Accurate 1/4″ Seams

How important are they?

Well, accurate seams aren’t important if you don’t think they are. It’s your quilt, your hobby, and if you’re comfortable with the way you work, remember all the sayings about quilt police!

On the other hand, if you quilt in groups (round robins, charity quilts, or the like), projects are easier if everyone uses the same standards. In this case, the standard is the 1/4″ seam. Triangle points are preserved, blocks fit together easily, and seams don’t ripple and need to be “quilted out.”

A lot of quilters make blocks, especially half-square triangles, oversized and then cut them down. This works and I do it myself sometimes. But sewing with precision in the first place saves time later. Accurate piecing means rarely trimming blocks. Don’t do things twice if you don’t have to!

You might think accurate piecing is just a matter of sewing the right width seam allowance. That’s a big part of it, but it isn’t the only part. Accuracy actually permeates the whole process.

It starts when you prep your fabric. Some people prefer to use washed fabric and some don’t. I strongly prefer washed, due to sensitivities, but I don’t see it as a religion. Either way, soon you will cut fabric, and before cutting, you need to press it.

I press carefully with a hot steam iron, because cutting is more accurate on flat fabric. Many people recommend starching fabric to stiffen it, making it easier to manage. I do now and then, especially if I’m working with a cotton that’s flimsier than usual. Here’s an interesting note from Judy Laquidara of Patchwork Times. She has a comparison between Best Press, a product many quilters swear by, and Niagara’s non-aerosol spray. As it turns out, Best Press IS starch, and in fact is much more expensive than Niagara. I’m cheap. I know what I’ll buy!

Okay, you may think once your fabric is pressed, you’re ready to cut. But wait! There’s more!

When’s the last time you changed your rotary cutter blade? If your cutter blade is dull, it will drag the fabric rather than slice through it. You may need to cut through parts multiple times, risking moving your ruler slightly. A sharp blade will give you better cuts with less force. A bonus is that sharp blades are less dangerous, too!

Many people do cutting on their sewing table next to them. I’ve found I don’t get good cuts that way. If I am sitting rather than standing over my work, the angle of cut isn’t correct. Instead I use my cutting table, and I count the extra steps to get there as part of my exercise!

My cutting surface is a comfortable height for me to use while standing. It’s a plastic-topped, folding “buffet” table, the type that can be found at most discount stores. It is much too low by itself, but I have it raised with PVC pipes slipped over the legs. The pipes are cut to raise the table about 5 inches. Other people find that bed risers work well to raise their table. The extra height helps with comfort, but it also helps with precision, because I’m not bent so far over my work.

Lighting is another element. Enough light, in front and above you, makes your work easier and more precise. I have LED light strips on either side of the room where I cut.

Okay, you have a sharp blade, and you’re cutting with plenty of light at a table the right height. Now what? There are lots of sites than can give you tips for accurate cutting, including this and this.

But two more tips from me: first, I rarely cut across the grain, selvage to selvage. Along the selvage is more stable, so whether I’m cutting border strips or strips to subcut for piecing, I cut with the grain. If the selvage is gone, you can tell which direction is “with” the grain by which one has less stretch when you tug it. Second, don’t try to cut through more than four layers of fabric at a time. More layers are harder to cut through, requiring more force from you and increasing the opportunity for mistakes.

And one product recommendation: I really love my June Tailor Shape Cut ruler! I think my cutting improved when I started using it.

When you take precisely cut pieces to the sewing machine, how can you get good seam allowances? Again, ergonomics, or your comfort, plays into it. If you can, use a desk chair with adjustable height. You need to be able to see and reach your workspace easily to have good control.

Pins: sure, they take time. Time to put them in, time to take them out… they seem like a hassle, and better avoided when possible. I feel that way, too, and I rarely pin small units. But when I assemble blocks I usually use them. And when I sew long lines, such as rows of blocks or borders, I pin a lot, every couple of inches. Thin pins are best, as they don’t distort the fabric and are easier for your machine to cross if you don’t pull them first. Pins also make it easier to fudge when the two pieces don’t match up exactly right.

