Hopefully this is not a stupid question but I don't know the answer. I have a 505 RCBS beam scale and my question is when weighing loads and trickling up the charge do you "bump" the beam to get it to break the magnetic hold and then let it settle or just trickle it up until at zero?
I don't know what is correct or not but I do know that my scale will weigh a charge different if I trickle up to it or over charge and take away.
I have come to make it a practice to make sure that I let the scale settle from the top down. I push down on the powder holder and let it settle to zero. It takes a little longer for each charge but my SD has gotten better once I realized my scale had quirks.
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First plug it in, and let it warm up for at least 1/2 hour..
(just kidding) I bump the pan when trickling, and try to time the swings until I know I'm really close. My personal theory is that it takes a little bump to break the magnetic hold on the beam. I've trickled powder so slowly that my Hornady scale didn't register the change at first, then shot over my target weight. Really, as long as you end up at the weight you want, it doesn't matter how you do it.
"...do you "bump" the beam to get it to break the magnetic hold..."
No. The greatest advantage of magnetic damping is that it only works on a moving beam, there is NO residual magnetic hold because the magnet only acts on the copper bar when the beam is moving. When the beam is stopped there is no more interaction at all when the beam slows to a stop.
Most beam hang-ups come from dirty pivots or bearings. Clean the beam's axle (the cross bar part) and the bearings with alcohol wetted Q-tips and toothpicks until they are spotlessly clean.
The second most common hang-up point is when one end of the pivot bar rubs against the bearing cage. Simply center the beam so the bar is free from any end contact and your beam will swing free, no bumping required.
I have vastly improved the accuracy of my scale by strumming (sp) the fingers of my freee hand on the desk near the scale to break the magnetic dampning effect which does cause inaccurate reads. I do this as the electronic trickler dribbles in the last few grains.
As a previous poster stated, without vibration of some kind you can add a few kerrnals without getting the beam to move at all.
I keep my scale clean and covered at all times. If there is any dirt causing the beam to hang up, I can't detect it. I have always believed that magnetism was the culprit.
Thanks for the replies guys. I think I will try the things you mentioned and after weighing, I will take off the pan and powder and measure it again to see if I get the same weight.
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