A bias is a diagonal cut. To cut a true bias, fold over the corner of the cloth so that the warp and woof threads are parallel. A choice bias is a true bias, having the twill of the cloth at right angles to the cut. Great care should be taken in measuring and cutting bias strips to have them the same width throughout the length. Also avoid stretching after cutting.
a. To cut a bias facing, bias binding or fold, measure in the desired width on the true bias at a number of points. Draw a line, crease in a fold or baste where the facing is to be cut off.
b. To put on a bias facing, place the edge of the strip, right sides together, even with the edge of the cloth to be faced, baste and stitch. Turn the facing back exactly in the seam and baste along the edge so that the facing will not show on the right side. Turn the fold at the top, baste and hem. This process may be reversed for a right-side facing.
A bias facing for a curve should be cut narrow enough so that by stretching one edge of the facing it will lie perfectly smooth when finished.
c. To join two bias strips - Cut the ends to be joined straight with the threads of the cloth and place the right sides together, slipping the top piece past the under piece the width of a seam, but having the top edges even. Stitch where the facings cross, open the seam and crease; or, after trimming, a seam may be turned back at the end of each piece and the folded edges over-handed together.