Science of Sewing: Finishing Seams without a Serger

Fraying seams are the worst. They’re scratchy and uncomfortable, they can leave threads hanging out from under you clothes, but worst of all, they can be unstable, cutting the life of your garment to nothing in a flash. Here a few different ways to finish a seam that will increase the longevity of your garment and put an end to unseemly seams!

Basic Straight Stitch Seam

The simplest way to finish a seam is to sew a parallel stitch to the seam to keep the raw edge from fraying.

To do this, sew your seam with the seam allowance instructed by your pattern. Then sew the selvage of your seam ⅛” from the raw edge. You’ll want to use short stitches to give the seam reinforcement.

NOTE: This seam will still fray, though not nearly as much if left completely unfinished. It’s recommended to use this seam finish on hidden seams.

Pinked Straight Stitch Seam

To prevent more fraying from the Basic Straight Stitch Seam, you can utilize pinking shears. You’ll follow the same steps as the previous seam, but sew ⅛” from the seam instead of the raw edge. Then cut the seam allowance away with the pinking shears.

I actually highly recommend this seam finish for armholes of sleeves as it reduces bulk, is reinforced, and is a very flexible seam in a curve.

Zig Zag Stitch Seam

Sew your seam with the seam allowance instructed by your pattern. Then simply run a short, wide zig zag stitch along the edge of your fabric to encase the raw edge and prevent fraying.

This is not the prettiest of finishings, nor is it the most comfortable. It will stiffen the edge of your seam, so it is best to use on garments that are not close fitting to the body.

Clean Finish Edge

Sew your seam with the seam allowance instructed by your pattern. Then press the seam open. Once cooled, press the edges of the fabric under 1/8″-1/4″ to the wrong side and stitch into place.

Back side of the seam allowance shown above.

The finished product of this seam is very clean and comfortable to wear. It does produce some bulk at the seam, so use with lighter weight fabrics.

French Seam

This seam is very common in couture sewing on parts of garments where the seam is exposed. More importantly, this is THE best way to sew seams for fabrics like chiffon, voile, and organza as it makes them very strong. The French Seam completely encases the raw edge of the seam.

If using a standard sewing pattern with a ⅝” seam allowance, do the following:

  • Sew WRONG sides together at ¼”
  • Press seam to side and then out.
  • Sew Right sides together at ⅜”.

Voila! A completely encased seam.

Mock French Seam

Another way to encase a raw edge is to do a Mock French Seam. The seam works well for curves as you can clip part of the seam allowance to add in the flexibility you need. This finish can get chunky, so be sure to use it on light- to mid-weight fabrics.

  • Sew RIGHT sides together with your pattern’s seam allowance
  • Fold the raw edges into the seam line and press
  • Put folded edges together and sew the folded seam allowance.

Flat Felled Seam Finish

This seam finish should really be called the Jean’s Seam! You’ll primarily find this seam on the inseam of jeans as it’s rugged, durable, lays flat, and is basically the most baller seam out there. Can you tell I love this seam finish?

  • Sew WRONG sides together using the pattern’s seam allowance
  • Trim ONE side of the seam allowance in half and press the seam open
  • Fold the other side of the seam allowance so that the raw edge meets the seam line.
  • Fold the longer seam allowance over the cut seam allowance, you want to tuck the raw edges in.
  • Stitch the seam in place, aka felling it.