This technique works just as well for non-foundation pieced blocks where you have to intersect many seams and want to keep your points sharp and not have a hard lump where they meet.
Piece the components of your block as usual. In the case of this compass block, it consists of eight wedges that will be joined to form a complete circle. I will be piecing them together in pairs, then fours, then all together.
2. reduce the seam length on your sewing machine if you are foundation piecing. Leave it alone for regular piecing.
place the matched unit under the foot and lower the needle so that it pierces the fabrics at the start of the sewing line, not the edge of the piece. For non-foundation pieced units, start your seam a quarter inch from the edge, as you would for setting in a seam or mitering a corner. see below.
|sewn seam starting 1/4" from edge|
|press seam open, keeping points at corner aligned|
4. repeat the steps above for all the components of the block, resulting in four pairs of pieced units:
6. place the unit under the needle and presser foot and lower the needle so that it pierces the fabrics at the point where the seams intersect (1/4" from edge of fabric, see above). Sew the seam, remove paper under the seam allowance, and press open.
Your unit should look similar to that below. There should be a 1/4" cleft where the seams meet and the fabrics are not sewn together. repeat to sew the other half of the block.
Begin sewing at one edge of the block as usual, sew across the center seams, closing the cleft that was previously left unsewn. see below:
8. press the seam open ...