Diagonal Pieced Back Calculator
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The Story of the Diagonal Pieced Back or John’s formula for Joan’s Trick
John’s sister Joan, called him one day because she had a piece of fabric which wasn’t quite long enough to cut in half and sew back together with a vertical seam to get a quilt back. Her idea was to cut the fabric in to two big triangles along the diagonal, offset the triangles along the diagonal cut to get the width she needed and then sew them back together. It worked great!
There is a mathematical formula involved, and that’s where John came in. Try the example and study the diagrams and images. This is a cool trick to know.
Here is why we like to use diagonal seams for making our quilt backs. First of all, it saves fabric! Then, instead of having a straight seam with the bulk of the seam allowance all in the same spot as everything rolls up, the seam allowance rolls up diagonally along the back and isn’t in the same spot every time. Sometimes, with a really busy print, a diagonal back seam will be almost invisible.
Before Joan came up with her trick, John sometimes just cut his back fabric diagonally and sewed in a wide contrasting strip to make the back wide enough. That’s one solution.
John’s method for diagonally piecing a quilt back, from one piece of fabric, is the most efficient way to make the back when the width of the quilt back is 1 ½ times, or less, than the width of the fabric you plan to use. For example, if the width of your back fabric is 44”, use John’s method whenever the width you want your back to be is 66” or less. If you are using fabric that is 60” wide, use John’s method whenever you want your quilt back to be 90” or less.
John has calculated a simple formula to figure the yardage for you to figure how much back fabric you need. Work through this example to become familiar with the formula and you will be able to figure the yardage for the diagonally seamed back of any quilt.
Ready? Here is the formula for example
Example 1 Quilt Top measure 48” x 60”.
For this example, assume you want your quilt back to be 51” x 66”. The desired length of the back goes in to the formula as LQ=66. The desired back width goes in to the formula as WQ=51.
For the example, the width of the fabric is 44”. This goes in to the formula as wf=44.
Solving for LF (yardage required)
Or (462 divided by 37) or 12.5 +66. For the length of the back you will need 12.5 inches + 66 inches which equals 78.5 inches – let’s just say 79”!
For back wider than 1 ½ of your back fabric’s width, you will need two lengths of fabric 6” longer than the length of your quilt. At these sizes, the trick doesn’t save you fabric but does make quilting easier because of the diagonal seam.
Stack the two lengths of fabric one on top of the other, both face up. Cut a long diagonal slice off the side of the stack through both layers. Rotate the top fabric 180 degrees and sew the two big pieces together with a ½” seam. Press the seam open. Click here for Visual Instructions
Here’s to nicer quilt backs!
STORM AT SEA QUILTING EXAMPLE
Quilters often admire the way John quilts his Storm at Sea class samples. He has done dozens by now and the straight line quilting really does set off the curved illusion that you get with the Storm at Sea block.
You can download it here Quilting Example
Our friends at Superior Threads have a great article on Top Thread Tension, often a problem when machine quilting. I learned a lot and hope this is useful to you. Thank you to Bob and Heather Purcell of Superior Threads!
STORM AT SEA CHART
For now, most of our laser pre-cut kits are wall hanging or lap quilt size. But quilters like to make bed quilts, so Kate figured out how many 16" Storm at Sea Kits it would take for a twin size and a queen size project.
The answer: 2 16" Storm at Sea pre-cut kits make a 52" x 76" project and 3 of the 16" kits make a queen size project 64" x 88". Here are a couple of placement diagrams. Hope this helps!
Aren’t Rag Quilts fun? They are quick colorful and practical. Our family thinks they are great for gifts.
We make rag quilts a little differently. Instead of making little packages of backing top and batt, we use pre-quilted fabric. We cut it up in to the different size squares and sew them together. Because there is batt in the edges of the squares, just washing the rag quilt in the washer doesn’t make if fluff up, though. John’s solution is the Weed Whacker Quilt. To fluff up those edges, he tacks the clipped quilt down to a sheet of plywood, or sometimes, just tapes it to the concrete floor and whacks the edges with an electric weed eater. The fluff really flies then!
Start with four 36” x 44” pre-quilted panels, two of each color makes a nice quilt. We have lots of quilted demo quilts left over from demonstrating the Multi-Frame at quilt shows. You can use pre-quilted fabric or make your own on the Multi-Frame.
Cut one of each color of the 36” x 44” quilted pieces into six 11” squares and fifteen 6 ½” squares.
The other two quilted panels are cut into three 11” squares and twenty 6 ½” squares.
Sew the 6 ½” squares together in four patches, alternating the colors.
Use a 1” seam allowance. John often uses a piece of moleskin 1” from the needle for a seam guide.
Four 36” x 44” pre-quilted pieces make a rag quilt about 45” x 63”. Stay stitch an inch in from the edge all around the quilt, sewing the seam allowances down all in the same direction. All the raw edges need to be clipped.
The easiest way to clip is with a pair of spring loaded craft shears like Fiskars brand. Clip to within 1/8” of the stay stitching and ¼” apart.
After all the seams have been clipped, it is time to whack. You can tack the quilt down to a sheet of plywood or tape it to a clean concrete surface. Unless you have a big open work area, you will want to do this outside.
Use an electric “Weed Eater”, not the more powerful gasoline model. Just angle the head of the tool so the plastic cord whips the quilt’s edges to fray them. You can see how well you are doing as you go. Keep after the edges until they are all fluffy.
Wash the finished quilt and dry in the dryer. Just what the doctor ordered; a warm fluffy, colorful quilt to see you through the winter. Whack away!
Pressed patchwork seams really affect how the quilt looks on the wall or on the bed. Nice, flat patchwork is easier to quilt too. John and Kate press as they piece with an ironing area right next to the machine. Planning which direction to press long seams so the four patch intersections can be pressed open like the example helps your patchwork stay flat.
Using “Sew Fine” by Superior Threads helps.
If you want a small supply of John’s business cards which have a guide for the “scant quarter inch” printed on the back, just send us a self=addressed stamped envelope and a note with your request.
Things change and we don’t sell the popular Cut-Your-Own Template Kits anymore. If you have taken a class from Sharyn Craig, or have one of her books, you know she likes plastic laminate templates, especially for one of a kind blocks.
The reason we can’t sell the the Cut-Your-Own Template Kits anymore is related to change too! Something in the way the laminate material is manufactured has changed and we can’t depend on it being flat enough in the big 4’x8’ sheets we use to cut efficiently. For economics sake, we have to be able to use 100% of the material without any waste. So things have changed with the manufacturers, and we had to change too.
But, if you still want to make your own templates, here is what to do. You need a good pair of utility shears. Then, look in the Yellow Pages to find a cabinet maker’s shop. They should have scraps of plastic laminate they are willing to sell you. Brand names don’t matter; what you want to ask for is “vertical grade laminate” or “post-forming laminate”. These are similar to, but thinner than, what we all used to have on our kitchen/bath counter tops until granite got so popular! You need the thinner grade so you can cut it with your shears.
To cut a template shape, draw a cutting line, and make a rough cut around it with the shears. Don’t close the shears all the way until you are to the end of the cut. After you have a piece roughly cut out, do the final cut on your pencil line. Cut slowly and let the template gently bend up over your hand if it is large. The ware will just fall away as you work, and remember not to close the shears all the way as you cut.
Double check the accuracy of your template with your original draft and, if it is little big here and there, you can take a file and file the excess off. You have a couple of options for coating the back to make the templates a little sticky. Apply a very thin coast of rubber cement and let dry or some quilters use 500 Spray and Fix or similar adhesive. Double Stick tape also works as does Steam-A-Seam 2.