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Wednesday, June 01, 2005

That Quarter Inch!

That Quarter Inch!
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Sometimes it is difficult to get that perfect seam while piecing. Here are a couple tricks! What you want is really a "scant" quarter of an inch,but before you get that, you need to know exactly where a 1/4" is on your machine. Many presser foots say they are a 1/4" foot,but if you can see the fabric peeking out from the side of the foot, chances are your seam allowance is bigger than it needs to be and your units won't fit together when you go to sew the parts into blocks.

Here's a little test for you!



Above are two index cards....hard to see the lines,I know, but they are there! On the second card I have trimmed on one of the lines. Most index cards have lines that are exactly 1/4" apart! It is a good idea to check them with your ruler to be sure.



Take the card to your machine and put the needle down through the card on o ne of the lines. This is where it does get suprising...I hope you can see it...1/4" with my bernina foot is actually UNDER the edge of the foot. If I go to the edge of the foot, using it as my guide, my seams are going to be just a smidge too wide!


You can find "mole skin" in the pharmacy. It is used for bunions and corns as padding in the shoe for callouses, etc. Cut a 1/2" strip of mole skin and peel the backing off of it. Position it up next to your card in FRONT of the feed dogs. Make sure that nothing is covering or interfering with the feed dogs. Now for the rest of the test! Turn the card OVER so you don't see lines. Stich through the card using that 1/4" seam you just set.



Turn the card over, and Voila! Your stitching should be EXACTLY on the line! If it is not, adjust the placement of the mole skin until you get it right. Replace the mole skin when the edge seems to get worn or thready. You can also use several layers of masking tape, or foam core...anything you can find to build up that little "fence" to run your fabric against to keep your seam allowances consistant.

  • Here′s a test to find out if you′re really achieving that perfect quarter inch seam allowance:

  1. Cut (3) 1.5" X 3.5" inch strips.
  2. Sew them together lengthwise.
  3. Press the strip set carefully.
  4. Measure the center strip. It should measure 1 inch EXACTLY! The whole unit should measure 3.5" square.
  • The perfect seam allowance is actually a SCANT quarter inch. This is due mostly to the fold of the cloth over the seam allowances. Thicker piecing thread can give you a thicker "fold over" allowance when pressing. To get the "scant" part, actually sew a couple threads narrower than a true quarter inch if needed.

  • The general rule is to never sew over an unpressed seam. However, during block construction there is a danger of distorting the bias if seams aren′t carefully pressed. You may find finger-pressing faster and safer than conventional pressing. Just turn the seam in the proper direction, and use the heat of your fingers to press the seam. Just the part of the seam you are about to sew over needs to be pressed, not the entire seam. Be gentle and do not pull or distort the fabric. Pin and sew the next section of the block. After the block is completed, or at least after a section has been completed with no bias sections on the outside, press with an iron in the conventional manner.

  • Sometimes it is necessary to pin before sewing patchwork. Do yourself a favor and use pins with a thin shank. Thick pins will only be a nuisance and will many times shift the seam.


4 comments:

Anonymous said...

Bonnie:
Just know somewhere on your blog you have to have info a where or not you use Srapy Startst/Sizing!
The other day while making string blocks, it hit me...since I don't paper piece mine, should I then spray starch them for better control on blocks cut on the bias?
Your info and help really would mean alot.
THANKS
JulieinTN

Bina said...

Awesome tip! Thank you so much. I'm going to do this!

jenni said...

Genius! Thank you!

Danese Ballantine said...

From Danese - Hey! Bonnie - met you in Williamsburg at Quiltmaker Retreat. You had a small ruler with a needle hole and 1/4" marked along with other measurements. I really would like to get about 5 more of these rulers. I don't see them on your site. Can you tell me best way to get some of these rulers?
Thanks so much - Danese