Grading seams involve cutting the seam allowance at different widths so that when your project is pressed to the right side it eliminates bulk and results in a flat seam that sits nicely.
Grading Seams That are Bulky Tutorial
Are you having problems sewing bulky seams? Grading seams and grading seam allowance are especially important when you are sewing thicker fabrics in your Winter sewing patterns, and they will make your sewing projects look more professional. Reducing bulk by layering seams will give a smoother finish on the outside of your garments.
What is Grading Seams?
Grading seams is a sewing term that refers to layering the seam allowance in order to reduce bulk in thick fabrics. Because it reduces bulk, it gives a professional look on the outside and a more comfortable fit for clothing.
Where to Grade Seams?
When sewing, grading seams only needs to be done where you will be pressing the seam to one side or in an area, such as a collar or cuffs, that will be turned right side out. It is not necessary for straight seams that will be pressed open.
Grading Seams Instructions (How to Grade a Sewing Seam)
Here are the step-by-step instructions for grading your seam allowance:
Step 1 - Sew the Seam
Start by stitching your seam as per the sewing pattern instructions. This seam had a seam allowance of ½ inch (12mm).
Step 2 - Trim to Grade the Seam
Use small scissors to grade the seam allowance by trimming one of the layers of seam ⅛ inch (3mm) narrower than the other.
Where you have a curved seam line(eg necklines or armholes), grade first before clipping the curves.
In this example, I had 2 layers of fabric, so I left the outside seam allowance at ½ inch (12mm) and trimmed the other at ⅜ inch (1cm).
Always be careful not to trim too close to the stitch line when you have fabrics that fray badly.
Step 3 - Finishing
As the seam allowance is now in layers you will need to finish them separately. Use a seam finish that does not add bulk, such as using pinking shears.
Step 4 - Press the Seam Allowance
Once you have graded the seam you can press it to one side. I always like to press so that the wider layer is on top and covers the narrower layers underneath.
How to Grade Seams with Multiple Layers
When grading seams where you have more than 2 layers, grade the seams to 3 different layers.
You may need to grade a couple of layers to the same width, so you are not cutting right back to the seam allowance.
Grading Seams with Intersections
Where you have 2 seams that intersect such as the underarms area, trim the ends of the seam into a point to reduce bulk.
This way when you press the seam open, there is not 4 layers at the intersection of the 2 seams.
Here you can see how it looks when the seam is graded at an intersection. This will sit much flatter in your final product.
What Does Layer Seam Mean?
Layering a seam is just another term for grading of the seam allowance. This means cutting the excess fabric at the seam in different layers in order to reduce bulk. This is important when using thicker fabrics for garments that you want to look professionally finished.
Grading Seams FAQs
What is the difference between trimming and grading?
Trimming a seam allowance is done through all layers. For example, if the instructions say to trim the seam to ¼ inch then you will cut through both layers. Grading, by contrast, means layering each side of the seam in order to reduce bulk.
What scissors are used for grading seams?
If you are grading your seam on the odd occasion, just use a small pair of scissors that are sharp and easy to control. For regular grading, you should use a pair of duckbill scissors. These scissors have an oversized curved bottom blade that is used for applique.
How to grade seams on facings?
Because facings are curved, you will need to reduce the seam allowance in layered tiers in order to reduce bulk. Trim the first seam allowance layer to ⅛" from the stitching line. Take care not to cut through the stitching. Then trim the second layer ⅛" from the first layer.
Other Meanings of Grading in Sewing
When used in conjunction with sewing patterns, grading means to size up or down in order to get a complete set of sizes. For example your sample pattern may be a size 8 and you will use grading rules in order to get the larger and smaller sized patterns. This means you don't have to start from scratch to make a pattern for each size.
Grading Seams - In Conclusion
So next time you need so sew a thick seam or intersecting seam, take a little extra time to trim and grade the seam for a professional result that will also be much more comfortable to wear.
What are you planning on sewing this season? Do you have any extra tips for sewing bulky seams?
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