How do I cut trim molding in a corner?

Question

How do I cut trim molding in a corner?

Answer 1

A chop saw is the best way to cleanly cut rough miters, though I made do with a hand miter saw and used a table saw on short pieces. But you almost always end up doing some hand work to make it look right. I'll explain this below.

If you're installing baseboard the walls are almost never a perfect 90 degrees at the corners - certainly not by the time they're beaded and mudded over. This is true for both outside and inside corners, but it's especially true for outside ones.

For outside corners there's a way to measure and transfer the exact angle using a slide bevel. This frankly speaking is tedious, so what I do instead is cut the mating pieces slightly long - 1/16" or so, then undercut the miters with a chisel. I then hand-fit the pieces by filing down the miters until the corner fits flush. The trick is to make just the miter outer edges touch.

For an inside corner, use a coped joint. This gives a nice no-gap look to the finished joint.

Here's how you do it. One side is just cut fIush to the inside corner - snugly, make it a tiny bit longer. The other side is "coped", that is, cut to shape to meet the first piece. You do this in two steps: first, cut the piece at an inside 45 (cut facing out), then cut away the outline along the trim's shape, using a coping saw, jigsaw, round file, etc. Again, the piece is test-fitted as you go along to refine the joint.

These two techniques take a bit of practice, but the result is worth it.

Answer 2

Depends on the molding and the corner. If its facing something then cut at 45 degrees.  

Answer 3

I think before anyone can answer that, they would need more information,

What kind of trim. Baseboard,quarter round, Crown etc.

Most are cut using a miter box and a back saw available at walmart or most hardware stores. Or if you have to cut a lot of trim a compound miter saw is a must.  

Answer 4

You can use a chop saw or a coping hand saw