Rotary Cutting Instructions

Rotary Cutting

Instructions by Jan Krentz

Basic Equipment needed

  • fabric
  • rotary cutter
  • self-healing mat with ruled grid lines.  Purchase at least an 18" x 24" size to allow room for cutting.  I use a very large mat ( 60" wide) in my home studio to protect the table surface.
  • 1/8" thick plastic transparent  ruler with printed grid lines  (increments of 1/8" to 1").  Rulers are sold in a variety of sizes.  A good beginning size is 6" x 24", because you can cut across a folded piece of yardage, fold to selvedge, in one cut.

BASIC CUTTING TECHNIQUES & GUIDELINES

1.  Keep the ruler's printed lines lying directly on the fabric surface.

An optical illusion occurs when the ruler is upside down, causing an inaccurate measurement.

Consider measuring water in a transparent measuring cup. You need to be at eye level to get an accurate reading from the cup's measured marks on the side.

This is the same concept, when viewing the fabric's edge through the depth of a transparent ruler.

2.  Keep the rotary cutter's blade vertical against the edge of the ruler.

If the cutter's blade is tilted either right or left, you will get an inaccurate cut.  The width of the strip will vary, and the pieced segment will not be the correct size.

3.  Keep the ruler's guidelines aligned with the fold for straight cuts across the full width of the fabric.

Make a fresh clean up cut every 2nd or 3rd strip, as necessary to keep the edge at a perfect 90º angle to the fold.

4.  Apply small sandpaper dots to the bottom side of the ruler if you have trouble with ruler slippage while cutting.

Shifting rulers are frustrating and frequently the cause of cutting errors.

5.  For long cuts (across the full width of fabric) - develop this hand placement method:

  • Position your support hand on the first third of the ruler. Keep the hand on the outside edge, even resting your two outer fingers on the table.  This protects your hand and lessens the likelihood that the ruler will pivot.  Holding the cutter in your skilled hand, begin cutting.
  • Stop when you reach the center of the ruler, and leave your blade down in the fabric (do not lift the cutter hand).
  • Reposition your support hand to the last third of the ruler, and finish the cut.

Your support hand acts as a fulcrum point (as on a teeter totter), and the pressure of the rotary cutter's blade against the ruler's edge will cause the ruler to shift when not fully supported.

6.  Safety First!  ALWAYS close the cutter after EVERY CUT!  This is a great habit to develop.  You might accidentally cut yourself, someone else or your beautiful fabric by leaving the blade open.  Store the cutter in a closed container and location, away from curious spouses, children or pets.

Wear shoes while cutting, to protect your feet in case you drop an open rotary cutter.

Rotary cutter accidents happen quickly and unexpectedly.  The blade is extremely sharp!  Respect this tool, as you would any sharp object, such as kitchen knives, saws, scissors or razor blades.

  • Should you experience a slight nick, clean the cut, apply antibiotic ointment and an adhesive bandage.
  • For serious, deep cuts: Wrap the wound with a strip of cloth.  Apply pressure.  Ask a family member, friend or neighbor to drive you to the nearest medical facility for treatment.

To cut strips without a bend or chevron shape at the fold line:

Fold the fabric, selvedge to selvedge (as they are when rolled on the fabric bolt.) The raw edges are often uneven. (a) 

The selvedge may not match exactly.  There is no guarantee that it will be even, but your fabric should be folded so there are no wrinkles or bubbles across the surface.

 

 woven selvedges

  (a) folded edge

 

 




rotary cutter


Position the fold closest to your body.

  • If you are right-handed, the bulk of the fabric will extend to your right.
  • if you are left-handed, the fabric extends to your left.

Align the FABRIC FOLD with a cross line on your rotary ruler to insure accurate cutting.

 

Make a clean up cut, which will remove the rough raw edges from one side of the fabric.

  • Right handed: the cut will be on the left edge of your fabric. The bulk of the fabric will extend out to your right.
  • Left handed: the cut will be on the right edge of your fabric. The bulk of the fabric will extend out to your left.

Tip:  Lay a ruler on the cutting mat before you purchase it and make sure the grid has been stamped on accurately.  The lines of the mat should disappear under the lines of the ruler.  Don't buy it unless it is.  Now, knowing it is accurate, you can make sure your ruler is at right angles to the fold for every cut by being sure the mat lines disappear under the ruler lines!

CUTTING THE STRIPS

Determine the required strip width.

Align the correct ruler mark on the freshly cut edge of the fabric.

The fold should still match a ruler cross line EXACTLY, insuring a straight strip.

This illustration shows how to cut a 2" strip, measuring from the freshly cut edge.

YOU will cut the strip width required by your pattern.

Tip:  When you are cutting strips longer than 6", use a square ruler laid on the selvedge and butted against your long ruler to make sure the long ruler is at a right angle.  If you put that ruler on the outside edge (by the clean cut), it can also help extend the width of your cutting ruler for wide cuts.

 

Additional Hints for Rotary Cutting by Carol Miller

When you look at cutting directions (or are writing your own), it is handy to know how many strips will give you the required number of pieces.

Simple shapes are not hard to figure out.  Most American fabric has 40 usable inches.  This takes into account the shrinkage and the slight differences in width between fabrics.  If you need to cut 4" squares, you will get 10 from each strip.  If your pieces are 3.5", simply divide that number into 40.  You will get 11 and a long repeating fraction.  Ignore the fraction.  You can get 11 of the 3.5" units from one strip.

Suppose you need two related sizes, like 3.5" and 4.5" and after figuring out the whole strip amounts, you find you need four more of each shape?  You could cut two strips, one at each width and have the remaining amount leftover.  On the other hand, you could cut ONE strip at the wider width, cut the number of patches you need and then cut out the smaller shapes from the remainder, trimming off the excess width.