I just ordered the TEKTON 3/8 Inch Drive Deep 6-Point Impact Socket Set, 37-Piece (1/4-1 in, 6-24 mm) on Amazon, it was delivered with each socket heavily lubricated (with what looks like oil). There was a cardboard piece in between both ends of the case, and it was pretty wet. You can find the data sheet for it here which shows the set is made from Chromium-Vanadium (Cr-V). Does this need to be lubricated or stored lubricated? Ths spec sheet above also says,

  • "All pieces have a corrosion-resistant manganese phosphate coating."

It sounds all the more like this shouldn't be neccessary, but I'm wondering why they did it then.

  • Black is traditional for impact sockets, that's probably why they went with manganese phosphate finish
    – Jasen
    Aug 2, 2021 at 11:43
  • 3
    I'm not sure why my comment was removed. It was justification for my close vote. This is a matter of opinion. Oil is applied because of extended shipping and storage periods. Whether you retain such a coating is entirely up to you and your use case. "Corrosion resistant" is not "corrosion proof".
    – isherwood
    Aug 2, 2021 at 18:54

3 Answers 3


I store all of the tools used on my car with a very thin layer of oil - usually after using them they get a bit dirty so wiping off with a clean rag leaves enough to protect them.

I do not clean them with degreaser and leave them "dry" and unprotected.

Note, many metal items that are subject to long transport or storage times are shipped with a protective coating, this includes brake discs as an example. This needs cleaning off before use.


I asked this question to Tekton myself. I was mainly interested in knowing if corrosion, and not galling, was the reason for this coating.

Q: These sockets came coated with some kind of lubrication, what is it? What's the purpose of it anti-galling or anti-corrusion? Can it be removed?

Here was their response,

A: This is Nate from Tekton. These impact sockets ship with a coat of lubricant as a corrosion prevention measure, and we recommend that you maintain the sockets with a lubricating oil. If you remove the lubricant, it will not affect the performance of the sockets, but it will make them less resistant to rust.

So I take it that galling is not a concern here.

  • Actually resistance to galling is improved by the phosphate coating because it retains an oil film. Q & T steels of moderate hardness ( such as your tools which I assume are roughly Rockwell 30 = 150,000 psi tensile) , are subject to galling under some conditions which your tools are unlikely to experience. Overshare; Higher strength oil field casing threads are prone to galling if not similarly coated. Aug 3, 2021 at 0:57

The manganese phosphate ( "conversion") coating gives some corrosion protection for mild service. Tools are "mild" service , normally dry and oil coated. So they should be fine unless you use them in salt water. The Cr-V is an ordinary low alloy steel, so has about the same corrosion resistance as carbon steel.

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