Types of Sewing Machines/Sewing
101 (there will be a test)
A typical home sewing machine does not sew banners
well because it’s unable to feed the material rapidly and consistently through the needle. Home machines create small inconsistent stitch lengths and lack pulling power. Their sole source of feed movement comes from the feed dogs – teethlike metal grips that move under
the material and the presser foot that holds the material down. This is fine
for light cloth materials but for banners it produces little stitches which are basically a perforation of the material and
a weak point in the banner.
A more appropriate choice for banners is a dual
feed (unison feed) commercial machine better known as a “walking foot machine.”
On these machines the presser foot which sits on top of the material has its own set of gripping teeth and “walks”
in unison with the bottom feed dogs to create a double feeding action of the material.
This gives larger consistent stitches and more speed and pulling power for banner sewing. These machines also have both forward and reverse direction and are capable of turning a corner and going
all the way around the banner.
These walking foot machines are typically used
by upholsterers and can accommodate a wide range of fabric thicknesses. These
are extremely durable, lockstitch machines which means they employ a thread feeding through the top of the machines which
is locked by a bobbin thread feeding from the bottom of the machine. This forms a very strong stitch that does not unravel
easily – even when cut. There are also double needle lockstitch machines
which sound like the solution to creating a double row of stitches but they have drawbacks for banner sewing. These machines are larger, more expensive and more difficult to learn how to operate than a single needle
lockstitch. They typically have a 1/4" needle gauge which means setting the grommet will
cut through the stitches. Further, learning on this machine is far more difficult that learning on a single
needle lockstitch. There are two bobbins from below and two thread feads from above and trust me - this is tricky
at first. With the double needle lockstitch the operater can not go around
corners and has to sew off the edge of the banner four times to complete it.
It may sound time consuming to sew a second
row of stitches with the single needle machine, but that second stitch line goes very fast because the hem is already formed.
Despite owning double needle lockstitch machines we still prefer to use a single needle for most banners.
The other type of commercial machine used by
banner producers is the double needle chainstitch machine. This uses four spools
of thread feeding from the top of the machine. It does not require changing the
bottom bobbin thread which is partly why it’s the choice of large volume banner producers. These are high speed machines that were developed for the garment industry to sew double rows of stitches
like those on the leg seams and waist of pants and blue jeans. Because there
is no bobbin changing they can produce a great deal of work. They employ a pulling
wheel in front of the presser foot to pull the fabric through the needles. Because
of the puller and the mechanics of forming a chain stitch they only sew in a forward direction and cannot be reversed to “lock
off” the stitches. Like the double needle lockstitch they cannot sew around
the corners of a banner and have to sew off all four edges of the banner. Because there are no bobbins to deal with
these are much easier to operate when sewing banners than a double needle lockstitch.
Without reverse a chainstitch machine cannot
“lock off” a stitch to prevent unraveling by reversing over previously sewn stitches. This can be remedied somewhat by placing grommets in the four corners to lock the stitches. Some companies use lockstitch machines to sew off the two short ends of a banner. This is probably starting
to sound confusing if you have no sewing background. Remember – any of
these questions can be easily answered by telephone.
