This tutorial will show you how to sew curves that are concave, convex as well as sewing curves that are opposing. Even beginners can get great looking curves with a little practice and these few simple tips.
Sewing Curves - Convex
A convex curve is simply a curve that faces outwards much like a circle. It can be commonly found on pocket edges, clutches and bag flaps.
Step 1 - Mark Seam
Draw the seam allowance line using a removable pen or tailor's chalk. This gives you something to follow when sewing and will increase your accuracy. Without a line to follow it can be hard to visualize the curved seam line and predict when to turn.
The easiest way is to mark from the edge with a seam gauge or ruler in little dashes and then join them up.
Step 2: Place your pins vertically so that you can Follow the curves with minimum interference. Place the heads on the outside of the curve so they are easy to remove as you go along.
Further reading: how to pin seams
Step 2 - Sewing Curves
The best way how to sew curves is to set your machine to a smaller stitch length. Try a length of 2.0-2.5. Stitch slowly and gently guide the fabric with your fingertips.
Keep your eyes on the marked seam line in the front.
For gentle sewing curves, you should be able to stitch in one motion without stopping.
For tight curves, you may need to stop with the needle down in the fabric, lift the presser foot, pivot the fabric and start stitching again. Make multiple small adjustments rather than one large adjustment to maintain a smooth curve. This will also stop the fabric from wrinkling up and catching on your presser foot.
If the curve is really tricky you could sew the hardest part by turning the hand wheel for maximum control.
Step 3 - Clipping
Once you have sewn your corners you will need to remove some of the excess fabric in order to maintain the smoothness of the curve when turned the right way out. For convex curves cut triangular notches out of the seam allowance.
Step 4 - Turn & Press
Turn the right way out and give your curves a good press.
Sewing Curves - Concave
A concave curve faces inwards and can be commonly found on necklines and armholes of garments. Here you can see a curved neckline with facing.
You will sew it the same way as a convex curve with the only difference being the way you clip the seam allowance. Instead of clipping notches, you can just make little snips ending just before your stitching line.
Give it a good press and here is how it looks.
How to Sew Curves - Opposing
So what do we do when we have 2 curves facing in opposite directions? You will often see this on quilting patterns or in garments with color-blocked segments. You will also use this technique when joining sleeves to armholes.
Step 1 - Add Seam Allowance
If your pattern doesn't already have a seam allowance added then now is the time to add it. If you add smaller ¼ inch (6mm) seams it makes it easier to fit the curves together.
Step 2 - Mark Centers
Mark the center of the pieces and pin them right sides together. See how the rest of the curves are now facing opposite directions?
Step 3 - Ease and Pin
Match and pin the ends of your pieces and then work the in-between sections together. Place your pins vertically to hold the fabric in place and out of the way. The greater the curve, the more pins you will need.
Step 4 - Sewing Curves
Now stitch along the seam with your seam allowance. It is easier to stitch from the top curved piece. Run your finger underneath regularly as you sew to make sure nothing is caught up underneath.
Step 5 - Clipping
Clip the seam allowance to release tension.
Step 6 - Press
Open up your piece and give it a good press. This will make all the difference to sewing curves.
The seam allowances should both be pressed to the one side. It will naturally go in one direction. Don't try and press the seam allowances open as it is generally too difficult.
And there you have a nice color-blocked piece.
Now you know how to sew curves you could actually make more curved pieces and turn it into a quilt!