I use a 1/4″ foot to make my seam allowances better. It has a little “fence” to guide my fabric edge. Still I need to know whether to nudge my fabric against the fence or leave a thread width away from it. Some machines have adjustable needle positions, but not all 1/4″ feet can accommodate a change in position. If not, you still need to be in charge.

If you don’t have a 1/4″ foot, there are a lot of sources for tips (here and here, for example) in getting a better seam allowance. This doesn’t always matter a lot when just sewing squares, but it does matter a lot when sewing triangles.

And no, you’re not done yet! Pressing a stitched unit or block is the last part of the puzzle. As with fabric prep, when you press units, use an up and down motion, rather than dragging the iron across. Most sources recommend pressing toward the darker fabric. Sometimes this is practical and sometimes not. You can find more tips for pressing here and here.

As you can see, there are a lot of different elements that play into piecing accuracy, not just your time at the machine. See if some of these tips can help you. Little changes can add up to a lot!

Do you have more tips for improving accuracy? Or for improving attitude when accuracy is hard to find?


7 thoughts on “Accurate 1/4″ Seams

  1. leisaval

    I do all of my piecing on Brown Betty. She is a 1948 Kenmore rotary straight stitch. She has a perfect 1/4 inch foot. No gated feet for that model, but I use a magnetic guide. ( I do love my gated Bernina foot, and hate the cheap knock off). There is so much metal in the Kenmore it us immovable once placed, It has powerful feed dogs which are “grippier ” (sharper teeth) and more surface area (there us extra purchase in front of the presser foot) than my beloved Bernina. It pulls everything very straight through. As a straight stitch, it has one hole.

    I am a big fan of glue basting. I rarely press my seams open, so if you do, it will be frustrating. Keeping both top and bottom fabrics together allow for fast accurate feeding at key match points and for long runs Also, glue stabilizes biased edges, no pricks, no bleeding and no pin management. Really works wonders in chain piecing as pieces stay discrete (no catching on neighbors).

    I use a spray bottle to spritz blocks and a teflon coated fiberglass mat. It allows the iron to glide effortlessly over seams, and efficient conducts heat to really get them flat–as such you could place a book on top and the residual heat would continue to shape your block.

    I’m no expert but I adopted these methods to help be achieve better results and I am happier with my results.

    1. Melanie McNeil Post author

      It sounds like you’ve figured out some great techniques to use. I use glue fairly often but have not used it for basting. Thanks for reading and commenting.

  2. Yanic A.

    So you steam press? I steam press and I was told by many that I was doing it wrong. Something about the steam shrinking the fabric. I never found that it did. It,s nice to read about someone else pressing with steam. Great post!

    1. Melanie in IA Post author

      Thanks, Yanic! I do use steam almost always. I’ve read not to, also, and never have understood that. Of course I wash my fabrics first. Maybe if you don’t there is some shrinkage — I don’t know.

      The main thing about pressing, of course, is not to pull at the fabrics with the weight of the iron. But that would be true whether you steam or not.

      Thanks for taking a look!

      1. Yanic A.

        I always set seams and then finger press before even using the iron, so I never pull. I don’t wash my fabrics though. I like them straight off the bolt. But hey! If I’m steaming everything, theoretically, they are shrinking even so… LOL!

  3. Laura C

    SO, where was this post last week?! Thank you for saying that they only matter if you think they matter (and then for bee blocks). I’ve thought and thought, and as long as my blocks match up (that is consistency) I don’t give a flying seam rip whether my 1/4” seam is accurate. I will continue to only sweat it for bee blocks. 🙂 Thanks for the hints!

    1. Melanie in IA Post author

      Hi Laura! It was still in my head last week! Accuracy does matter to me, but I think that’s mostly to satisfy my analytical side. I love looking at liberated quilting a la Gwen Marston, but I don’t want to work that way, for the most part. But I’m not a perfectionist, just a pretty-goodist. So I fudge and squish and trim edges and ignore places where seams don’t meet up right.

      One of the reasons I wrote the post, though, is because there really ARE so many factors that affect it. If a person is only focused on one or two, they still may be frustrated by their work. Small changes in lots of the process can make it less frustrating (less ripping!) and more fun.

      Thanks for reading and commenting.


Thanks for your comments. I don't check them often. Please email me if you have questions.

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.