It never ends. For quilters, that perfect set of piecing techniques which allows us to make perfect points and matching seams is a work in progress, no matter what our skill level. As we tackle projects of increasing difficulty, we hone our piecing skills by adding new techniques, methods and tools, zeroing in on our weak areas and expanding our piecing repertoire. In this tutorial, I am sharing my tips for perfect quilt piecing that support our efforts for achieving perfect piecing. Rather than focusing only on the ¼ inch seam, I am also including information on machine accessories, the usage of leaders and enders, starching and stretching, perfect pressing and pinning and gluing. All of these areas are integral to the piecing process. They provide a good foundation from which to create our own unique “perfect set of piecing techniques” toward our end goal of perfect piecing.
The Perfect Quarter Inch Seam
The method to achieve the perfect quarter inch seam is unique to each sewing machine and even to each presser foot. This is why its best (for those with multiple machines) to use the same machine for an entire piecing project as even a slight variation can cause problems. As every quilter knows, piecing accuracy is paramount! Even a variance of one or two threads can make a huge difference across a block with multiple seams. The quarter inch seam is probably the most focused on and important of all the tips for perfect quilt piecing, so we will go into some depth here.
Why a Scant Quarter Inch Seam?
Many patterns call for a scant quarter inch seam. I use the scant seam probably 95% of the time. The reason for this is that quilt designs assume that when the sewing and pressing is done, only ¼ inch of fabric is removed from the front of the block. Because of thread and fabric thickness, the seam allowance needs to measure slightly less than a quarter inch for the finished size to be accurate….thus, we use a scant quarter inch seam.
Measuring a Quarter Inch Seam on your Machine
Before you can mark your machine bed and decide on which type of sewing guide your prefer, you need to find the “sweet spot” for your machine. One method of doing this is with a seam gauge, such as the Ideal Seam Gauge shown below.
This gauge has markings for 1/8 inch through 1 1/2 inches, including the ¼ inch and scant ¼ inch widths. You position the gauge under your presser foot and drop the needle through the hole of your desired seam width. This gives you the exact spot on your machine bed you need to mark with your sewing guide.
Presser Feet for Piecing
There are many presser feet on the market that provide a way to measure a quarter in seam as well. The edge of the foot is often used as a gauge, such as the Husqvarna-Viking presser foot shown on the left below. Some feet have a built-in sewing edge, such as the Bernina presser foot shown below on the right. Many sewing machine manufacturers have their own patchwork foot specific to their machines. There are also generic feet available.
Using the presser foot as a guide on its own can create a problem if it measures as a full ¼ inch, rather than a scant ¼ inch. This usually requires you to find a spot on the foot that is slightly less than the edge and try to keep the fabric secure along this line as you sew. Another option is to move your needle one or two notches to the right, thus narrowing the seam. This won’t work however, if you are using a straight stitch machine or a straight stitch needle plate (more on this below).
Straight Stitch Needle Plate vs Zig Zag Needle Plate
Using a straight stitch needle plate (instead of a zig zag needle plate) is one of the best ways to improve the quality of your piecing. Some machines come with a straight stitch plate while some manufacturers require you to purchase this separately. Below are examples of straight stitch (left) and zig zag (right) needle plates.
The straight stitch needle plate prevents the leading edge of your piecing from being pushed down into the bobbin area. When working with small fabric pieces or sewing diagonally from corner to corner, this becomes imperative.
Guiding Your Fabric
While some people prefer to use only the edge of the presser foot as a guide for their fabric as they sew, others prefer to mark the bed of the machine and align their fabric to this marker as they sew. I fall into the latter category. After having tried many things, including painters’ tape, a stack of sticky notes and magnetic seam guides that affix to the bed of the machine, I have been most happy with a product called Sewing Edge from C & T Publishing. These are reusable vinyl strips that you affix to your machine bed and use as a guide for the fabric to follow as you sew. They provide a "ledge" you can hold your fabric against as you sew. I really like these strips because they are repositionable and re-usable and they don’t leave any sticky residue on your machine. Below is a photo of the Sewing Edge in use on my Juki TL-2010Q.
My Bernina 770 (which is a 9mm stitch width machine) has a screw-in type of guide that is adjustable to any width:
I have used many different machines over the years, both 9mm and 5.5mm, both zig zag and straight stitch. In my experience, the 5.5mm machines are better for piecing as the narrow feed dogs hold the fabric tighter. On my Bernina, when using the patchwork presser foot to achieve the 1/4 inch seam, the fabric does not cover the feed dogs completely, which allows the fabric to move slightly. For me, its harder to achieve a perfect 1/4 inch seam on a 9mm machine. This is especially true when piecing small or intricate blocks. My favorite all-time machine for piecing is my straight stitch Juki TL-2010.
Testing Your Quarter Inch Seam
After you get your seam width measured and have decided on a method of guiding your fabric, its time to test your seam width for accuracy. You can do this by sewing three fabric strips together. Cut three strips, each measuring 1 1/2 inches wide by 3 or 4 inches long.
Sew them together, side by side, then press open. The center strip should measure exactly 1 inch in width.
Leaders and Enders
While we are still on the subject of actual piecing at the sewing machine, let's talk about leaders and enders. These are scraps of fabric that you sew off of and onto at the beginning and ending of your piecing. They serve three purposes:
- They allow you to stitch on the very edge of your fabric (both when you begin stitching and when you end). This is important because you don't want the edge of your stitching to unravel while you are trying to match those seams.
