Diagonal Seamed Quilt Back – The John Flynn Method

I’ve been making some quilt backs for Jacquie’s (Tall Grass Prairie Studio) Project Improv.

It provided the opportunity to try out a quilt back piecing method I’ve had bookmarked for a long time: The John Flynn Method of a Diagonal Seamed Back (page down to the bottom of that page where he has step-by-step photos and a printable set of instructions).

This method is intended to make optimal use of your fabric thereby minimizing the yardage needed. The backing fabric is cut on the diagonal, the two pieces are adjusted (basically you slide one side down) and then sewn back together. My first experiment came up short on that claim. One of two things most likely happened:

  1. I didn’t do it correctly (high probability this was the problem!).
  2. The results may vary depending on what size quilt back you’re attempting to create.

My target quilt back size was 56″ x 68″. I plugged this into John’s formula and came up with: LF = 68 + (( 68 x (57-42)) divided by (2 x 42) – 57). Don’t let the equation scare you! It’s very easy to plug the numbers in. The result of that is 106″ or 2 yards and 34″ of fabric. I rounded up and used a 3 yard cut.


1. Step 1, 2. Step 2 – Top View, 3. Step 2 – Side View, 4. Step 3, 5. Step 4 – Overview, 6. Step 4 – Close Up, 7. Step 5 – Double Checking It’s Wide Enough!, 8. Step 5, 9. Step 7 – Diagonal Seam Just to the Right of the Black Line

I debated on how to discuss this technique in a blog post. I’ll tell you, it’s very confusing the first time you do it. The best way to understand it is to go through the process yourself. I’m linking to the pictures I took as a resource if you do give it a try.

In a nutshell:

  • Fold the entire 3 yard length of fabric on the diagonal
  • Fold it on top of itself several times
  • Cut the folded edges off (this is very similar to creating bias strips from a folded piece of cloth)
  • Carefully pin the diagonal edges back together (offset enough to create the width you need)
  • Sew the diagonal seam

Final Results: my quilt back was short an inch on the length. I rounded up at every opportunity during the calculation. Again, user error is most likely the culprit which leads me to my ultimate opinion on this method of piecing a back: it’s awfully darn fussy for the results I got and the amount of time it took to cut the fabric!

Besides trusting you did all the math correctly, it’s very nerve wracking to cut your fabric in half along a diagonal line of 4 layers of folds. The bias edge then becomes a delicate beast needing to be stroked and coddled until the seam is finally sewn.

An additional limitation is that this method is only appropriate for a non-directional fabric design because of the way the patterns are angled and sewn back together.

I think this would be a good tool to know in the event you have a fabric backing that you really want to use but there’s not enough fabric to make it work with traditional piecing. It would be worthwhile to run the math and see if a diagonal seam might just get you the backing size you want.

I pieced the remaining backs using two additional methods. I’ll explain those next week (and guess what, one of them used LESS than 3 yards of fabric!)

pink chalk fabrics ~*~ new arrivals ~*~ free patterns ~*~ on sale
pink chalk fabrics ~*~ new arrivals ~*~ free patterns ~*~ on sale
40 Responses to Diagonal Seamed Quilt Back – The John Flynn Method
  1. Des
    March 13, 2009 | 10:18 am

    Wow. I will need to read and re-read this and then practice and re-practice. but it sounds great. I detest sewing backings and using all of that fabirc!! This sounds interesting. Thanks for showing, Kathy.

  2. Sarah
    March 13, 2009 | 10:20 am

    wow thanks for the tip! I absolutely LOVE that fabirc. I just ordered some from you last week and I cant decide if I should make a blaket or some summer dresses for my girls or a skirt for myself.. I am so new to sewing so “quilting” is something I admire and hope to learn myself sometime soon but it also feels intimidating at the same time. But any tip that helps you not to need so much for the backing has got to be a good idea.

  3. Carrie
    March 13, 2009 | 10:57 am

    I’ve never heard of this unique method. Sounds a little complicated, but good for you for trying it out (and subsequently sharing your trials with us!)

  4. Stephanie
    March 13, 2009 | 11:07 am

    How very interesting. I would have never thought of diagonal backing. I love your fabrics…I’m a HUGH Denyse Schmidt fan.

  5. Alissa
    March 13, 2009 | 11:26 am

    So nice of you to be making backs for Jacquie!! And sounds like we’re all gonna learn a little something along the way! Can’t wait to hear about the other methods!

  6. Kristin L
    March 13, 2009 | 11:50 am

    I was aware of this method but hadn’t tried it out myself. Thanks for taking it on a test run for us! I’m looking forward to your two other methods, as I think all three will be a great resource.

    Kudos to you for supporting the Brushfire Project too. :-)

  7. Kristin L
    March 13, 2009 | 11:52 am

    Whoops, I meant Project Improv — they are both wonderful charity quilting projects that have grown so much more than their generous creators anticipated (and both are projects I’ve been following online, hence the confusion).

