To make your ¼ inch seam accurate we
must address three basic steps.
Step One: Accurate Cutting with a Rotary
Cutter
AKA
Preventing the Dreaded “V”s and “WOW”s
Working with
the true straight grain of your fabric will make sewing your pieces together
easier and more accurate.
If you straighten an edge using only a single fold or
the selvedge edge as your guide then you are more likely than not to get strips
that have a “V” or “WOW” in them.
All sub cuts
made from the resulting strips will be slightly off grain making them want to
twist as you feed them through your sewing machine.
This will affect your ability to sew a
consistent ¼ inch seam.
To prevent
this place the fold of your fabric towards the top of your cutting mat.
Fold the
selvage edge towards but not all the way to the fold at the top of your fabric.
Measure from
fold to fold with your quilting ruler.
Use an easy
measurement to view on your ruler such as anything on the ½” or 1” line.
When you get the same measurement across the
length of your fabric then you are “On Grain” and ready to straighten an edge.
Don’t try to straighten more than 25” to
30” at a time.
It’s better to re-measure and re-straighten as required.
Now…use
one of the long horizontal lines on your ruler to line up to the bottom fold of
your fabric. The other lines should be square to your top fold.
Trim a little bit of fabric off the side to
“straighten an edge.
If you are
right handed you will straighten from the right and cut your strips from the
left.
If you are
left handed you will straighten from the left and cut your strips from the
right.
When cutting
your strips be sure that the line you are measuring is ON TOP of the straightened edge.
If your measurement line is on the
outside of the cut edge you will “lose” approximately 1/16” to 1/8” of fabric.
It doesn’t seem like much but by the
time you have cut eight strips you have “lost” up to an inch in the accuracy of
your measurements.
No matter how well we sew if our
cutting is out our blocks will still be the wrong size.
*Hot Tip:
If you square your body to your
ruler it won’t slide out of place and you will not need as much pressure to
make your cuts.
This is accomplished by simple physics in that all your weight
is automatically transferred down into the table so that your ruler stays in
place and your cutting hand has more power without more pressure.
To be sure
that you are square to your ruler stand with your feet flat and side by side
and line your “Belly Button” up to the hole in your ruler.
It’s easy to
remember because it will make you laugh…and it works!
Step Two: Accurate Sewing
I generally use
50 weight cotton thread with a sharp needle when piecing cotton.
Good needle
choices include Quilters size 75/11, Jeans Denim size 70/10 or Microtex Sharp size 80/12.
If your
fabric is a blend of poly/cotton you may use poly/cotton construction thread.
If quilting
with polyester, piece with 50 weight polyester thread.
*Please Note
Though weight is the most common way
that we compare threads it is only accurate when you compare threads within the same category and with the
same number of ply.
For instance a 50
weight cotton three ply will be thicker than a 50 weight cotton two ply as the
thread is 50 weight per ply.
A cottonized polyester will be different from
a filament polyester.
This subject is
covered in depth in my Lecture/Demo
All
About Thread
Now for the most confusing part about
¼ Seam Allowances
A measured
¼” is the measurement that is on a ruler.
Most
patterns, books etc. will tell you to use a ¼ inch seam allowance to piece your
quilt.
It is
assumed that quilters know to piece with a “scant” or “quilters” ¼ inch seam
allowance.
We sew with
“just under” a measured ¼ inch to allow for the width of our thread as well as
the fold over of the fabric in our seam allowances.
Most sewing
machines can sew a basic scant ¼ seam with the use of a Standard Foot or ¼”
Piecing Foot
You may need
to adjust your seam allowance according to the thickness of your fabric and the
thickness of your thread.
Pressing your seam allowances open will give
you a slightly different measurement than pressing all seam allowances to one
side.
Simple
designs consisting of pieces that are all the same size can be pieced with a scant
or generous, (measured), ¼ inch seam.
The more complex the design, the more
careful you need to be to sew an accurate seam allowance.
The moveable needle position in straight stitch on our computerized sewing machines allows us to fine tune the ¼ inch seam to achieve perfect results for every project.
A good way
to set your machines needle position is to sew a test block consisting of six
strips, 1 ½ inches wide by 6 ½ inches long.
Use leftover fabric from the quilt you are
making to ensure accuracy. Press seams the same way they will be pressed in the
quilt, (open or to one side.)
Measure your
completed square.
It should be
exactly 6 ½” square.
If it is too small or too large then adjust your seam allowance
accordingly.
If you do
not have a computerized machine there are a variety of ¼” guides available to
help you sew an accurate seam.
I find that
a piece of Moleskin (a thick cushy adhesive bandage), available from any drug
store, stuck to the bed of your machine to the right, front of your needle,
will allow you to sew more accurately than a flat tape such as masking tape.
Sitting
At Your Sewing Machine
Sitting
correctly at your sewing machine will reduce stress to your body and allow you
to sew more accurately.
If
you are sitting too high or too low you will not be able to sew a straight line
because your depth perception will be off.
You should
be able to reach out with your arms at a 90 degree angle and gently drop your
hands into place.
Center your body to the sewing bed.
“Driving a Straight Road”
Look ahead
to where you want to be sewing. Keep your eyes in front of the needle.
If you
look at the needle (it can’t jump out
and get you) then you will drive a crooked line.
Look to where you want to
go and you will stay on the straight and narrow.
Step Three; Pressing Matters
It’s quite
simple really.
Press, don’t
iron. Let your iron do your work for you.
Set your
seams from behind by putting heat and steam (if desired) on top of the seams
before trying to press them open or to one side.
Use the
weight of the iron to either push the seam to one side or press the seam open.
When
pressing the seam to one side, have the fabric you want the seam to lay towards
facing up and push the top fabric towards the seam allowance. Your seam
allowance will be pressed to the correct side with no little creases.
By
using these simple steps you will have wonderfully accurate ¼ inch seams.
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