Sewing Curves Successfully – Joining Rounded Shapes

Sewing curves

Sewing curves successfully is a matter of patience and skill.  Joining rounded shapes with accuracy will allow you to end up with an elegant and attractive curve.

No matter what material you are using, this easy tutorial will help you sew any size of rounded shape. Some examples include; curves on rounded bags, bag or backpack bottoms, pockets, collars, and hats.

For this sewing tutorial, I am going to be using a test bag.  I am making a new bag pattern and this is going to be my prototype for the pattern, to make sure it works and all pieces fit well.

The bottom will have a rounded, but elongated shape.

Sewing curves

These tips will work with making a complete circle as well.  This tutorial is intended for beginners and those of you who have a hard time sewing curves.

Instructions for Sewing Curves Successfully

Place the piece with the straight edge print side up.

Sewing curves

Fold the piece in half and mark the middle with a fabric marker.

Sewing curves

Do the same with the rounded piece.  Fold one way and then the other to make four marks on the top, bottom, left, and right.

Sewing curves

Using a ruler, make marks at the same distance from each other.  That way the marks will match no matter where you start sewing.

Sewing curves

Place the piece with the straight edge print side up.  Place the rounded piece print side down on top matching the center marks.

Sewing curves

Walk the rounded piece 3/8″ at a time.

Sewing curves

Make marks both on the straight edge piece and the curved piece until you reach the seam-allowance.

Sewing curves

Your pattern will tell you what is the seam allowance.  In my case, it is 3/8″ (1cm).  If I was sewing curves within a circle, I might even make closer marks to avoid loosening the seam of the circle.  You can really see the bad effects of not doing this on cheaply made bags.

Sewing curves

Sewing curves

Sewing curves

Sewing curves

What you are looking for is a smooth curve.

Sewing curves

Sewing curves

There are two ways to make the seam allowance lay flat and to make the curve smoother.   You can clip the seam allowance making notches 3/8″ at a time or just reduce the seam allowance by cutting 1/8″ off.

Sewing curves

Now it's your turn to practice sewing curves

This is a valuable skill that's worth mastering.

You can try the Roundabout bag or the Bucket bag or you can wait for me to finish this bag to share it with you on Sunday.

Until next time and Happy Sewing!


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10 Responses to Sewing Curves Successfully – Joining Rounded Shapes

  1. Vicki Gustafson says:

    Thank you for the instructions. Part of this was very vague. After marking all the quarter placements, at what specific increment do you place the remaining marks between the 1/4 marks?

  2. Beal says:

    Very helpful – thank you!

  3. Kimberly Ho says:

    Do you have a video showing the steps as well?? I think I understand the process, but to see it live vs pictures would be helpful.

  4. Mary says:

    There is such a simple way of sewing curves, run a gather thread just in the seam allowance and again 5mm away also in the seam allowance. Mark eighths. This does 3 things, it gives a guide line to finally sew on which is useful if piping seam, it controls the bias and also the seam allowance. Sew perfect first time. Yes it might not work on stiff vinyl but it does on soft leather and a treat on velvet. Same trick for gathered sleeve heads.

  5. Wendy says:

    Are you sewing the flat piece to the round piece and then sewing up the sides of the flat piece afterwards? I’ve always been told to sew the side seam first, but your method seems a lot easier if I understand it correctly.

    • Debra says:

      This confused me at first as well. But if I’m following the blog correctly, this is just a breakout tutorial from the Reversible Tote bag on the blog. I think the markings are made when everything is flat, then the sides are sewn before pinning the bottom to the body. HTH

  6. Yasmin says:

    Surely if I place the pieces both print side up, it will come out wrong? Shouldn’t the right sides be together when I go to sew?

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