early on in my quilting life a teacher taught us this method
for 1/4" accuracy.--cut 3 fabric strips that are 1 1/2" by
4 1/2. sew these together lengthwise. gently press. they
should measure 3 1/2" across. if less than that,your seam is
too big--if more than that, your seam is too small. Adjust your seam (by sewing more strips) whichever way you need to, measure again. do it for each machine you use if swapping back & forth to finish a project. what foot you use, thread, does not matter as long as that strip is 3 1/2" wide. this
shows the seam in the fabric better than rulers, etc.

Therefore, some rules (if I can use that term) Always calibrate or adjust your seam allowance before beginning the sewing and make a test piece to be sure and then USE THE SAME machine for the entire project and never assume the measurement will continue throughout the projejct. For accurate work it is necessary to check and correct as the project goes along.

Holice, this is great...we should all do this BEFORE even starting to sew as frequently it is not possible to start and finish a project on the same machine. Alot of us have different machines that we use; one at home, the smaller one we bring to class, and in my case, a totally different machine that I have at my daughter's house for using while I'm there for a month once or twice a year. This is a great thing to do before sewing each time, making sure your seam allowance is the same, no matter which machine. I think the easiest way to do this is to sew 2 squares together with a seam that is exactly 1/4" (or scant) and keep it and try it BEFORE sewing on any machine. That way you know at once...just put it under your machine foot, hand lower the needle, and move needle for adjustment...and you can do it the very first time you try! Should work on any machine! I'm off to my daughter's on Wed. for a month and will definately do it, cuz I plan to work on some BOM's I have to catch up on and will still need to work on for a few months when I get back here. I tried that once without checking to see it was exact and suffered the consequences when I tried to get it all put together 2 years later as a UFO...took me alot of work to make it look nice!

Here's another way to test using these three strips: I use a lighter strip for the center, then press the seams away from the center strip. If the center strip measures exactly one inch after pressing, your seam allowance is perfect. If not, adjust the seam allowance by one thread-width at a time until it measures exactly one inch.

Thank you! I am going to test my quarter inch foot now.

Since I don't see very well, my husband attacked a guide to my machine. He set it at precisely 1/4" from the needle in position 1. I like to make my exchanging squares about 13" so the receiver can trim to match what they need. I do this because I can't really see all the lines on my ruler accurately, but now I have a more technical excuse :wink: Gwyn

:shock: that's amazing such a difference between the two pieces...I'm glad I'm only sewing on my own machine.

I never would have guessed this could be true. thanks for sharing.

So I guess the best rule would be to stick with the machine, foot, etc. you start with and don't use a different machine in mid-project.

That was a great visual, and thank you for sharing. I do all my piecing on my Singer 221, which does a nice 1/4" seam, and am trying to learn FMQ on a newer Brother. I agree with the person who said, "Give me a vintage machine anytime!" I know that at anytime I can open them up and figure out what's going on and get them going again.

Oh crap! I had NO idea this could happen. I was doing the same thing to save myself from packing up my machine every week, but NO more...

At home I sew on a Husqvarna, at class I was sewing on a Janome and didn't see the difference, but then I had calibrated both machines. I am NOT taking any more chances!

A hint a friend just told me this week is, if you can move your needle move it once to the right. Sew a seam and measure to see if it comes out that scant 1/4". I tried it and it worked for me.