A QuiltPlan piecing reference
Before You Sew
accurate cutting and the scant ¼″ seam: the two skills every block depends on
Every cutting number in every other QuiltPlan reference assumes two things: your fabric is cut square and to size, and your seam is a scant ¼″, not a true one. Get these two habits right once, and every block you piece afterward comes out the size it is supposed to.
Self-healing cutting mat
Clear acrylic ruler with printed grid lines
Rotary cutter, fresh blade
¼″ presser foot (or a marked seam guide)
Cut your square ½″ larger than the finished size: a ¼″ seam allowance on all four sides.
Square up one edge first
Fold and press the fabric, lay the ruler's grid line on the fold, and trim the ragged raw edge away. This is your reference edge for every cut that follows.
Measure from that edge, then cut
Line up the ruler's own grid line to your measurement, not the fabric's raw edge. Hold the ruler firm, keep the blade against the ruler the whole cut, and cut away from your body.
Sew a hair narrower than ¼″, on purpose
A scant ¼″ seam sits one or two threads inside the true ¼″ line. It looks like a rounding error; it is not one — it is what makes the numbers on every other sheet come out right after pressing.
Test it before you trust it
Sew three 1½″ × 3″ strips together along the long edges. Press the seams, then measure straight across. A true scant ¼″ seam measures exactly 3½″ — if it does not, adjust your seam guide and test again.
| Finished square | Cut size |
|---|---|
| 2″ | 2½″ |
| 3″ | 3½″ |
| 4″ | 4½″ |
| 5″ | 5½″ |
| 6″ | 6½″ |
The mistake almost everyone makes once
Sewing a true ¼″ instead of a scant one. It looks correct at the seam, but every piece comes out just slightly small — and that small shortfall compounds across a whole block, then a whole quilt. If your finished blocks keep measuring a little undersized, this is almost always why.
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