Question

Explain the steps involved in the preparation of a bias strip.

Hint:

Always join bias strips using a diagonal seam. A straight seam would concentrate all the fabric bulk in one spot when folded, creating a lump in your binding and making it difficult to sew smoothly.

Answer 1

Step 1: Understanding Fabric Grain and True Bias Geometry:
Woven fabrics are composed of warp threads (lengthwise grain) and weft threads (crosswise grain) intersecting at a $90^\circ$ angle. These straight grainlines have almost no stretch. True Bias is the diagonal line running at a precise $45^\circ$ angle to the warp and weft. Cutting fabric on the true bias unlocks maximum mechanical stretch, elasticity, and flexibility, making bias strips ideal for clean-finishing curved edges (like necklines and armholes).

Step 2: Folding the Fabric to Find True Bias:
Lay the woven fabric completely flat on a cutting table. Take the cut crosswise edge (weft) and fold it over to align parallel with the lengthwise selvage edge (warp). This fold forms a perfect right-angled triangle. The resulting diagonal fold line lies at precisely $45^\circ$, representing the true bias. Lightly press this fold with an iron to mark the baseline.

Step 3: Marking and Cutting Parallel Strips:
Unfold the fabric fold. Using a transparent grid ruler and tailor's chalk, draw parallel lines from the pressed $45^\circ$ baseline at your desired strip width (typically $1''$ to $1.5''$ depending on the project). Using sharp fabric shears, cut carefully along these marked lines to produce individual bias strips.

Step 4: Joining Bias Strips with diagonal Seams:
To join the short strips into a single, continuous binding strip, use diagonal seams rather than straight seams:

• Trim the ends of each strip to a clean $45^\circ$ angle.
• Place two strip ends right sides facing at a $90^\circ$ angle, overlapping the tips slightly by $\frac{1}{4}''$ so the seam lines align perfectly.
• Stitch across the intersection with a standard $\frac{1}{4}''$ seam allowance.
• Press the seam allowances open, and trim away the small protruding triangular tips (“dog ears”).