Sometimes people find it difficult to get the mitered corner to exactly match up to the hem layout.
Here are some tips:
It is important that the distance between the withdrawn thread line for the fold and the withdrawn thread line for securing the hem is the same on both sides of the corner.
Iron your piece and lay it flat – right side face down.
Follow the thread of the withdrawn thread line for securing the hem up to where it meets the withdrawn thread line for the fold, mark the point exactly. Do the same on the adjacent side of the corner.
Using a #2 pencil draw a diagonal line to connect both marks.
Now there are two different ways to proceed.
Fold the piece as shown in the picture below.
Insert a pin along the pencil line.
To make sure that you have folded the fabric exactly, turn the piece over to check that the pin is also lying directly on the pencil line on that side of the fabric.
Sew along the pencil line then trim the seam allowance.
Turn the hem corner right side out. A pair of scissors with points that are not too sharp can help to define the corner point.
Fold the raw edge along the fold line. First pin and then baste the hem in place.
Secure it using Antique Hem stitches.