"Doug White" wrote in message
...
I need to lap the ID of an aluminum piece out about half a thousandth.
It is heavily annodized, and has a matte, frosted finish. I think the
reason it is undersized is that the annodization built up more than
expected.

I have an expanding brass cylinder lap that fits fine, but I'm wondering
what sort of abrasive I should try. Given that annodizing itself is very
hard, I don't know if normal compounds will touch it. I'm also not sure
how fine I should start with. This is a one-off, so I don't want to have
to go out & buy several grades of diamond paste. I have a "sample" kit
of Clover lapping compounds, which includes silicon carbide, and possibly
aluminum oxide.

Any suggestions?

Thanks!

Doug White

Silicon carbide is far harder than aluminum oxide and will easily remove the
amount you desire.

If it was up to me, I'd use a Sunnen hone with a fine silicon carbide
stone-----or diamond if I had it available.

Harold