How do I identify the metal from which that this nameplate is made? It's from a WW2-era lathe. Is behaves somewhat like lead, but is harder.
My father and I are restoring a South Bend 9 model A
, a really classic lathe, for my future use. My current work is restoring the various data plates
on the thing that show you how to operate it, gear ratios, etc. At first glance they looked like aluminum, but upon closer inspection I'm fairly sure they're not.
Pictures, all with reflecting light to show the luster and with white/black objects to give approximate color:
* reflection on polished raised letters
* reflection on dull gray body
* the object shown used to have a paint-filled body with the polished letters standing proud above the paint. The paint was almost entirely gone and I was able to lightly flake off what was left in the corners. It was cleaned with denatured alcohol (which just got off some gummy residue in the corners). I swiped it with lacquer thinner, too, but nothing came off.
* the polished raised letters are about as shiny as polished aluminum, but the material is softer than it should be; I've welded and formed a fair bit of aluminum and this feels wrong.
* everywhere there's a scratch or wear (such as on the edges of the letters) the material has turned a dull gray. This rules out it being aluminum.
* it's too hard to be lead (I've worked with rolled lead sheet and lots of solders) but the corrosion/color looks just like it, honestly.
* the lathe body is stamped JAN (Joint Army-Navy) and was manufactured in 1943.
* All other South bends I've seen used brass plates with this exact same same chemical milling (etching) style. I'm guessing the scarcity of materials during the war necessitated this plate being something cheap and available.
* it leaves a metallic smell on my hands after I handle it for a while. It's not "stinky penny" smell, but definitely metallic.
My best guess is tin, but I'm not sure how to narrow it down. I've kept up my electrical engineering skills, but my chemistry and materials classes have receded from memory. I have the usual battery of household chemicals available for testing, up to hydrochloric acid and copper sulphate. I've other tools like power supplies, welding tools, and such, if that helps.
This is pretty much an academic exercise, but given the neat, traceable history of the lathe (e.g., it was used post-war to make jukebox parts!), it would be nice to know the material so it can be part of the machine's story.
Help me, MetaFilter, you're my only (metallurgical assay) hope.