  8. Bridget
    March 13, 2009 | 12:11 pm

    This sounds a little like this http://pir8.freeservers.com/quilting/CBT/cbt-webpage.pdf way of making your own bias binding – again, trying to minimize the amount of fabric needed.

  9. wendy
    March 13, 2009 | 12:25 pm

    wow, like everything in life it comes down to whether you have more money or more time! This may fall under the small category of things for which I have more money.

  10. Michele C
    March 13, 2009 | 2:19 pm

    That looks so interesting! He must have been a math genius to have figured it all out in the first place.

  11. Candied Fabrics
    March 13, 2009 | 2:34 pm

    My 1st thought – boy, what a lot of fuss.
    My 2nd thought – seems like there’s a lot of chances to add ripples and waves and bubbles in the quilt back, which is hard enough to control already.
    My 3rd thought – Kathy, you’re brave. Thanks for doing this for us!

  12. Elaine/MuddlingThrough
    March 13, 2009 | 2:49 pm

    What a great idea! Thanks for sharing.

  13. Sherri
    March 13, 2009 | 8:40 pm

    This was really informative…I’ll look forward to seeing the method that took less than 3 yards!

  14. nicolette
    March 14, 2009 | 2:39 am

    Hi Kathy, I want to say thank you for all the backings you’ve made and send to Jacquie! You’re the best!!!!

    I have to reread this back-piecing method a few times, because I don’t quite get it..! Maybe I should practise with a small long strip of fabric…!?

  15. Brianna
    March 14, 2009 | 6:35 am

    GREAT fabrics!

  16. Jean C.
    March 14, 2009 | 10:15 am

    Hmmmm, I don’t think I’m up for that… the idea of cutting the folded edges off (thus in my mind wasteing fabric) doesn’t come easy to me! Think I will stick to my TNT methods… the fabric is great though!

  17. Addie
    March 14, 2009 | 3:52 pm

    I think it’s a brilliant way to be efficient with fabric! My mind is constantly trying to get the most from the fabric I have purchased. Thank you for the tip. I think I’ll start practicing.

  18. Fanny
    March 15, 2009 | 6:14 am

    So interestesting that you posted this – I just discovered John Flynn’s site yesterday (thinking about buying one of his quilting frames). All that math scares me! I may end up trying this….someday… All the opinions are invaluable. Thanks!

  19. sara's art house
    March 26, 2009 | 6:55 pm

    Gorgeous fabric!

  20. Heidi
    May 12, 2009 | 12:14 pm

    I use his method all the time! Some years ago I made up a little spreadsheet to plug the numbers into. I lost that one when I got a different computer, but found several on the web. I’ll try to find a link for you to try. (I’d upload the one I’m using now, but it’s on a Mac–which I’m still getting used to–and the filenames don’t come out right.)

    One caution: don’t forget to add the extra couple of inches to each side that you’ll need for quilting! Also, for some reason, it comes out different if you exchange the numbers for length and width, so to play it safe, I use the larger.

    There’s another benefit to the method if you’re quilting on a frame–the seam doesn’t pile up as you roll the quilt.

    –Heidi

  21. Sandi
    May 14, 2009 | 7:49 pm

    My biggest challenge is cutting the diagonal. I’m afraid I’ll cut it crooked, and it’s hard to handle that mass of fabric. I’ve used this method once, and I cut it far too close, too. However, the biggest advantage to this method is for frame quilters. When you roll a diagonally pieced backing on your frame, the seam doesn’t bunch up in one place, as a vertically pieced backing would. Instead, it is distributed evenly across the width of the quilt.

  22. Anja
    July 2, 2011 | 10:52 pm

    It is simple if you stop thinking too much about it. Just lie the fabric down at 45 degrees
    Measure across to the width you want and cut
    Then lie the selvage together for the two pieces and join
    Measure across and cut
    Repeat until you are happy

    The length of fabric you will need will be the final length you want divided by the measurement of the diagonal measurement of the fabric

    This is how many times you will need to sew and cut

    Add on one extra length for the filling in the first triangle left going the other way

    Don’t forget to allow for seam allowance each time

  23. Val Pankratz
    September 10, 2011 | 4:59 pm

    I’ve used this method a number of times and it’s amazing how it can save $$ on the amount of backing fabric. It sounds more complicated than it is, the diagram from Flynn helps to make sense. I’ve also found that if you have enough square footage to lay out your backing fabric on the floor, it’s sometimes easier to cut that way. I also had a quilter at a retreat who’s brilliant idea was to use a laser measuring tape to mark the line on the diagonal. She just put the tape on the floor on the bottom left corner of the fabric, turned on the laser till it lined up to the top right of the fabric and then there was her cutting line, no need to mark. IT was then easier to slide the triangles till the backing was the right width, then trim off the ends, pin and sew! Good luck!