Scant Rant: A Quarter Inch Seam Tutorial for Basic Sewing Machines

Since writing the original Scant Rant: 1/4" Seam Tutorial post, it was brought to my attention that not all sewing machines have adjustable needle positions.  Of course!  My first sewing machine, a basic Janome, was a great beginners machine with only one needle position.  I brought it out to find the scant 1/4" seam for those with this type of sewing machine.

Spending just a few minutes to find the scant 1/4" will save you many headaches in the future.  The term scant means just a thread shy of a 1/4".  If you never test it, you don't realize that your thread and the pressed fold take up some space in the measurement, usually resulting in blocks being short of their required finished dimension.

Video Tutorial here.

Placing a Piece of Tape as a Guide.
If the needle on your sewing machine is in a fixed position (i.e. you cannot shift it right or left), an easy way to find your scant 1/4" is to find the sweet spot and place a small piece of tape on the throat plate to serve as your guide.

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The Test.

1. Cut (2) 1 1/4" x 2" rectangles.  Sew along the 2" length with right sides together (RST), using the edge of your presser foot as your guide.  Press seam in one direction or open.  [Use your preferred pressing method - more details about how pressing method affects scant seams here.]
2. Measure the block to see if it is a 2" x 2" square.
3. If the block is short, you will need to place a piece of tape slightly to the left of the presser foot edge.  
4. If the block is too long, you will need to place a piece of tape slightly to the right of the presser foot edge.
5. Continue shifting the tape a little at a time until you find the sweet spot where the block measures 2" x 2".

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In the photo above, you can see how much I needed to move the tape to the left in order to achieve the scant 1/4".  This measurement may be just a few millimeters, but that dimension will add up to a larger amount with each seam you sew in the quilt.

After finding the correct location for the tape, line up your squares and/or rectangles to be sewn with the tape and (not the edge of the presser foot) each time you need a scant 1/4".  And keep the kiddos fingers from peeling it off!

Further Reading.
Part I:  Scant Rant: 1/4" Seam Tutorial for Sewing Machines with Adjustable Needle Positions
Part II: Does Pressing Method Affect the Scant Seam and Block Size?

Does Pressing Method Affect the Scant Seam & Block Size?

This is a continuation of the Scant Rant: 1/4" Seam Tutorial from earlier this week.  Jess of the Elven Garden raised an excellent point in the comments.  From her experience, blocks were always a little off until she started pressing her seams open.  And since scant seams account for thread thickness and the fold, I thought I'd play Scooby Doo Detective.

Does it make a difference if you press your seams open or to the side in your final block measurements??  Ahh, well.  The geek in me could not resist....

After digging out my only ruler with eighths and sixteenths marked on it, I cut several rectangles as I recommended in the test for sewing a scant 1/4" seam.  This time I wanted to check how pressing the seams open would influence the block size.

Here is the photo of the block using the needle in it's default position and pressing my seam open.  (I normally always press to one side because I am impatient like that.)  Although this is hard to photograph, I think you can see that this block is more than 1/16" too short.  Doesn't sound like much, but if every block is off this much, it can add up.

My next test was to sew the same block with the needle in it's adjusted position.  Now remember, I set this position by sewing my block and pressing to one side (explained here)....  It's pretty plain to see this block is too big by about 1/32" of an inch.

And again, test #3, the same block sewn with the adjusted needle position and seam pressed to the side.  Again hard to photograph, but this block is more accurate to 2" x 2" than the photo above.

So who cares?  Why on earth am I showing you all of this?  After all, we are talking about 1/16" and 1/32" of an inch here.  (I think I did mention we were going to be splitting threads right.... ha ha!)

The bottom line.  It does make a small difference.  That can add up if you are sewing lots of blocks together in, for example, a postage stamp quilt.  Here's my recommendation: find your scant 1/4" needle position using the pressing method you use most.  Or if you're into superhero precision, determine your needle position for both.

As for me, I'm no superhero.  

One more note.  Kati pointed out that not all 1/4" presser feet have space to reposition your needle.  Make a mental note to check that when you are selecting one for your machine.

  My Janome 1/4" foothas room to shift the needle to the right.

This Brother 1/4-Inch Quilting Foot does not appear to have much wiggle room.

Browse for other 1/4" presser feet models here.

Thank you for your comments!  I hope learning a little about this stuff helps everyone improve their accuracy just a little bit.


Further Reading.
Part I:  Scant Rant: A 1/4" Seam Tutorial for Sewing Machines with Adjustable Needle Positions
Part III: Scant Rant: A 1/4" Seam Tutorial for Basic Sewing Machines

Scant Rant: A 1/4" Seam Tutorial

Ok, so it's not really a rant per say.... but I wanted to ask if you've tested your 1/4" seam for accuracy? Don't make the same mistake I did!  For years, YEARS!, I sewed with a true 1/4" seam.  I never took the time to find the scant 1/4" and as a result, my seams and resulting block sizes were always a little off.

Spending just a few minutes to adjust your machine to a scant 1/4" will save you many headaches in the future.  The term scant means just a thread shy of a 1/4".  If you never test it, you don't realize that your thread and the pressed fold take up some space in the measurement, usually resulting in blocks being short of their required finished dimension.

Video tutorial here.

Here are some helpful hints:

Presser foot.  My machine comes with two default general presser feet.  The zigzag foot and satin stitch foot are used for most stitches and straight line sewing.  The 1/4" foot is specifically for quilters trying to sew that perfect 1/4" seam.  If you don't have a 1/4" foot already, I highly recommend getting one.  The black guide on the right hand side of the foot helps position your fabric by butting the edges of the squares right up against the guide.  I sew with this foot 99% of the time.  My accuracy (or should I say consistency) is much improved using the guide.

Needle Position.  Many times, the needle position will need to be adjusted from it's default position to achieve the scant 1/4".  In the photo above, you can see that when I try to sew a 1/4" seam with the needle in it's default position, the block is slightly shy of the 2" x 2" block is it supposed to be.  It takes a little time to play with shifting the needle to find where it hits exactly on 2".  After finding the correct position for the scant 1/4" seam, adjust your machine to that needle position every time you sew.  It will seem like a hassle at first, then it will become an automatic part of sewing, just like grabbing that diet coke before you begin.  :)  I find it helpful to have a sticky note with the adjusted needle position written down stuck to the side of my machine.
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The Test.

1. Cut (2) 1 1/4" x 2" rectangles.  Sew along the 2" length with right sides together (RST).  Press seam in one direction.
2. Measure the block to see if it is a 2" x 2" square.
3. If the block is short, your needle will need to shift to the right.  
4. If the block is too long, your needle will need to shift to the left.
5. Shift the needle one or two notches at a time until you find the sweet spot where the block measures 2" x 2".

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Further Reading.
Part II:  Does Pressing Affect the Scant Seam and Block Size?
Part III:  Scant Rant: A 1/4" Seam Tutorial for Basic Sewing Machines