It extends through the beam so I used a small ball peen hammer to tighten it, didn't take much. It's a little tricky to set the beam in the scale so I figure someone tried to force it.

That made them more consistent but still showed a progressive weight gain to about 210 grs., didn't go any heavier. Next I started working with the lead shot ballast. I took out one and started replacing with smaller shot. Between changing and resetting and weighing it took a while. Ended up being almost dead on from 0-150 grs. It gains about 2 tenths from 150 to 210 and is back dead on with a 20 gram and 30 gram weight from my Pact electronic scale. Being that these are so close to my check weight from 0 to 150 grs I think I keep them.

Although it took a while I learned a lot and I enjoyed tinkering with them. It gives you a greater appreciation for the guys that can really tune these things. I do think a set of check weights is money well spent.

I also worked some with the Ohaus Dial-O-Grain 3100 scales, basically all I did was clean them up. All I can say is WOW, practically dead on through the over 800 grs I had. On this model the dial goes to 110 grains. Just dial and weigh. It's no wonder these rarely show up, I like them. Does anyone have any idea when Ohaus stopped production of these?

Have fun
Dave