If any of my pattern instructions involves stitching a corner, inevitably one or more of my testers would tell me, “you forgot to say ‘clip seam allowance’ in the step.” That’s what I love about my testers. These ladies are detailed and diligent. I cannot express my appreciation enough for their help.
(This post contains affiliate links.)
However, back to the topic, I don’t actually clip seam allowance when I stitch a corner in some circumstances. It is because sometimes the corner is sharper without clipping, especially when there is only one seam involved (no intersecting seams).
This is the process I go through, demonstrated using the Lisbon Cardigan, which will be released very soon! In this case, I am using a knit fabric and a serged seam, but it’s equally valid using a woven fabric with a regular stitched seam.
Here is one seam. It is currently folded over itself with right sides together.
Fold the seam allowance in.
Use your thumb to hold the folded seam allowance while putting your index finger between the two layers of fabric, like you are pinching the layers of fabric.
Turn the fabric right side out. Here’s the slow mo.
Turn even more.
Tidy it up a bit. The seam allowance acts as something more sturdy to “push” the corner into something shaper.
Here you go! You have a sharp corner.
Some seamstresses do not even clip the collar points on their shirts. In his book, Shirtmaking: Developing Skills For Fine Sewing, David Page Coffin, talked about the method that Adriana Lucas uses in her custom-shirt workshop (page 106). There’s no clipping of the corner involved, even at a corner as tight as the collar point. This handy tool called the hemostats is used to facilitate the process. Here is David Page Coffin’s post about this method.
When you clip a corner, you remove some fabric so that the stitch line is very close to the raw edge. There’s the danger of poking through the stitch line when you turn the collar. The beauty of this method is that, with the seam allowance intact, that risk is low.
I tried this method and it produced great result. However, I don’t continue to use it because it uses sewn-in interfacing that you cut away at the seam allowance. I use fusible interfacing that goes all the way to the cut edge. Without being able to trim the interfacing, the corner is more bulky. Also keep in mind that David/Adriana uses 1/4″ seam allowance for the collar.
But I do learn something. The underlying reason for a dull corner is that the seam allowance is unruly inside. If you can manage to straighten and maintain folded and orderly seam allowances after turning, you can have a very sharp corner.
I am not against clipping though; in fact, I do that all the time. I evaluate the situation, and go with the method that gives me the best result. To me, that’s what sewing should be. It’s not about following instructions strictly, but thinking and experimenting.
Hope this is helpful!