Machine Piecing Hexagons - Introduction to "Y" Seams

How do you feel about Y-Seams? Does the mention of Y-Seams have you quaking in your boots and heading for the hills? Well I'm here to take away the fear and stigma of the dreaded Y-Seam and help you build some serious skills. There are lots of tutorials and patterns that avidly proclaim, “No Y-Seams!” as a selling point and an invitation to make something that looks harder than it is. Did you know it's really not that tricky to machine-piece a patchwork hexagon quilt? In this post I'm going to break down the steps to piecing "Y Seams" with your sewing machine and show you how do-able they really are.

I’m all for short cuts in quilting. I’ve built my style around fast and easy quilting short-cuts, but I’m here to tell you, Y-Seams are not as scary, or as difficult, as they’re sometimes made out to be! The skilled use of a good Y-seam will enable you to create some outstanding quilt designs. Another bonus is better fabric placement. For example, instead of piecing half-hexagons where the fabric pattern is cut in half and has a seam running down the middle, a pieced hexagon can really show off a great fabric design element or fussy cut.

At the same time, I'm not saying they’re easy. Y-seams do require a different approach then regular seams. Look at it as another skill to add to your repertoire. With a little bit of practice, this technique becomes natural and with very little extra effort.

What is a "Y-Seam" in Quilting?

“Y Seams” is often a term filled with fear and loathing in the quilting world. Another term for a Y-Seam is an "inset seam". Basically defined, a Y-seam is found where three pieces of fabric, and hence, three seams, intersect with each other, typically forming a Y shape. Here are some examples:

The intersection of pieced Hexagons will have three 60-degree angles.

Three 60 degree diamonds sewn together using a Y seam in the middle (see where the three diamonds intersect ) will create a six-sided hexagon.

A Lemoyne Star (below) will sometimes have a 90-degree square that intersects with two 45 degree diamonds (notice the 4 corner squares of this block) that will also form a "Y-seam".

I’m excited to help you build your skills and confidence in machine piecing Y-seams so that you can add another weapon in your piecing arsenal.  

In this post we're going to talk specifically about sewing together Hexagons, using Y-Seams, with a sewing machine. (This method also works if you want to hand-piece your hexagons.)

Cutting Fabric Hexagons

First, let's talk about cutting Hexagons. Hexagons can be cut in multiple ways:

Important Tip: Be aware that there are multiple ways to measure a hexagon block. Some measurements are taken from the height of the hexagon from one straight edge to the opposite straight edge. For example, this hexagon below has a height of a 3" finished hexagon (or 3 ½" unfinished).

Other hexagons (particularly in English paper piecing) are measured by the finished length of each side. If using that measurement, the hexagon above would be a 1 ¾" hexagon.

It can be confusing, so when you're working with a pattern, make sure you know which measurement they're referring to.

For piecing a one-piece patchwork block/quilt (which we'll focus on in this post), the only thing that matters is that they are all the same size. I'll be using these 3" (height) hexagons.

The easiest method for cutting hexagons is a die cut machine - no measuring, just run your fabric through the machine. AccuQuilt has a lot of hexagon die options. I used the large Hexagon die from AccuQuilt for cutting most of the blocks on this hexagon crib quilt. Be advised that there is more fabric waste and it’s harder to fussy-cut with a die, but it is a great time-saver when you need to cut a lot of hexagons, quickly.

There are a lot of Hexagon rulers and templates for custom cutting hexagons. I like this acrylic hexagon ruler because it gives you 5 different size options with one ruler.

With a hexagon ruler or template – if you’re cutting multiple hexagons from the same fabric, it’s easiest if you cut a strip with width the same size as the height of your unfinished hexagons. Then you only need to cut 4 more edges.

Machine Piecing Hexagons - sewing them together:

Prepare the Fabric Hexagons

The most important thing to keep in mind: because we are always sewing with a consistent ¼” seam allowance, seams will always begin and end (but not intersect across each other) a ¼” away from each edge.

Where the ¼" lines intersect is that starting and stopping point.

NOTE: A ruler/template with a hole for marking the ¼” intersection is a great timesaver. They can be used for any size hexagon (including 60-degree diamonds) since it is only the intersecting point at the 60-degree angle, not necessarily the whole shape itself, that needs marking.

Mark where the ¼” intersections will happen on the back of your fabric pieces.

How to Machine-Piece Hexagons with Y-Seams

To practice machine-piecing Y-seams with hexagons, cut an assortment of hexagon blocks. (I recommend 4” or bigger for practicing since it’s easier to manipulate the fabric if you’re just trying this technique for the first time.)

Lay out your hexagon blocks until you get a pleasing arrangement of color and fabrics.

IMPORTANT TIPS:

• Lightly starch and press your hexagons before you start piecing. This will help with accuracy.  
• Avoid fabrics that stretch easily like voile, lawn or linen as it’s easier for the blocks to get distorted on those bias edges.
• Shorten your stitch length to 2.0 to make it easier to stop and start on the marked dots.

Hexagon strips are pieced together in vertical rows from top to bottom.

