AMATEK Model T Dead Weight Tester

[crazyjim30]

My school has asked me to recondition some donated calibration equipment. The DWTs are supposed to be EXTREMELY precise pieces of equipment and the condition they're in is nothing short of a crime. I've brought one unit back to life and I'm waiting on parts for the second one.
The next step is attempting to restore the weights. I'm not even sure what they're made of. "Green and crusty" would be a fair visual description. Since they're​ very precise weights, I'm reluctant to take a wire wheel to them for fear of removing material and throwing the weight off.
Does anyone have any suggestions for removing what I *think* is corrosion or oxidation? I'll post some pictures tomorrow afternoon when I swing by the lab.

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[gte718p]

If the weights are in that bad of shape they are probably out of tolerance anyway. Best bet is to clean them with something none abrasive and then check the weights. If they are good probably best to leave them. If they are already out, make them pretty and get precision weights for them. The actual weight is not as important as knowing what the weights weigh.

 

[crazyjim30]

As promised, here's a picture of one of the weights. The condition is typical of the entire set.

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[Leaflessshadetree]

My guess is brass and they are tarnished. Not a clue as to how that affects the accuracy.

 

[gte718p]

My guess is brass and they are tarnished. Not a clue as to how that affects the accuracy.

I would tend to agree accept it looks like rust around the seam at the bottom left. That would make me believe plated alloy.

Unless you are looking to do some crazy metrology stuff, it should not be an issue. Definitely will affect accuracy, but not much.

 

[crazyjim30]

Nope. No crazy metrology stuff here. My instructions were, "Make it work". My pride says, "Make it work right."
It was donated to my school and was more or less collecting dust in a corner until our program head came up with the idea to build a calibration and process control lab. I think he'd be better off buying a new educational setup directly from a manufacturer, but no one listens to me around here.

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[crazyjim30]

After soaking the weights in vinegar, this is the result. I don't know what kind of Dupont funk was on these things, but it actually produced a layer of white foam on top of the vinegar.

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