1. Seams and Seam Finishes
Apparel 1 Obj. 3.03
Supplemental PowerPoint

2. Seam Allowance
Standard seam allowance is 5/8-inch. If the guide sheet doesn’t specify a seam allowance, then assume it is 5/8-inch.
The guide sheet will tell you what seam allowance to leave.

3. Fabric notes
Unless the guide sheet tells you something different, fabric is placed right sides together.
On all plain seams the fabric is right sides together.
Remember the plain seam is:
Fabric right sides together
Stitch, leaving a 5/8-inch seam allowance
Press the seam allowance open

4. Drawbacks to the plain seam
The plain seam is the weakest of seams.
Because the seam allowance isn’t finished, it is likely to ravel. That means the seam will eventually come apart.
All stitches should be backstitched at the beginning and end to keep them from coming apart.
Backstitching is sewing backwards at the beginning and end of a stitch to “lock in” the stitch.
The backstitch should not show as it does here. It should follow the same path backward and then forward.

5. Making a seam stronger To make a seam stronger it can be reinforced.
Reinforcing a seam means the stitch length is shortened to 15 to 20 stitches per inch.
These shorter stitches make the seam stronger.
Crotches of pants or shorts, underarms of shirts and other high-stress areas should be reinforced.

6. The Zig Zag
The zig zag stitch is used on medium and heavy weight fabrics. It will pucker and damage lightweight fabrics.
The zig zag is used as a seam finish to prevent raveling.
It’s advantage is that it is fast.

7. Turned and stitched This is the dinosaur of seam finishes.
Used occasionally on the hems of dress shirts and in applications with see-through material.
In this finish the seam allowance is turned back ¼-inch and then stitched at the edge.
It’s purpose is to prevent raveling.

8. Importance of pressing
All well-made seams are pressed after stitching.
Pressing the stitches into the fabric helps set them.
Pressing the seam allowance open lets the seam lie flat.

9. Seam finishing and machines
Sewing machines and sergers can both do seam finishes.
The serger stitches and finishes at the same time.
Stretch fabrics and knits are especially well-suited for serging as a seam finish.