Cutting pattern pieces on the grain line for woven fabrics is the most important step in the sewing process.
New sewers may not know what that means or why it’s so important. Quite simply, if your pattern pieces are not cut on the grain line, the finished garment will twist and drape sloppily.
The main reason fabric is off grain is how it’s rolled onto a bolt. As the roll gets bigger the upper layer of fabric will tend to shift out of line. Fabrics of a lesser quality also tend to be off grain.
There are two grain lines on your fabric. The weft (the cross grain) and the warp (the length grain). The warp grain is parallel to your selvages and the weft runs across perpendicular to the selvages. The bias on your fabric runs at a 45 degree angle to these grainlines. The warp thread is generally stronger and is least likely to stretch out of shape.
The warp grain or selvage side does not need to be straightened – only the weft or cross grain.
From my experience, the best method to straighten the cross grain is by pulling a thread.
Now your fabric is ready for the next most important step.
Step 2: Pre-Wash | Pre-Shrink Your Fabric