Reloading scale trouble -problem solved

[Parker2020]

I have an old balance beam scale that came with my Dillon reloader I purchased many years ago .
It has always worked flawlessly until recently it started sticking when trying to calibrate "Zero" . If you nudged the beam upward after settling on "0" the beam would stick in the upward position and same result if beam nudged in the downward direction and would not return and settle on Zero like it should .
After checking everything out looking for a bind I found nothing wrong . Scale was Dillon blue but made by Ohaus .
After going on the Ohaus website I discovered the scale had magnetic damping which was news to me . With the balance beam removed I slid a screwdriver tip up and down in a slot that a copper plate attached to the pointer end of the balance beam normally swings to see if the magnet was working .

I could feel magnetic pull on the screwdriver . "OK so the magnet is still working I thought ." Upon reassembling the scale it was now suddenly working perfectly once again . I think I stored the scale disassembled for quite awhile and maybe this messed up the damping magnet polarity somehow ?
Maybe this is common knowledge to some but I just thought I would pass it along in case someone has a similar type scale sticking and or not acting right .

[sofbak]

Not sure how the beam balances on the Ohaus/Dillon scale, but had the same issue with a Lee unit.

The balance rides on a knife edge in the body of the scale. There is a block with a groove on the bottom of the balance beam, and the knife edge sits in that groove. If the block groove doesn't sit on the knife edge the beam gets misaligned and the mag dampers make it "sticky".

[sigstroker]

I've never heard of a magnet stop working. It's one of the fundamental forces of the universe, like gravity. More likely is there was some schmutz or something wedged in that area and you knocked it loose with the screwdriver.

[Parker2020]

[QUOTE=sofbak;25583611]Not sure how the beam balances on the Ohaus/Dillon scale, but had the same issue with a Lee unit.

The Ohaus scale works on the same principle (a knife edge supported /balanced across 2- v blocks ) The beam damping works by way of a copper plate interacting with magnetic flux produced by magnet(s)

[sofbak]

^^^OK. Help me here. Copper is non-ferrous. So how do opposing magnetic fields have any effect?

Until you can explain that, I'll stick to my explanation-your balance beam was not properly aligned to the base and the mag dampers.

[Parker2020]

I've never heard of a magnet stop working. It's one of the fundamental forces of the universe, like gravity. More likely is there was some schmutz or something wedged in that area and you knocked it loose with the screwdriver.

Having spent much of my working life bench testing induction disk protective relays to a tolerance of +/- 1/2 of 1% I know what to look for regarding debris stuck to a magnet .
These relays use a rotating aluminum disk suspended between damping magnets and I have witnessed many times a barely visible metal shaving stuck to the damping magnet drag on the disk affecting accuracy of the relay . Trust me when I say that's not what the problem was with this scale .

[xfer42]

^^^OK. Help me here. Copper is non-ferrous. So how do opposing magnetic fields have any effect?

Until you can explain that, I'll stick to my explanation-your balance beam was not properly aligned to the base and the mag dampers.

Ever drop a magnet down a copper pipe?
It slowly falls without touching the sides.
The moving magnet induces current into the copper, which creates an opposing magnetic field.

[sofbak]

^^^ "The moving magnet induces current into the copper, which creates an opposing magnetic field."

Right, but you have two opposing mag fields in the scale config. And not nearly the same velocity as a scale.

Explain this diff please.

[Revoman]

Since you stored it for a long time separating the parts, it likely built dust in the knife groove/pocket, which would dampen its movement, causing you to touch it to get it moving. It doesn't take much. Keep it clean it'll work great.

[Parker2020]

^^^OK. Help me here. Copper is non-ferrous. So how do opposing magnetic fields have any effect?

Until you can explain that, I'll stick to my explanation-your balance beam was not properly aligned to the base and the mag dampers.

A couple of posts from other shooting /reloading forums ...

1) It is pretty common that shooters have no clue about how magnetic damping works. When a conductor (the copper blade on your scales beam that you are considering removing) is moved through a magnetic field, within the conductor, eddy currents are generated, as well as a magnetic force opposing the field through which it is moving. The key word here is moving. When the beam is not moving, no eddy currents are being generated, no magnetism is generated. The magnets exert no force on the scale beam.


2) I have noticed that some scales have developed a permanent magnetic field in their beams. I have tested this several times by exchanging beams with the scale body. The problem follows the beam. Remove the magnets, and the problem goes away. The problem most typically manifests itself in not allowing the beam to achieve zero. Add a kernel, the beam goes 2/10ths high, take it out, it goes low. Lower the leveling foot and the beam still points low, etc. I have tried a demagnetizer with no luck. This is one issue for which i have not yet developed a cure. I'd love to get some advise from someone far more knowledgeable than me.

[TimRB]

I have noticed that some scales have developed a permanent magnetic field in their beams.

I find this hard to believe, depending on your scale. The beam of my RCBS 505 is solid aluminum, and the damping paddle that goes into the magnetic field is solid copper. The two parts are pressed together, so there is no ferrous metal nearby. Holding a magnetic compass close by causes no deflection of the needle. Holding the compass near the magnet causes a strong deflection (duh).

I suggest a similar compass check with your scale. If it really has become magnetized, then there must be ferrous metal present.

Tim

[sofbak]

This is what I was referring to:

"The key word here is moving. When the beam is not moving, no eddy currents are being generated, no magnetism is generated. The magnets exert no force on the scale beam."

I would have thought a degaussing would solve your issue if you had ferrous metal in the beam. Guess not (?).

[TimRB]

I would have thought a degaussing would solve your issue if you had ferrous metal in the beam.

Certainly if the beam did, in fact, become magnetized somehow, it would be hard, if not impossible, to zero the scale. I just don't happen to think that's the problem.

Edit: I doubt that anyone here has equipment that could degauss a piece as large as a scale beam.

Tim

[Parker2020]

The post I found from an individual with the same scale (See #2 in reply above ) and same symptom as my experience sure seems to confirm the unusual behavior out of my scale . Having my scale apart repeatedly looking for the source of the erratic sticky behavior only to find nothing out of the ordinary is baffling .

1) Inspected all components of scale for clearance issues physical binding
throughout beam travel range OK check

2) removed beam and inspected knife edged pivots for wear /damage &
V-blocks & all OK check reassembled same problem

3) removed beam and looked for metal shavings or debris stuck inside damper gap located in base and inspected copper plate using magnifying glass nothing found check reassembled same problem .

4) again removed beam and placed screw driver tip in damper gap to see If I could detect magnetic attraction - I did check reassembled beam and now working perfectly

I was systematic and thorough in my testing but never found any of the typical problems associated with a sticky scale movement . Pretty simple device really and not too much can go wrong . I tried using a compass around the removed balance beam first thing this morning and observed no needle deflection . If this ever happens again that will be the first thing I check though.

[sofbak]

Well, given all the presented info, it seems that this:

"4) again removed beam and placed screw driver tip in damper gap to see If I could detect magnetic attraction - I did check reassembled beam and now working perfectly"

is the path to resolving the anomaly. But I can't conjure why.
Are both magnets securely mounted?
Hate it when this happens.