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An electrically insulating hard finish for steel

I need a small, precision sleeve/bushing to use while press-fitting an electrically conductive cylindrical metal part into another electrically conductive metal part, while providing electrical insulation between the two parts.

In other words, I need a hard precision tube which is an electrical insulator. I looked through McMaster Carr's catalog and I was unable to find any ceramic tubes of the proper dimension.
However, there is an excellent selection of stainless steel tubes that I could use, except, of course, that stainless steel is a fairly good electrical conductor.

Is there some hard, abrasion resistant finish that can be applied to stainless steel to make it an electrical insulator? The finish should have the minimum possible effect on dimensions and should be as inexpensive as possible. I was reading about black oxide.

I couldn't find the conductivity of black oxide, but one finishing company's website said that it is actually conductive (or, rather, that it reduces the conductivity of the metal by less than 1%).

I would appreciate any suggestions or ideas you may have.

Erik Reuter
fiber optic components - Somerset, New Jersey
2003

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I am interested in finding the answer to this question too. Please let me know.

Thanks.

Prashanth Holenarsipur
medical systems - Milwaukee, Wisconsin
2004