The best development in tools for quilters, unquestionably, is the rotary cutter. You can cut quilt pieces in a fraction of the time it would take using scissors. The key to accurate cutting is to square up your fabric before you open your cutter. If you skipped Working with Fabric, please read it now so you will understand the importance of aligning fabric grain before continuing.
Once you become proficient at rotary cutting, you will be able to quickly produce stacks of precision-cut pieces at once so you can start sewing. Precision cuts equal precision seams, yielding perfectly aligned pieces and clean points.
Position fabric for cutting
Before you cut, be sure you are cutting with the grain of the fabric. One or more straight sides of your piece should follow the fabric's straight grain. It is vitally important that the first cut be straight, as all succeeding cuts will be made along the line of the first.
Place fabric on cutting mat with fold toward you and selvage edges at top. Fold the fabric in half lengthwise, bringing the fold edge up to the selvage edge. Be sure that the crosswise grain of the fabric is aligned. Align the straight edges of the fabric to the grid on your cutting mat to be sure edges are straight.
Square up the fabric:
Align the grid on the ruler with the folded edge of the fabric to insure a perfect
90° angle to the cutting edge. This should coincide with the crosswise grain,
if not adjust your fabric.
Righties will have the bulk of the fabric to their left and will cut off approx
1" from the right edge.
Lefties will have the bulk of the fabric to their right and will cut off approx
1" from the left edge.
Cutting Fabric
Instructions below are numbered "R" for righties and "L" for lefties
1R: Hold the ruler firmly in place with your left hand, spreading your fingers apart and keeping them away from the right hand edge of your ruler. You little finger should rest on the fabric, this helps to keep the ruler from sliding. Apply pressure onto the ruler with your fingertips and heel of your hand. With the rotary cutter blade against the right side of the ruler, roll the blade along the edge with just enough pressure to cut through fabric layers. You now have a straight edge to guide your next series of cuts.
1L: Same as above, but hold the ruler with your right hand and keep fingers away from left edge of the ruler. Roll the blade along the left edge of the ruler.
2R: Rotate your cutting mat with the fabric still in place. Align the ruler to the left of the cut edge, measure the width of your strip and cut as many strips as are required for your pattern.
2L: Same as above, align ruler to right of the cut edge.
Open every third strip to be sure you are still cutting straight. If you open a strip and notice a curve or swerve at the fold lines, your must start from the beginning and square up again.