Description Simply align the 90 degree edge of the ruler with the selvedge, trace and, voila! you have a 45 degree line to trace, to start creating your own bias binding tape from beautiful scrap fabrics, as well as in self fabric. Then use the grading line increments to trace a new line off the original, 2.5cm away. Make as many lines as you need to achieve the (overall joined) quantity/length required.