Machine Quilting Practice #2: Clamshells

Last week, we started our summer machine quilting practice sessions with a straight line grid. You were able to practice machine quilting with a walking foot, beginning and ending your line of stitching with tiny securing stitches, and jumping over a section to resume quilting on the other side. How did it go? This week, we move on to free motion quilting beginning with the classic clamshell design.

For an individual practice sandwich, you will need an 8″ square of fabric for the top and a slightly larger square of batting and backing fabric. Mark the Clamshells on the 8″ square of fabric, layer and baste.

For a nine-block sampler quilt, you will need a 20″ square of fabric for the top and a 22″-24″ square of batting and backing fabric. Please read the Instructions for Preparing a Machine Quilting Sampler for more information about marking the quilt top.

Set up your machine for free motion stitching by lowering (or covering) the  feed dogs and installing a darning or free motion presser foot. You can usually identify the free motion foot by the spring in the shaft. The foot itself comes in a variety of shapes including a closed circle, open circle, and oval. When the needle is down, the spring compresses the quilt to take the stitch; when the needle is up, the spring releases to allow the quilt to be moved for the next stitch.

Begin the clamshell design at one end of a row of half-circles. Pull up the bobbin thread as described in Beginning and Ending Machine Quilted Stitches and take the first small stitches by moving the quilt slowly under the needle. Continue moving the quilt under the needle, following the marked clamshells. You can work horizontally along the row from left to right (or right to left)…

… or vertically from top to bottom (or bottom to top).

The goal is to keep the quilt in the same orientation for the entire row. While you may be able to turn this practice quilt sandwich, remember that larger quilts cannot be easily turned. Practice stitching right and left, up and down. This is the beauty of sewing free motion! Secure the end of the row with small stitches and clip the threads.

The second row begins and ends with a quarter-circle. When you get to the end of the row, you can continue stitching the third row by reversing the stitching direction (not turning the quilt, remember!). Again, you can work horizontally…

… or vertically.

Continue in this manner until the square is filled with clamshells. Try to keep your stitches equal in length as you are quilting. When sewing free motion, the stitch length setting on the sewing machine is irrelevant. You create the stitch length by moving the quilt under the needle. Don’t get discouraged – this will take practice! It is, after all, a practice piece, so don’t be too hard on yourself. You will improve if you keep at it. And we’ve got a whole summer of practice sessions ahead. Next week, it’s the orange peel design.

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  1. Hi Sandra,
    Marking quilting designs for machine quilting is a big subject. Designs can be traced or marked from the top with templates or transfer papers. You might find the following blog posts helpful:

    Hope this gives you some ideas!
    All the best,

  2. Sandra Clarke says:


    I am wanting to do some clamshell quilting to some blocks and found your blog while looking. How do I transfer the design onto the blocks? There is no way that I could just free motion the shapes, they would not be at all even. I have printed your pattern sheet and resized it but now do not know what to do. Any help would be appreciated.


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