What is a “Scant ¼ inch” and why is it important in quilting? This is my #1 Tip for accurate quilt piecing! Especially when piecing multi-part or complicated quilt blocks. I frequently get emails where people are asking why their pieced quilt block comes out too small. 99% of the time, the cause of the problem is that their seam allowance – or seam width – is too wide. If your pieced quilt blocks consistently come out too small, this tip may help solve that problem. I’ve talked about this for years, but just updated the post for 2022 with more details and photos.
Piecing with a Scant quarter-inch seam allowance can make a huge difference in the accuracy and appearance of your finished quilt. Here’s what it is and why it matters.
As you probably already know (but maybe not if you’re new to quilting): a ¼″ seam allowance is the gold-standard in quilting. All quilt patterns are written with a ¼″ seam allowance built into the cutting and piecing directions (unless otherwise noted.)
Keeping your seam allowance consistent is an important key to all good-looking finished quilts but using a scant quarter-inch seam – especially when piecing individual quilt blocks with a lot of seams – is even better. Let me explain why it makes a difference.
Above is are three different seams sewn on the right side of a drawn straight line. For the seam on the far left I used a generic presser foot with the needle centered. For the seam in the middle I used a quarter-inch foot attachment. For the seam on the right I used a quarter-inch foot attachment and adjusted my needle .75mm to the right.
Here is the difference. On the left you can see that the seam allowance is actually slightly bigger than ¼″ – it falls outside the ¼″ line on the ruler. That may seem “close enough” but actually can have a big impact on a pieced block.
In the middle, the seam is exactly ¼″ away from the drawn line. It’s an accurate ¼″ seam allowance.
On the right you can see that the seam lies just slightly – maybe only a thread’s width – inside the ¼″ line. This, my friends, is a scant ¼″.
The reason this makes a difference is that by the time you open up the pieces and fold one side over (press seams to one side – which is what I recommend) you lose a tiny little bit of real estate with each seam because of fabric bulk, affecting the size of your blocks by making the pieced blocks slightly smaller. Multiply that by numerous seams and a block can shrink as much as a ¼ of an inch let alone an entire quilt.
HOW TO GET A SCANT ¼″ SEAM ALLOWANCE
First: Measure the consistent seam allowance you get with the foot you use.
Typically lining up the edge of your fabric with the right side of your presser foot is a good guide for keeping your seam allowance consistent. Some newer sewing machines come with a specific ¼″ quilter’s foot with a seam allowance marked by the edge of the presser foot being ¼″ away from the needle.
If your machine does not have a dedicated ¼″ foot you will need to measure where the ¼″ seam lines up with your most common presser foot.
And even if you do have a ¼″ foot, check how wide the seam is.
Second: move the needle slightly to the right to make it a ‘scant’ ¼″. Measure again until your seam stitching is just inside the ¼″ marking on a ruler. This is my preferred method.
Word of warning: make sure you are using a foot and a stitch plate where there is room for the needle to move to the right.
Here’s a handy tool for checking your seam allowance width: The Perfect Piecing Seam Guide* from Perkins Dry Goods is perfect for this process of helping you find a scant ¼″ seam allowance. (This video demonstrates how easily it works.)
Some people will also use a piece of washi tape or masking tape as a guide.
Another simple and inexpensive option is a magnetic seam guide.
This seam guide is easy to place and remove, but holds steady as a fabric guide.
What about a straight-stitch machine where the needle doesn’t move?
Last year I demo’ed sewing with the Baby Lock Accomplish straight stitch machine. Moving the needle position is not an option for this machine so I did a little research.
The machine does come with a ¼″ foot (above on the left), but because the machine sews so fast, it was hard to keep a consistent scant ¼″ seam allowance. It didn’t matter for piecing long strips or sewing borders, but caused some issues for piecing intricate quilt blocks. After some training from Baby Lock, I decided to use the general purpose straight-stitch foot paired with the adjustable seam guide (above on the right).
Here’s another view. I used the attachable seam guide that comes with the machine and set the guide just inside the ¼″ mark on the metal needle plate (see photo above). This gave me a great scant ¼″ and made piecing blocks really easy and accurate. And I actually really like that the seam guide sticks out farther ahead of the foot and is easer to line up my fabric next to it well before it heads under the foot and feed dogs.
Sewing Machine Feet for ¼″ Seam Allowances
There are a variety of ¼″ quilting feet available these days. Check and see if one comes with your machine, and if not, if a new foot is available for your model.
Here are some ¼″ quilter’s feet options from Baby Lock. I love the detachable snap-on feet made by Baby Lock – they’re sturdy and well made, yet reasonably affordable. AND they are interchangeable with all of my Baby Lock sewing machines. Including the Accomplish – which is a mechanical straight-stitch machine. To use these on the Accomplish you will need to buy a Master Shank attachment (part BLQP-MB)
My favorite and most often used foot is the new ¼″ Quilting Foot with black Guide. This guide is curved so it doesn’t catch on other seams or corner points. It’s also a heavy duty enough for sewing through multi-layers and has a wider needle hole, making it easy to move the needle to get the scant ¼″ seam allowance.
Keep in mind – you don’t have to have a specific ¼″ foot to get an accurate ¼″ seam allowance. For years sewing on my old 1979 metal machine I only used the basic foot the machine came with and adjusted my needle close to the edge of the fabric.
Some newer high-tech Baby Lock machines also have a Quilting Stitch that is set ¼″ away from the edge of the General Purpose J foot. I only just recently learned this!
You might even try an unconventional foot – like this Blind Stitch Foot with adjustable guide!
So check your machine model – or ask at your sewing machine dealer about how to get the best ¼″ seam for your machine. There may be built in tricks and tips that you don’t know about your model!
Times you don’t want to use a scant ¼″ seam allowance:
- when you are supposed to sew directly ON a line or guide – such as when foundation paper piecing.
- You also don’t need to worry about a scant ¼″ seam allowance when you are piecing one-block quilts – like simple patchwork quilts – where all of the blocks are cut to the same size.
- I would avoid a scant ¼″ if you’re sewing with flannel or other loosely woven fabric that might fray.
So go get out your ruler and measure your seam allowance. Making adjustments may be as simple as moving your needle one notch to the right. This simple adjustment of sewing with a scant seam allowance will make a big difference in your piecing. Especially if you’re piecing smaller, detailed blocks.
Give it a whirl and let me know if it makes a difference for you.
This post is sponsored by Baby Lock Sewing Machines.
Check out more of my favorite quilting tips here.
There are so many smaller tricks, tips and techniques that will help with accuracy and make your quilt blocks look perfect!