One for the pro polishers (NLC)

[BiggestNizzy]

I have a 22 (7/8") dia hole in a metal part made of super duplex (stainless) it has a detail (like a bell mouth) 100mm (4") down this hole that needs to be polished to a surface finish of 0.4 ra (16 Ra)

Does anyone have any idea's what I can use ? the usual scotchbrite is out of the question.

[DavieK]

Might be worth asking on detailingworld.com, you can get hold of stuff for lapping in mechanical seal faces that would probably do, braso might be worth a try if the surface is already pretty good?

[Mikie711]

You might find this chart useful in deciding the level you need to go too. Basically that number relates to a surface finish equivalent to using 240 grit paper. Shouldn't be that difficult to achieve. I would have thought dremmel with a polishing mop and some compound or a fine grit lap wheel would be the easiest route.