in case something doesn't fit right and you have to remove the trim to recut it. Miter and Mark the Top Casing Cut the corresponding angle on the top casing, leaving the opposite side at least 1 ...

But a regular 45-degree miter won't fit even now because the molding has to tilt down to meet the jamb. Correct this problem by tilting the trim on the bed of the miter box to match the angle at ...