What You Need to Know about Grain Lines and Squaring Up

Have you ever viewed a quilt which looked like this?

It’s a really nice quilt, and the maker may have spent a lot of time thinking about design and color and techniques.  But there’s just something off about the quilt.  You may not be able to put your finger on exactly what it is, but something is off.  So, you wonder is it you, or is it something else?

Well, if you looked at the quilt above and thought those thoughts, it’s not you.   It’s the quilt.  Even though a quilt may be perfectly pieced or appliqued beautifully, there’s still something wrong.  It doesn’t hang straight.  It may look a bit wavy.  It simply doesn’t look right, but you can’t figure out exactly what’s wrong with it.  There are technically a couple of things which could be happening here, either independently or in conjunction with each other – off grainlines and/or poor squaring up.

As I’ve stated many times before, fabric has three grainlines:  crosswise (also known as width of fabric or WOF), length wise (known as length of fabric or LOF), and bias – which cuts across both the crosswise and length wise grains.  For my quilters out there who are also garment makers, you are probably familiar with these terms.  Generally, if quilters are cutting fabrics in strips in preparation to sub-cut it into units, the strip is cut across the width of the fabric.  And here is where the first issue may crop up.

Quilter’s cottons (or any other 100 percent cotton fabric for that matter) are woven.  This means the threads or yarns are placed perpendicular to each other and are attached by weaving, to make up the warp and weft of the fabric.  Once the fabric is completely woven, it’s processed, finished, folded, and wrapped around a bolt.  During these processes, the threads can shift, causing it to lose its perpendicularity. 

Now the fabric is off grain.  And to be honest, most fabric is off grain by the time it’s rolled off the bolt to be cut.  If you’re making a garment, cutting fabric strips to be sub-cut, or cutting out large quilt blocks as either setting blocks or applique backgrounds, it’s important to put the fabric back on-grain.  This is not a difficult process at all.  Simply make a small cut across the selvedge, about an inch in from the side:

And rip the fabric from selvedge to selvedge. 

Then re-fold the fabric to make your crosswise (WOF) cuts, making sure to line up the torn edges.  Now you’re ready to rock and roll.

At this point, let me throw in a Zone of Truth.  If you’re cutting small fabric pieces to go into block units, it honestly doesn’t matter if the fabric is on-grain or not.  By the time you get those pieced and quilted, no one should be able to tell if you’ve corrected the grain line or not.  However, the larger the fabric pieces, the easier to tell if they’re off-grain.  Even when they’re quilted, they will want to ripple and not lie flat.  My general rule of thumb is if I am cutting strips or blocks 3-inches or larger, I make sure my fabric is put on-grain. 

Now let’s talk about what may be the second issue which could be wrong with the quilt at the top of this blog:  Improper or absent square-up.  What is square-up? In broad terms, squaring up a quilt pertains to the quilt sandwich – it’s a step taken after the quilt is quilted and before the binding is sewn on.  The process makes sure the four corners are at a perfect 90-degree angles.  However, like I said, this is a broad definition.  Personally, I think a quilt should be squared up at every step during construction.  Let me explain.

To me, squaring up a quilt begins as soon as you have the quilt pattern in hand.  The very first thing I encourage any quilter at any level to do is read the pattern twice before purchasing fabric or making the first cut.  The first read-through is to get you acquainted with the process the designer took.  And now here’s a Zone of Truth about fabric designers:  Some of them are really great.  Some of them are not.  Don’t be fooled by a pretty cover.  Take that pattern out and read it.  As you read it, look for certain aspects:

  1.  Pictures, illustrations, or line drawings – Quilting is a visual art.  Sometimes a picture can be far more helpful than words.
  2. The cover picture is clear – While I may not choose the color way the designer chose, the cover picture has enough clarity I can take a picture of it with my cell phone and flip it to black and white so I can see how many lights, mediums, and darks I need.
  3. It indicates in some way if it’s a beginners, intermediate, or advanced quilting pattern.
  4. If it’s an applique pattern, it tells you if the applique pattern pieces are reversed or you need to reverse them with a light box.
  5. The designer has listed his or her website.  This is important.  Go to the website and see if the designer has updated the pattern.  No matter how hard designers try (and the vast majority of them try really hard) not to make mistakes, mistakes do happen.  Good pattern designers usually have a place on their website where they list the pattern, any mistakes, and the corrections.  If you cannot find a corrections tab on the designer’s website, Google the pattern.  If nothing about the pattern is returned but the images of the designer’s quilt and their site, you may want to rethink making the quilt.  This usually means either no one has purchased it, or the directions are so poor no one has attempted it. 
  6. The directions allow for a bit of extra fabric in case you make a cutting error.
  7. As you are constructing your block units, the pattern supplies you with an unfinished unit measurement.

For me – and I’ve quilted for 35-years at this point – these seven aspects are important.  However, number 7 is super important in the squaring up process.  Let’s say you have to join a half-square triangle to a square.  The HST has an unfinished measurement of 2 ½ inches and the square also has an unfinished measurement of 2 ½-inches.  If the pattern lists this unfinished block unit measurements as 2 ½-inches x 4 ½-inches, you realize once you’ve sewn the HST and square together, the unit should measure 2 ½-inches x 4 ½-inches.  Once the HST and square are joined and pressed, you can measure it.  If it is the correct measurement, you can proceed to join all of these units together, checking as you go to make sure the unfinished measurements stay consistent.

