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scale tune up
- Thread starter bdale
- Start date
B
B.Johnson
Guest
A set of precision weight,s would be a good start. Then you can watch any precision just go away while you work.
Boyd Allen
Active member
Step one: level the main frame with a good combination square or torpedo level, and adjust the weights in the pan holder so that the scale is perfectly zeroed. This will take some little bits. I used a plastic collar stay. I pulled out a piece of shot, reassembled the holder, set the pan on it, and put plastic pieces in the pan till it was perfectly balanced. Then I transferred the pieces into the cavity in the pan holder with the rest of the shot.
Step two: Use an inexpensive diamond hone (Mine is a worn coarse.) to sharpen (maintaining the angles by eye) the knife edges, till they show no shiny spots when looking at the edges straight on, then deburr with the side of a hard pencil lead. About the same time, remove the agate bearings and clean them and the spaces that they sit in with alcohol and Q tips. Reassemble. Play with the wire hanger that rests on the other set of knife edges so that it is spread wide enough so that while not rubbing on its sides at the outside ends of the knife edges, it is prevented from shifting from side to side. When using the scale, make sure that main knife edges ( on the agates) do not make contact on their ends. Also, pick up the whole pan and holder assembly off of the pan knife edges by holding the loop that the pan holder passes through, between your thumb and finger, and then set it back down on its knife edges so that they are at the very top center of the loops that rest on them. Weigh the brass weight that is in the leveling screw, you may need to tune the sliding weight, that is used to make 10 gr. adjustments. Weigh other things, like test weights, or ordinary objects like various coins that have been weighed using a more accurate scale, preferably one that is good to .002 grain. Do this a little at a time, so that you have time to think over what you are doing. To stop the pan from swinging, you can place your right finger tip on the table, so that the swinging pan just touches the side of your finger. Good luck Let me know how it went.
Step two: Use an inexpensive diamond hone (Mine is a worn coarse.) to sharpen (maintaining the angles by eye) the knife edges, till they show no shiny spots when looking at the edges straight on, then deburr with the side of a hard pencil lead. About the same time, remove the agate bearings and clean them and the spaces that they sit in with alcohol and Q tips. Reassemble. Play with the wire hanger that rests on the other set of knife edges so that it is spread wide enough so that while not rubbing on its sides at the outside ends of the knife edges, it is prevented from shifting from side to side. When using the scale, make sure that main knife edges ( on the agates) do not make contact on their ends. Also, pick up the whole pan and holder assembly off of the pan knife edges by holding the loop that the pan holder passes through, between your thumb and finger, and then set it back down on its knife edges so that they are at the very top center of the loops that rest on them. Weigh the brass weight that is in the leveling screw, you may need to tune the sliding weight, that is used to make 10 gr. adjustments. Weigh other things, like test weights, or ordinary objects like various coins that have been weighed using a more accurate scale, preferably one that is good to .002 grain. Do this a little at a time, so that you have time to think over what you are doing. To stop the pan from swinging, you can place your right finger tip on the table, so that the swinging pan just touches the side of your finger. Good luck Let me know how it went.
T
twentytwoguy
Guest
Boyd has a great tutorial but if your sheepish like me about your precision scale Lol just send it to Scott with a little jack and have him do it. If yours is new he may well reccomend getting an older model made back when Ohaus was making them for RCBS and supposedly they were far superior for reasons unknown to me. You can get $100. for yours on the For Sale boards if that's what he wants you to do and his are about the same price so the money will wash out.
I can't speak highly enough about mine that I got from him and the accuracy/repeatability is amazing and I never use my expensive digital scales any more. I am just way to skittish about taking a diamond file to my beam scale Lol but it probably sounds worse than it is and Boyd's advice is no doubt spot on and admittedly it's out of my comfort zone.
I can't speak highly enough about mine that I got from him and the accuracy/repeatability is amazing and I never use my expensive digital scales any more. I am just way to skittish about taking a diamond file to my beam scale Lol but it probably sounds worse than it is and Boyd's advice is no doubt spot on and admittedly it's out of my comfort zone.