Casing Trim Cutting Tips and Tricks

This instructable describes one geometric method of installing door and window casing

Step 1: Mark

Mark the door corners where the casing will meet and then mark the height on the vertical casing.

Step 2: Cut

Cut 45 degrees at the marks on the vertical casing pieces

Step 3: Cut Top

Cut a 45 on one side of the top piece then hold up to the vertical miter to see if the angle needs to be modified.

Step 4: Re-cut

Slightly adjust the saw and recut the miter of the top piece so that the miter is perfect.

Step 5: Opposite Side

Cut a 45 on the top casing for the opposite side, but don't cut to length. Also make an adjustment until the angle is correct. Leave the saw at that angle.

Step 6: Cut to Length

With the saw at the correct angle, cut the top piece to length.

Step 7: Dry Fit

Dry fit the miter.

Step 8: Nail

Nail in place

Step 9: Complete