Trimming a curve

[SavannahLion]

I've been kind of racking my brain on this one and I can't work out how to do it short of doing it by hand. I thought about using a hand planer or file but those would result in an uneven edge and shred the edge anyways. It needs to be cut.

I'd like to trim off an edge (because it's too deep and uneven). In the really bad sketch below, A shows a cross section, the red portion is what I want cut off. The gray/brown areas are what I want to keep. B shows the edge if you were looking straight on. It's curved. I fiddled with a router, but since it's not on a flat surface, it's a little on the wobbly side and most likely not the brightest thing to be doing with a high speed tool.

So... any ideas? Is there a bit or tool that can let me use the brown surface as a reference and cut the gray area?

[t3design]

How thick is the part you want to trim off?

It looks like you could block up the piece with supporting blocks under the brown part with the red part down, then use a dado blade set in a table saw or a plunge router bit in a router table to "mill" off the material by rotating the piece as you push it through to keep the edge in the blade area.

t3

[Octo]

That would be my suggestion too. Set up a fence on a table saw and pass it through. Norm Abrams does it all the time.... 

[SavannahLion]

How thick is the part you want to trim off?

It's dark and it's out in the shed, but off the top of my head I think it's about 1/8" maybe 3/16" or thereabouts. I don't think it's over 1/4". I erred and drew the picture a little bit out of scale.

That thin edging is probably going to be destroyed with a dado blade. I haven't bought one (I have a couple I got from my father though) and I recall their teeth being pretty large (again, out in the shed), and I hear they're pretty pricey if I was going to go after some finer teeth.

I don't understand how I can use a plunge bit in a router table like that. not that it matters, i don't such a table