Sew Hexagons in Rows

Starting with first two hexagons in a row, match-up blocks, right sides together as you would patchwork squares.

Instead of sewing from edge to edge, place your two pieces under the presser foot and before you drop the foot, manually drop the needle into the dot that marks the ¼” intersection.

Then drop the foot, sew forward a couple of stitches and then backstitch. Carefully sew the seam, stopping at the second mark for the ¼” intersection. Take a couple of back stitches, careful not to go past the marked dot.

(I rarely use backstitching in quilting, but this is one time it is important to do so.)

Important: Make sure you do not sew beyond the ¼” mark, otherwise you will have a tuck in your Y-seam (see below) and your blocks won’t lie beautifully flat.

If this happens, it’s not a crisis. Just take your seam ripper and rip out the offending stitch. If you’re having trouble always hitting the second ¼” mark, shorten your stitch length a little, or remember to stop right before the ¼” mark. Always better to go a little under than too far over.

Finish sewing all blocks, in order, to each row. Finger-press the seams open at this point.

Y-Seam Piecing Short-cut – Washi Tape

If you don’t want to have to mark the ¼” point on the back of every single hexagon, especially if you are sewing a lot of hexagons together, here is a snazzy short-cut for when you’re piecing.

Begin with one hexagon that is marked to use as your reference guide. Follow the beginning steps outlined above where the needle is dropped into the ¼” mark. Drop foot, making sure the outside edge of the fabric is lined up with your ¼” guide/side of your foot.

Using non-tacky tape (like washi tape), mark the top angle of the hexagons with a piece of tape. (See picture – this shot is from behind the machine.) This way, for future seams, you can just line up the hexagons with the edge of the tape, drop your needle and start sewing!

Repeat the process with the bottom edge – sew to the bottom ¼” point and stop. Place another piece of tape along the bottom edge of the hexagons. This is how you will know where to stop your seam and backstitch.

Now you can piece all of your rows together quickly – starting and stopping at the ¼” point of each seam. Finger press the seams open.

Sewing/Piecing Hexagon Rows Together

After all vertical column rows are sewn together, lay out the rows for a better visual of where the next seams will go. (Trust me on this one – it’s easy to get confused and start sewing hexagon sides to the wrong place. A visual layout will help a lot.)

That zig-zag space between the two columns is where the next seam will go.

Flip Row B over right-sides together with Row A, matching up the two edges that need to be sewn together and put a pin in to help you remember that’s the side you’re stitching.

Start sewing (and backstitch) at the ¼” mark (you can use the Washi Tape guide for the first seam) and sew to the next ¼” mark (this time easy to spot because stitches are already in place), and backstitch. Cut the threads.

Make sure you sweep the edges of the third hexagons out of the way, so that you don’t accidentally catch them in the seam. I like to stick a pin at this point to hold the third hexagon out of the way and also provide a visual so I can see where I’m going to stop and backstitch.

Pull rows out and line up the next two edges to be sewn together. Again, sweep the previous hexagons out of the way, drop needle at ¼” point (don’t catch the previous seam) and sew to the ending ¼” point.

Repeat the process with each seam to sew the two rows together.

Here's what it looks like to add the third vertical row. Repeat the process: lay out the rows next to each other so that you can see what seam you'll sew first. Match the pieces right-sides-together and put a pin in the place where the first seam will be sewn to help you remember where to sew.

This is definitely a little more tedious that sewing together regular patchwork in one straight line, but the more you practice the easier it will get and you’ll find yourself getting into a good rhythm.

Pressing seams

Leave all the pressing until the end. Press seams from the back with seams going in the same directions (i.e. right, and down.) Or, press seams in a rotating ‘swirl’ with open seams creating a mini tumbling block at the intersections, if you want them extra flat. (I, personally prefer to just press the seams in one direction without the swirl, because I feel like it stabilizes the intersection a little better.)

Then flip over and press from the front, making sure all seams are nice and flat.

Finishing: once my rows are all pieced, if I wanted to use this as a quilt with straight sides, I would square-off my edges.

NOTE: You can see above that I cut one hexagon in half and used it as a top and bottom piece in one of the rows, so that it could eventually be a straight edge. I decided I don’t recommend this, at least for smaller hexagons. The edges didn’t line up straight and this distorted the piecing as well. Hey, we’re all experimenting together on this!

Have you ever tried machine-piecing hexagons using Y-seams? I hope this little walk through gives you the confidence to give it a try!

A final recommendation about machine-piecing hexagons: if you’re just trying it for the first time, start with bigger hexagon pieces. I’ll be easier to manipulate the fabric and bigger blocks mean the project will come together more quickly.

Check out Part 2 where we build on this skill to machine piece 60 degree diamonds to make a traditional Tumbling Block design.

And in Part 3 I'll show you how versatile 60 degree diamonds are and how you can use them to piece stars.

This post is sponsored by Baby Lock Sewing Machines. I've been sewing exclusively with Baby Lock machines since 2017 and I'm a huge fan.

If you're looking for recommendations for buying the right sewing machine for a beginner or ideas for upgrading your current machine,  I've got a post here on how to choose the perfect sewing machine, for any level or budget.