- They allow you to keep your stitching line perfectly straight without any veering, both at the beginning of your seam and at the end.)
- They keep any birds nests or thread build up from happening at the beginning of your seam.
To use leaders, you simply place a piece of scrap fabric under your needle and begin sewing. When you are nearing the edge of the leader fabric, place your fabric piecing right up next to the leader and stitch onto it.
To use enders, you place another fabric scrap up next to your fabric piecing as you near the edge and stitch onto it.
You can choose to use both leaders and enders, or just leaders. I prefer to just use leaders. They can be used for individual piecing or at the beginning and end of chain piecing as well.
Starching and Stretching
I had been quilting for several years before I discovered just how much the use of starch could help my piecing success. Before we get into the specifics of starching, let's visit the topic of fabric grain and how it relates to stretching and distortion as we sew.
The grainline of fabric refers to the direction of the warp and weft threads used in weaving the fabric. There are three grainlines - Straight or lengthwise grain, cross grain and bias grain as described below.
- Straight or Lengthwise grain runs the direction of the warp threads which run parallel to the selvages. When we cut fabric parallel to the selvage edge, we are cutting on the straight grain. Fabric cut on the straight grain fabric has the least amount of stretching, nearly no stretch at all.
- Cross grain are the direction of the weft threads that run perpendicular to the selvages. When we cut along the width of fabric (perpendicular to the selvage edge), we are cutting on the cross grain. Cross grain has the next amount of stretch, much more than the straight of grain.
- Bias grain is when fabric is cut at a 45 degree angle from the straight of grain. Bias grain has the most amount of stretch. This is why we need to take extra care when working with triangles or fabric cut on the diagonal. Bias grain is often used when stretch is needed, such as when you need binding for a round or curved shape.
How to Determine Straight Grain from Cross Grain?
If your fabric is already cut and you can no longer see the selvages, how do you determine which is the cross grain and which is the straight grain? The easiest way for me is the "snap test". Pick up the fabric, holding the edge between your fingers as shown below. Then, gently snap the fabric between your fingers, pulling it tight as you do so. Try this on both sides of your fabric piece. You will notice one side will actually sound like a "snap" and will pull tight with very little give. This is the lengthwise grain. The other side will not have the "snapping" sound and will have a very noticeable give or stretch. This is the cross grain.
Having knowledge of fabric grain helps tremendously when piecing a quilt top. Knowing that fabric on the straight of grain will not stretch or distort and knowing that fabric cut on the cross or bias grain will, gives you a heads-up on where to begin your piecing and which edge to piece first.
How Starching Helps
In most cases, stretching is the enemy of accurate piecing. (A notable exception would be bias binding, where you need the binding to stretch to go around a curved shape.) For regular straight piecing however, the less stretch the better. Since the cross grain stretches quite a bit, its really helpful to use a starch product to stabilize the fabric and minimize stretching. When I started quilting, I was very resistant to using starch of any kind. I think I had some prior mental hang-up about it and didn't want to bother. When I finally decided to give it a try, I never looked back.
My favorite starch product is Mary Ellen's Best Press, I prefer it to regular starch or sizing, although I have all three in my arsenal. I use Best Press on my fabric before I cut it, or before I run it through the Accuquilt. Starch makes my cuts more straight and accurate with less distortion and it reduces fraying.
To apply starch, spray the right side of the fabric evenly and press with a medium-hot iron, NOT steam. You want to keep steam/water away from the fabric until after its pieced or quilted.
Pressing vs Ironing
To the layman, the words pressing and ironing are used interchangeably. They are not the same however, and the difference between them can make a world of difference in the accuracy of our piecing.
Ironing is what our mothers did to our father's cotton shirts. Its the process of moving the hot iron back and forth across the fabric to smooth out the wrinkles. Pressing is when you raise and lower the iron as you move from spot to spot. There is no sideways motion in pressing. A hot iron can easily distort fabric and that's a no-no when piecing quilt tops. Always press, never iron your piecing.
Pinning and Fabric Glue Pens
No discussion on accurate piecing would be complete without touching on matching seams and the best tools to use as we assemble those quilt blocks. Pinning is the usual method and of course, the go-to for most piecing jobs. I have found however, that sometimes a little something more is very helpful.
Enter Fabric Glue Pens! These are the best friend of accurate piecing and matching seams! How many times have you lined up your seams perfectly, pinned them carefully, and proceeded to sew them, only to find the seam shifted while sewing? This used to happen to me all the time. Now, I use these awesome little pens, put just a dab of glue on the seams I am matching and pin as usual. No more shifting and MUCH more accuracy. Below is an example of where I place the glue for this block from my Floral Bouquet topper and runner pattern. This block has many seams to match across the row and the glue pens are really helpful (in addition to the pins) in keeping the seams stabilized while I sew.
The pens shown above are from Sewline, but there are several other brands available. The colored glue dries clear and is water soluble. Refills are available (these are a must!). I have them all over my studio, one at each machine and also at my cutting table.
I hope these tips for perfect quilt piecing have given you food for thought and helped you further enhance your personal set of piecing techniques. If you have any other tips for accurate piecing, please share them in the comment section below.