Mitred corners provide a more attractive finish on the sewn edges and corners of any sewing project. A little folding, trimming and sewing will create a tidy edge with a 45-degree hem corner. From napkins to jacket edges, mitred corners will neatly, and professionally, finish corners and remove excess hem bulk so your edges will lie flat.
Adjust your hem allowance to 1 1/4 inch at the square corner edges of any sewing project where you want a crisp clean 90-degree corner with a 45-degree mitred hem on the wrong side of the fabric.
Fold and press a 1/4-inch finishing hem, folding so the fabric sits wrong side to wrong side, on both edges of your corner. Folding the fabric over will hide the unfinished edge of the fabric and give a crisp edge to your hem.
Fold and press a 1-inch hem, folding so the fabric sits wrong side to wrong side, on both edges of your corner.
Unfold the 1-inch hem on both edges of your corner. Place your fabric wrong side up on your table.
Fold one 1-inch hem back over and mark with your disappearing ink fabric pen where the edge of the hem meets the edge of the fabric on the other corner. Unfold the hem. Repeat for the other corner edge.
Draw a straight dotted line joining both edge marks through the 1-inch hem crease where the creases from both edges intersect.
With the 1-inch hems open, fold your fabric, right sides together, from the corner, so that both corner edges are aligned and your dotted lines and edge marks line up. Pin the fabric together to keep your fold in place.
Sew the fabric together along the dotted line.
Trim the corner fabric removing all but a 1/4-inch seam allowance.
Press the seam open.
Reverse your corner and use your straightedge corner to push the fabric into a crisp, 90-degree corner. Your corner should have a 45-degree sewn hem directly at the corner on the wrong side of the fabric and the 1/4-inch hem should be turned under for a crisp edge.
Sew the hem down, 1/8-inch away from the folded edge of the 1/4-inch hem, all the way around your corner. Keep your needle down when you turn your fabric at the corner to make a crisp turn.
You have now completed one mitred corner! To finish additional 90-degree corners on your sewing project with a 45-degree mitred hem, repeat steps 1 through 12.
Before you trim your corner seam allowance, test-reverse your corner to be sure you sewn it in the right direction. Adjust the hem width by making changes to the size of the 1/4-inch folded hem and the 1-inch folded hem, making them larger or smaller as desired.