Piecing 101: Quarter-inch Seams
July 11, 2014 § 19 Comments
Quarter-inch seams. Why are they so important in quilting? While consistent seam width is important for simple quilts. It’s the good ol’ 1/4-inch standard that will guarantee better success when making complicated blocks.
Your machine may have one of these types of 1/4-inch presser feet above.
1. The foot that came with my Brother PQ-1500s.
2. The foot that was sold to me for my Featherweight when I took a maintenance class.
3. The foot I purchased off the Internet and comes with some brands of machines.
4. The method that my Janome uses to achieve a 1/4″ seam is a pre-programmed needle position. No special feet involved.
No. 1 is by far my favorite presser foot with No. 3 as a close second. No. 2 is my least favorite and I would rather go without a 1/4-inch foot altogether than try to work with it. And I could live with No. 4 if I had no other choice, but I would certainly prefer a special 1/4-inch foot far & above a pre-programmed needle position.
So let me explain why I have the opinions I do. You are free to form your own opinions and are under no obligation to change them just because I happen to prefer something else. Use what works for you.
I like presser foot No. 1 because it shows me where a 1/4″ seam is but doesn’t force me to follow it if I don’t want to. And the second bump on the right side is the guide for a 3/8″ seam, which is what I generally use when sewing binding, sort of. Or maybe making bags or some home deco type of item. It’s my go-to all-purpose foot. I like that extra little bit of width in the back to keep the fabric stable, yet it doesn’t intrude on achieving a 1/4″ seam when necessary.
Foot No. 2 is my least favorite because I’m not quite sure where a 1/4-inch really is. It has a hard edge guide on the right side that forces the fabric to go no further. What if I wanted to sew a 1/4-inch top stitching line? I can’t do it because the metal bar is in the way.
And do you see that little gap between the foot and the bar? It seems to ever so slightly slant out further in the front than in the back. So is the 1/4-inch in the back or the front? It makes me feel like I am constantly pulling the fabric one way or another when I’m sewing. And where is a scant 1/4-inch? That bar is in the way and I can’t see what I’m doing.
As you can tell, this presser foot really gets on my nerves.
And that is sort of why I am not overly fond of the pre-programmed needle position in No. 4 either. It’s much too fussy and I’m still not quite sure what is a full 1/4-inch and what is a scant 1/4-inch. I’m a visual person and I like to “see” what is going on. I don’t like computers telling me what they think I want. In quilting anyway. But I could learn to get used to it if I had to. It’s better than nothing.
So, now I’ve thrown another concept out there. What’s the difference between a full 1/4-inch and a scant 1/4-inch? A full 1/4-inch only includes the seam allowance from the thread to the cut edge without including the thread. A scant 1/4-inch is anything less than that. How scant does it need to be, you ask? Well. That depends on the thread you are using and the thickness of your fabric. It’s something that you need to learn for your own personal machine and your thread & fabric choices.
The above photo shows my scant 1/4-inch seam that includes the thread. It is what I need with this thread, and this fabric on this machine.
The objective is all about making the math add up. In theory, the above image is five 2 1/2-inch finished size squares sewn together plus a 1/4-inch seam allowance on each side. So the width needs to equal 5 x 2.5 + .5 for a total of 13 inches. When you sew it all together is your block at this point measuring 13 inches? What if you had twice as many seams and lost only 1 millimeter for each seam? Eight millimeters adds up to nearly a centimeter which is approximately 3/8-inch. So your block would be short by that measurement and it would be difficult to match up to whatever the next block might be. Certainly you can fudge. But then you may be sewing blocks together with only an 1/8-inch seam or less in places.
Additionally, if you have thick thread, every little millimeter of variance adds up. Thick fabric when pressed to one side is impossible to make completely flat without loosing a couple of millimeters or more. That little fold of fabric can take out a couple of millimeters, easily. Add on a few more seams and suddenly your block is not the size you thought it was going to be.
One trick to making flatter seams if there are a lot of tiny little seams is to press them open. Then only one fold of fabric is being taken in with the seam allowance rather than two. I don’t know if you can see the difference in the photo above. The left is the flattest seam and the right is the bulkiest seam. The middle is the average seam pressed towards one side and of medium thickness.
I prefer Aurifil 50-weight thread. It feels just a hair thinner than most thread and therefore adds just a smidge less to the seam allowance. The topic of thread could be a whole separate discussion.
In continuation of talking about 1/4-inch presser feet are the feed dogs underneath the feet that help you achieve the seam that you desire. These are the feed dogs on the above machines.
1. Brother PQ-1500s
3. My grandmothers Singer 15-91
4. Janome Horizon 7700
This is one of the reasons I prefer older, vintage machines for piecing quilts. Numbers 2 & 3 are vintage Singer machines. Do you see how close the feed dogs are? And that there is one that is extremely close to the needle hole? This helps to keep the fabric straight and flat while sewing small seams.
My Brother happens to follow in the footsteps of these vintage machines and one of the reasons why I love it so much for making quilts.
The Janome’s feed dogs are wider and farther from the needle hole. Which is not as favorable for sewing together small pieces of fabric with small seams. It’s great for sewing clothing and decorative stitches where you may have a lot of fabric being fed through. But it’s not so great for tiny little pieces with tiny little seams. To me, it feels like the fabric isn’t as stable under the presser foot as it could be. It feels like it has a little more room to slide around and shift during the process of sewing.
Well, I hope you found this interesting or useful. I could continue with more about leaders & enders, single hole plates vs. zig zag plates and thread. But this post is getting too long already. So those may need to be separate topics another day.
Meanwhile, sew on!