Trimming, grading, notching and clipping
Eliminate bulky seam allowances by clipping, notching, and trimming seams in specific areas of a garment. And achieve a flawlessly pressed finish on curves and points in the process. In this article we’ll talk about how to much fabric to trim and how to efficiently reduce bulk.
Of course, every garment and fabric can lead to different results so you will learn to use your intuition to combine these skills for the best results. The best practice is to test out on scraps first if you are unsure before cutting into your actual garment, for example if making your first coat, check how bulky your seam allowances will be on chunky wool or on a silky blouse, check the seam allowance won’t show through in an unsightly way.
Trimming and grading
Trimming and grading are used to reduce bulk. With trimming you are cutting back excess fabric most often from the seam allowance, in a specific area. Grading helps you layer the thickness of fabric at the seam allowance to disguise the bulk on certain seams.
For grading, trim one half of the seam allowance to half its width. I like to use duck billed scissors also known as applique scissors because one blade has a large plate shape that pushes the underlayer of fabric out of the way safely and avoids unwanted snips.
Pressing your seams open is a great way to distribute bulk evenly to each side. But when multiple pattern pieces are joined together, trimming and grading helps eliminate bulk at the intersection of seams. This is especially helpful at the underarm area and between the legs on the curved crotch seam where the seams aren’t pressed open.
It’s very helpful to trim is the small square area created by two seams intersecting. Here you trim at a 45 degree angle to remove small triangles of seam allowance caught in the intersection. And if the intersecting seam will be pressed in one direction, rather than open (for example at the waist seam) consider grading the seam allowance behind to half.
How you will trim or grade can depend on the finish of your garment, for instance whether there is a lining or facing and the internal seam allowances will be left raw. In this scenario you can reduce bulk by trimming one side of the seam allowance to half. Perfect for collars and cuffs, and necklines.
When working with heavier fabrics you can also reduce the bulk created by any darts by cutting them open along the length, stopping a few mm from the tip, and pressing open the bulk.
The most common issue I see is people failing to trim points correctly on collars, cuffs, waistband ends or pocket corners. Grade the seam allowance first, then trim the point to at least to a 50 degree angle. Commonly people just snip off at 45 degrees but that’s not enough!
Similarly you may want to grade the seam allowance from the hem area to allow for smoother folding up of the hem. Start the grade just below where the folded edge will sit.
Clipping and notching
Ever sewn a beautiful curve and then tried to press the allowance flat, and ended up with a lumpy seam? The seam allowance needs a few careful snips to lie flat and there are different methods for clipping convex (for example on princess seam) and concave curves (around a neckline).
Don’t forget, you can grade a curve before you clip or notch it!
Notching
Convex curves are found on rounded pockets, peter pan collars and some styles of curved hems. But you may not have realised that on these designs, the raw edge of the seam allowance measures longer than the seam line you’ve sewed. So when you try to press the seam flat, you have excess fabric in the way. Notching will remove the excess and help you press a smooth curve.
Using small scissors, cut small triangles out of the allowance. The tighter your curve, the closer together your notches should be. For a gentle curve, notching every few cm should be enough. Ensure the lowest v point of your notching is still a few mm away from the stitching line so you don’t weaken the seam and risk fraying. Around armholes you will need to make several notches in the seam allowance and then trim any seam intersections (keep reading).
When pressed to the right side, the notches will close up slightly but not overlap, keeping the seam neat on the outside.
You may also be asked in your pattern instructions to clip into the seam allowance of a bulky single pressed hem or curved hem to hem you press up the allowance. Imagine the curved hem of a man’s shirt or thick brocade flared skirt.
Clipping
I often see people notching concave seam allowance around necklines. All you need to do is clip into the allowance so it can spread! But there’s no harm in notching instead of clipping. Start with a clip at the bottom of the curve (or v point), for example the centre front point of a round neckline then work evenly out to each side.
You can still understitch an already clipped neckline; don’t fight the gaps in the seam allowance and stitch a few mm away from the seam line as you normally would.
When pressed to the right side the snips will spread to create a neat curve.
On a princess seam you will use both methods. The front bodice is formed of a concave curve and the side front bodice is a convex curve. When sewn together one side of the allowance will be too tight to press open and the other will have too much excess. Notch and clip the curved area to allow the seam to press flat and the bust shape to be created.
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