Tuesday, January 3, 2012

Flat-felling a curved seam

Flat-felling gives such a nice finish to tailored items, but if you try it out on a seam with a bit of a concave curve happening it can end up looking messy and not much of an improvement to the looks of the garment after all!
I wondered whether running a line of gathering stitched along the seam allowance might help to solve the problem of turning under that excess fabric around the curve and help it sit nice and flat.  So I tried it out on the sleeve cap seam allowance of the next shirt to roll out of the atelier, Craig's birthday shirt, and it worked like a charm... I did take some pictures to illustrate but unfortunately a couple seem to have been lost in a recent computer clean-up  :(( so for the missing pictures I shall attempt to explain as best I can... :D
The sleeve cap  has been attached flat to the body of the shirt, and the sleeve and side seams of the shirt are still unstitched.  I want to flat-fell the seam allowance along that top curve of the sleeve cap.  The sleeve cap seam has been pressed up towards the body of the shirt... 
Lift up the top layer of the seam allowance and snip the underneath allowance to just less than half its width, just as you would with a straight flat-felled seam (tutorial for that here)...
Now run a single line of gathering stitch along the wider upper curved seam allowance, at the halfwidth line.
Now turn under the raw edge along the line of gathering stitches, treating the line of stitching as the fold line.  If the curve is not very pronounced, the gathering may only need to be pulled in just a little...  Distribute and ease out the gathering as needed to achieve a flat a finish as possible.
Press and pin in place.
(missing picture here, sorry)  I topstitched the seam allowance down from the inside of the shirt; taking great care to keep the topstitching a perfectly even distance from the seam stitching, that is using the seam stitching as the guide to gauging the width of topstitching.  If you forget this and aim to topstitch using the folded edge as your guide, it may end up looking a little uneven on the right side (because not even the most careful of us is Perfect at folding under and pressing  an exact width fold), and this you want to avoid.  After all, the appearance on the outside of the garment is what counts!
To illustrate; here is the underarm at the 4-corner point where the sleeve seam meets the side seam: Below; inside the armhole, that flat-felled edging has a few little bumps along that folded edge because of the allowance not turning under completely even-width so doesn't appear super perfect.. 
but below; the outside does.  So I'm OK with that...
(another missing-in-action shot, so below is an "after" shot) Now I stitched the sleeve and side seam in one go; and flat felled this seam allowance.  
Because this seam here is a convex curve the seam allowance has less fabric along the raw edge than the seam, (rather than more fabric as in for a concave curve) and so it folds under more easily.  However because there is less fabric, you need to stretch out the seam allowance a little when flat-felling it down.  In my experience this is a lot easier to achieve than dealing with the excess fabric in a concave curve, but very rigid fabric may either need a bit of a snip around very tight curves, or alternatively a HongKong finish may be more suitable.
(Hmmm, diverted a little into mathematics territory there, but I hope that helped to illustrate the point!)

I don't know I would bother with flat-felling the side-and-sleeve seam of a long sleeved shirt,; sewing neatly up the inside of a long tube is probably high up the list of things that are disproportionately difficult with consideration to actually how much it really improves the look of the shirt... but I've found sewing up the inside of a short-sleeved shirt to be OK and not too much of a hassle.


  1. Your seams are perfect, and both photos and description are clear and beautifully presented.
    I am a convert to a flat felling foot. Curved skinny seams can still be tricky, but those inside-the-long-sleeve seams are a breeze (and vitally flat felled for my fellow,who likes to wear them rolled up)

  2. You do lovely work and your detailing is always perfect. Thank you for showing me how to deal with curves when flat felling seams.

  3. I have just 'attempted' to flat fell a short sleeved short for myself, and was pleasantly surprised at the results. Love your version and explanation - will be saving this for future reference...

  4. If I ever get the nerve up to try this, I will definitely refer back to this post with all the helpful pictures!

  5. Great tutorial - very clear and consise and not to mention great photographs to illustrate. I know I've done a flat felled seam on a long sleeve shirt before when I was at Tafe - but haven't done it since!

    Thanks for your comment on my pattern haul. I've redone the pictures - taken them from the BMV site so that they are much clearer to see now.
    I'm a lousy photographer!

  6. I wonder if you have tried Margaret Islander's method for flat fell seams? The fabric is offset for the first pass, then flipped over and the raw edge encased. It is quite easy and fast, but flat fell is always more difficult in curved or small spaces.
    I just discovered your blog and it is a delight. Your sewing is wonderful to see.

  7. I love this tip. I'll have to try it when I get around to actually sewing for Q.

  8. Clever! Brilliant tip! This is where my I let myself down. I can't be bothered with such details. But then I get disappointed with the things I make. Need to pay more attention to detail. This can be my New Year's resolution.

  9. Thanks for this! Definitely bookmarking this for later use.

  10. Brilliant! That line of gathering really would make a difference.

  11. Thank you for another excellent tutorial. Your photos are so very helpful. It makes a lot of sense to gather the wider seam allowance. I have a chambray shirt on my project list (already have the fabric) and will be sure to try out this technique.

  12. Great trick there Carolyn - and one I will be adding to the arsenal. Thanks!

  13. Thanks for the tutorial, Carolyn! This'll go into my "smart stuff" box. :)

  14. Nice! The pictures are very helpful! I have never tried it this way and it looks like it would work a lot better than my previous attempts.

  15. I for one love mathematical diversions! :) I've wondered how to do this - I would have snipped the convex ones but would never have thought of gathering stitches for the concave ones to make it lie flat. Genius. Maybe next round of shirts for the boys I will try this out. Wow. I would feel like a really smart seamstress then ... I think it was from you that I first learned hong kong finishes too, and have used them since to good effect .... Happy New Year!

  16. Love the shirt. DD asked for a double sleeve shirt so the tutorial comes in handy.

    At AGU, I met an Australian scientist who feared that the heating in the Indian Ocean has permanently changed the Perth climate. You are not in a temporary drought; lower rainfall is your new normal.

    The same goes for East Africa.

    The monsoon flow has altered course with no end in sight.

  17. Thanks for the tutorial! I'll have to try it out sometime!

  18. This is such a great idea to deal with that portion of the sleeve cap! I've spent so much time trying to get that curve to lay flat when folding over the seam allowance. Definitely trying this next time.

    Thanks for the tip!

  19. Hiya, is this your one and only domain or you also own others?

  20. One suggestion to avoid clipping an allowance to half the width as preparation for flat-felling:

    If you're going for a 1/4" flat felled seam, draft your pattern so you have 1/4" allowance on one piece, in this case the armhole, and a 1/2" allowance on the sleeve. When you sew the pieces together, align the 1/4" allowance with the edge of your foot, which should be 1/4" from the needle, and then align the other piece with the 1/2" marker on your sewing guide plate.

  21. I just did a boys' shirt with flat fell seams; the New Look pattern has 1/4" seams, what were they thinking? So I added 3/8" to side front and sleeve top seams and used the Margaret Islander's method mentioned above with the raw edges offset. This does not save time, believe me, because you have to measure and pin so carefully. I found that pinking the curved raw edges helped with the extra fabric enclosed in the felled seam, not to mention careful basting. Felling the long sleeve arm seam is not too bad if you go slow on basting, constantly checking underneath the foot for wandering fabric.