This is something that I've wondered about.

I generally have set up planes so that the frog in the same plane as the back of the mouth, so that the iron is supported there,

but to get a close mouth opening, the iron is supported only by the frog, about 5/16" back from the cutting edge in this example, and the chipbreaker/cap iron are in effect flexing the iron down.

What's the deal?

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