However, if the joined HST and square aren’t 2 ½-inches x 4 ½-inches, you realize you must take steps to correct it.  Seam allowances can be examined to see if they are a true ¼-inch.  You can re-measure the HST and square to make sure they have been cut and trimmed correctly.  In other words, you can correct the tiny mistakes before they become huge quilty issues.  This is why those unfinished block unit measurements are so important. 

But what if the unfinished block unit measurements aren’t in your pattern?  Don’t worry.  You can figure out those measurements on your own.  For instance, let’s take a look at this block:

This is the Greek Square block, and it’s made up of HSTs and squares which are pieced from two rectangles.  The finished block is 6-inches, which means each HST and pieced square should finish at 2-inches (2 + 2 + 2 = 6).  Unfinished means you simply add ½-inch for the seam allowances.  So as you’re piecing each HST and square, you want those to be 2 ½-inches, unfinished.  Once they’re joined together in rows, the row should come out to 6 ½-inches (2 ½ + 2 ½ + 2 ½ = 7 ½.  Then subtract two ½-seam allowances for the middle block:  7 ½ – 1 = 6 ½.  Once the square is set into rows, that extra ½-inch seam allowance will go away and the block will finish at 6-inches). 

Figuring out the unfinished measurements isn’t hard, and it’s important to do if the pattern doesn’t supply them.  While all of this may seem like intense (and even unnecessary) attention to detail, it’s these actions which are the first “squaring up” of the quilt.  You make sure the block units are the correct size.  If they’re not, you adjust cutting, seam allowance, or even the thread (by switching to a different weight or ply) to make sure the units come out at the correct unfinished size.

Once the units are made, join them together to make the block.  Because of all the care put into the units, the block should come out at its correct unfinished size.  However, it’s still necessary to measure the blocks to be sure.  I make several blocks and then spend some quality time at my cutting mat, measuring and trimming (if needed).  This is the second “squaring up.”

Now let’s talk sashing.  Sashing is the strips of fabric you put between the blocks and between the rows.  It has lots of design possibilities.  Sashing can be pieced or appliqued.  Wide sashing opens up lots of quilting opportunities.  It adds width and length to a quilt.  However, if used correctly, sashing can also be a great squaring up tool.  I learned this little trick when constructing my Dear Jane.  As you’re cutting your quilt out, also cut the vertical sashing to the size required by the quilt pattern.  After you’ve constructed your block, sew a sashing piece to the right side of the block.  If the sashing and the block are the same size – whoop whoop!  Your block is squared up, and the sashing is the right size.  If one is off, re-measure both and make corrections where needed.  This is a great, little square up trick, and it saves time.  Once all your blocks are completed, the sashing is already sewn on and you’re ready to sew the blocks into rows.

Speaking of rows, now it’s time to sew the sashing between the rows and on the top and bottom of the quilt (if required).  It’s important to make sure all the rows are the same length.  There’s a couple of ways to do this.  If the pattern doesn’t have any borders, you can check and see what the finished width of the quilt is and add ½-inch.  If your rows measure this, you’re golden.  If the pattern has borders, you can subtract the combined border finished width from the width of the finished quilt and add ½ inch.  All the rows should come pretty close to this width.  If you’re off a smidge (1/4-inch or less), don’t sweat it.  This amount can be worked around. 

Once you’re sure your rows are approximately the same length, now it’s time to make your horizontal sashing to go between the rows.  If it’s a solid piece of fabric, cut the  fabric strip across the WOF (joining pieces if necessary) to fit the measurement of the row width.  Find the center of the row of blocks and the center of the horizontal sashing and pin the two centers together.  Then pin out from the center for the left and right sides.  If you’ve measured, cut, and joined correctly (if needed), the horizontal sashing should be easy to pin into place. 

Sometimes the sashing looks like this:

Those small squares which fall beneath the sashing are called cornerstones.  And while this may look a tad intimidating to construct, it’s really not.  Here’s how it goes:

  1.  Cut the strips of horizontal sashing the finished width of the block, plus ½-inch for the seam allowances.  So, if the finished width of your block is 8-inches, you’d cut the strips at 8 ½-inches.
  2. Cut the cornerstones the same size as the finished width of the vertical sashing, plus ½-inch.
  3. Sew the cornerstones to the horizontal sashing strips. 
  4. Sew the horizontal sashing to the rows, matching and nesting the cornerstone seams with the vertical sashing. 

If block units, blocks, and all the sashing were squared up, once the quilt center is assembled, it should automatically be squared-up, too, right?  Is there a need for additional squaring up at this point?

Tune in next week to find out the answer to this and other burning quilty questions….

Until Next Week, Make Your Quilt Yours!

Love and Stitches,


4 replies on “What You Need to Know about Grain Lines and Squaring Up”

Good reminder, and thank you, but what about all the prints that are not printed straight? Can the factories adjust their machines better? It is frustrating and expensive to order pretty fabric, and strive for precision piecing, and then have the eye follow the line as it disappears into the seam allowance.

I completely agree! This is one of my pet peeves concerning fabric. Unfortunately, other than writing strongly worded emails to the fabric manufacturers about the quality of their goods, there’s not a whole lot we can do. I can tell you how I handle the situation. If I have fabric which isn’t printed straight, I cut by the print — I don’t deal with the grain lines. However, I would only use that fabric in small units and patches — nothing over four inches. Any larger than that and the block may come out wonky and with enough wonkly blocks, you can throw the entire quilt off.

Thanks so much for taking the time to read and comment.


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