When installing decorative trim in your home, part of the job is cutting the trim to turn corners. To turn a 90-degree corner you must cut the two adjoining pieces of trim each at a 45-degree angle. To ensure an accurate cut, use a miter box and a back saw. A miter box is a open-top U-shaped box with saw guides on the sides for both left and right 45-degree cuts, as well as a straight 90-degree cut. Using the miter box as a guide when making your cuts ensures that trim is always cut to a precise and uniform angle.
Things You'll Need
Measure the length of the trim needed, then mark the trim using a pencil.
Determine whether you will be making a 45-degree left, 45-degree right or 90-degree, or straight, cut.
Align the trim with the two guide slots for the appropriate degree and direction cut.
Insert the back saw into the guide slots, then lower the blade to the trim to align the blade with the trim.
Use deliberate and steady passes with the saw to cut the trim.
If you are unsure if a left or right cut is needed for the particular piece of trim that you are using, make test cuts using scrap pieces of trim.