How do you measure for miter cuts on trim work?

Question:

Answers:
Actually in lots of cases, you don`t even need to measure. Let`s say your trimming a door. If you need a 1/4 inch reveal mark it in the top corners and several points down each jamb. If your doing a lot of trimming, a small pocket tool just for this purpose can be purchased a Lowes and HD. I have a home made one that I can mark 1/4 and 1/2.
Here`s the easy part. You have 3 pieces of trim(one for the head, 2 for the jamb legs). Hopfully they are of a manageable length.
Make a right hand 45 on 2 of them. set them to the right of the table. Now make a lefthand 45 on the remaining piece and set it to the left of the table.
Take one of the rights and place it on your markes on the head of the door and transfer the mark on the uncut end. Unless someone messed with your saw you should still be set to make this cut.

Attach head trim to marks.
Take the other 2 pieces and place the at the correct sides and flip them upsidedown. Scribe a mark on these pieces at the top of the head trim and cut them a 90.
It`s pretty once you figure it out, and quick.