Lyman Pro-500 scale - whacky

All of a sudden my Lyman Pro-500 balance has gone whacky! I make a regular habbit of checking the zero before I begin reloading. And for 6 years I never had a problem with my Lyman powder scale.

Just last evening I couldn't get it to zero. It's like the gold pan is 1/2 grain light now. I inspected the bar and could find no debris sticking to it. And the 1/2 grain light is with the leveling wheel turned to its lowest point, or however you describe it. Basically I took into account that the wheel can be turned to bring it onto zero - not possible.

The agate notches are clean. The bearings on the bar look good and sharp.

I'm perplexed.

is the table level???
i have 3 scales & have had to reO all of them by adding a shot to the pan holder so to have the adjusting wheel centered on its travel.
it`ll take a bit of juggling different combos but it`ll work.
& yes i own check weights & there as close as any single beam will be!!

GP100man:cbpour:

By any chance is there a fan or heating duct blowing air on it?

No fan. Hot water baseboar heat, so no forced air.

Table is not perfectly level I'm sure but the table hasn't changed for over a year. The balance has worked fine for several months in the same location.

The arm of the balance is obviously not level. If it was visibly horizontal, I would know that the body of the balance just needed to be leveled properly. However when the weights are all at zero you can see the arm is pointing downward.

I checked with a set of check weights and it seems to carry the 1/2 grain descrepency from .5, 2.0, 5.0, 10.0, through 100.0 grains. Perhaps I need to just add a shot to the tray holder. But still, it leaves me feeling a bit uneasy thinking that it could be something else.

Could static electricity have any affect? Not that I know that it is charged, but the only thing I did to it recently was dust it off and laid a flannel rag over it as a sort of cheap dust cover. If this is possible how does one go about de-charging it?

Jaque...

Had the same thing happen with my RCBS 10-10. Had bought an electronic scale and hadn't used the RCBS for a year or so. The electronic died and when I took the 10-10 out of storage it wouldn't zero without screwing the leveling leg all the way up. Was no problem to recalibrate by adjusting weight of pan holder but never did figure out why it went out in the first place.

Bill

Rural setting/housing? Cold climate?
Frost shifts foundations every winter. It doesn't have to be enough to crack the plaser. But it can trhow floors out of leverl
Pepe Ray ( 15*F here. yep Jack Frost)

Most such problems are from the beam axel ends rubbing against the agate bearing clips. Center the beam between the bearings and it should be good.

Gauss differential. Magnets get old. My dampener went out on me once a long time ago on aLyman I had never worked right again. Ceramic magnets, of course. Won't hold for beans after a few years. Alnico ones last and last.

Housedad,

I'm sorry but much of your post went over my head. Were you saying that ceramic magnets are inferior quality and won't last? Alnico magnets last much longer? If Lyman uses the inferior magnets, who uses Alnico magnets?

It seems as though the dampening is working - in other words it doesn't really take long to stop oscillating. In fact there are times when it stops so quickly I check the bearings to see if they're obstructed.

There is another thing to check. It happened on a balance beam scale of mine, but yours may be different. There is a pin with a knife edge that holds up a clevis that in turn holds the wire support for the powder pan. On my scale, that pin is held in place by the threaded rod that the zeroing weights run in and out on. In zeroing my scale once, I loosened the threaded rod, and that knife edge pin rotated so that the knife edge was not pointed up anymore. The scale got squirrelly as hell until I noticed what had happened.

Mine still worked, it just did now want to zero no matter how much I adjusted the foot. The magnets tried to pull it away Yes, ceramic magnets weaken over time and their pole center will shift.

There are so many things that can go wrong with these balance scales. you need to sit down with a magnifier and carefully, and I mean carefully inspect for everything, including cleaning it well.

My problem was pretty rare. Most of the time it is dirt, something not placed right, or something tiny broken

Housdad,

Is there a company who makes reloading balances using Alnico magnets? I'm wondering if I can't get this resolved if I should go with RCBS, Redding, or ??

i bought a denver mxx-123 which is about 300 bucks, its in a room with no heating vents, no drafts, it sits on a 18x12x3 granite block. it has been on for 2 days and still maintains its zero,its accuracy is +/-.02 gr........with about a 2 second response time............

just eliminated another potential problem...


mike in co

I also have a rcbs 10-10. I'll try to get over to my shop to take a look. I seem to remember it was alnico, but even that may have changed over the years. The 10-10 I have is still good after over 15 years.

Bion

The older beam scales seem to be better made the newer one nowadays...

As this seem quite a consistent error, my guess would be, that the damper blade has taken a knock at some point, it might even be loose where it's riveted to the beam. It only takes a few thou of movement of the copper blade to alter the zero setting a couple of grains.

I really don't think the magnets are a problem - the strength of the magnets will effect the damping ability but the scale would still work exactly the same even it you took the magnets right out, it just wouldn't have any damping.

I have an older Lyman 500 that is basically useless. I can't find anything out of order with it, but it never returns to the same place with a check weight. Sometimes it will show heavy, sometimes light without changing a thing. I would send it back to Lyman but have had very poor customer service with them several times in the past and don't want the hassle.

maybe your table hasn't moved, but your house might have shifted? I would check for level on the tabel again, but I don't know if it would be noticeable

sorry pepe I somehow didn't see your post, I guess my eyes shifted, LOL