Monday, January 16, 2017

Quilt from a Simple Block



























In my last post I used a simple block to design this quilt top. My wife wants to make the quilt and asked me to produce a pattern for her. I thought I would work it out online and show you how I go about turning a promising design into an pattern.




First I need to decide how to piece it.

One traditional way to piece a quilt is to sew the blocks in rows and then sew the rows together.




















I don't like this. It means breaking the background into a lot of small pieces then sewing them together again. It would also be hard to keep track of what goes where in which row. The possibility for making mistakes is too great.

Six of the original simple block go together to make a larger unit that looks like an S. I would like to assemble the S units first and then piece the quilt top.




















I like this. There is a lot less sewing. It's easier to keep track of what goes where. The quilt top can be divided into four quarters that can be sewn separately and then joined together.










Each quarter contains four S units and three different sizes of background pieces.



The piecing for this is obvious and easy. Three A's get sewn to three S units. Then those three get sewn together and a B added. An S unit and a C get sewn together and then joined to the  ABS combination.
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Now seems like a good time to start calculating how much back ground fabric I need.

The A pieces are 4.5" x 9" finished size, which means they have to be cut 5" x 9.5". There are 3 per quarter, which means there are 12 in total. I can cut them from a piece of fabric that is 5" x 9.5" x 12, in other words 5" x 114".

The B pieces are 4.5" x 18" finished, which means they have to be cut 5" x 18.5". There are four of them in total. I can cut them from a piece of fabric that is 5" x 74".

If I add my A's and B's together, I find I need a piece of fabric 5" x 188". That's all well and good, but I can't buy a piece of fabric that size. Fabric comes 40" wide and some times a little wider. If I divide 188 by 40 I  get 4.7, which rounds up to 5. I need 5 strips of fabric 5" wide and 40 " long to make the A and B pieces. In other words I need a piece of fabric 25" x 40".

There are four C pieces that are 13.5" x 22.5" finished, which means they have to be cut 14" x 23".

I can cut them from a piece of fabric 42" x 40 ".

If I add this to the fabric for my A and B pieces, I find I need a piece of background fabric 67" x 40". I will add in the background fabric for the S units and borders later.





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The S units are made from six blocks. There are two each of three different blocks.

The three blocks are identical in construction. They are just colored differently.










Each block is 4.5" x 4.5" finished size and is made from three strips. Each strip is 1.5" x 4.5" finished, which means each strip is cut 2" x 5".

The triangles on the ends of the strips are made using the connector corner method. A 2" x 2"  square is placed right side down on the end, sewn on the diagonal and folded back to make the triangle. The back is then trimmed to leave a 1/4" seam allowance.
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It's time to calculate fabric quantities for the S units. I'll start with the background fabric.

There are 16 S units in total (four in each quarter). Each S unit is made from 6 blocks, so there are 16 x 6 = 96 blocks. Each block includes a background strip 2" x 5". I can cut these from a strip of fabric 2" x 5" x 96, in other words 2" x 480".

Four of the blocks in each  S unit have two corner triangles of background fabric. That makes 16 x 4 x 2 = 128 corner triangles These start as 2" x 2" squares. I can cut the squares from a strip of fabric 2" x 2" x 128, in other words 2" x 256".

The total amount of background fabric for the S units is 2" x (480" + 256"), in other words 2" x 736". When I divide 736 by 40 I get 18.4 which rounds up to 19.  I need 19 strips 2" wide by 40" long, which means I need a piece of fabric  38" x 40 ". I calculated earlier that I need a piece of background fabric  67" x 40". When I add the two together I get 105" x 40".
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Next I'll calculate the black fabric.

All the blocks in the S units have a 2" x 5" black strip. That means 16 x 6 = 96 black strips. These can be cut from a strip 2" x 5" x 96, that is to say 2" x 480".

All the blocks in the S units have two 2" x 2" black triangles. These can be cut from a strip 2" x 2" x 2 x 96, that is to say 2" x 384"

In total for the S units I need a strip of black fabric 2" x (480" + 384"), more commonly known as 2" x 864". When I divide 864 by 40 I get  21.6 which rounds up to 22. I need 22 strips 2" x 40" which means I need a piece of fabric 44" x 40".
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Next comes the dark blue fabric.

Four of the blocks in each S unit have a 2" x 5" strip of dark blue, making 64 strips in total. These can be cut from a strip 2" x 5" x 64, or rather 2" x 320"

Two of the blocks in each S unit have 2 triangles each, making 64 triangles in total. These can be cut from a strip 2" x 2" x 64, call it 2" x 128".

When I total the strips of  dark blue fabric I get a strip 2" x (320" + 128"), or 2" x 448".  When I divide 448 by 40 I get 11.2 which rounds up to 12. I need 12 strips of fabric 2" x 40", or rather a piece of fabric 24" x 40".
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It's time to do the light blue fabric.

Two of the blocks in the S units have a strip of light blue 2" x 5". That's 32 strips in total. These can be cut from a strip 2" x 5" x32, which is a strip 2" x 160". When I divide 160 by 40 I get 4. I need four strips 2" x 40 " which I can get from a piece of fabric 8" x 40"
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When I assemble all the pieces so far, I get a square top 63" x 63". Now I need to consider what to do about borders.


My wife wants to hang this quilt. In the place where it will  hang there is only room for a quilt 6'-3" wide. To be safe I'll make it 6ft (72")wide. That only leaves me 9" of width for borders, which works out to 4.5 " per side.

I can get 4.5" with a 2.5" background strip, then a 1/2" accent strip, then a 1.5" background strip, and finally a 1/2" binding strip.( 2.5 + .5 + 1 .5 = 4.5) The binding strip isn't in the calculation because it goes over the second background strip.

On two sides the first background strips need to be 2.5" x 63" finished size. So they need to be cut 3" x 63.5". The back ground strips on the other two sides need to match the quilt top and the first two strips so they are longer, 2.5" x 68" finished size. So they need to be cut 3" x 68.5"

When the time comes to cut these pieces they will obviously need to be cut along the length of the fabric. However, for the purpose of calculating how much fabric I need I am going to pretend they come from strips 40" long. For the back ground strips I will need a strip of fabric 3" x (63.5" x 2 + 68.5" x 2). This is a strip 3" x 264". When I divide 264 by 40 I get 6.6, so I need 7 pieces of fabric 3" x 40", or one piece of fabric 21" x 40".

When I add this to my previously calculated 105" x 40" of background fabric I get 126" x 40".

The quilt top is now 68" x 68".
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I've decided to make the accent strip dark blue and the binding black. On two sides the accent strips are 1/2" x 68" finished size. They need to be cut 1" x 68.5". On the other two sides they will be 1/2" x 69". They need to be cut 1" x 69.5".

For the accent I need a strip of dark blue 1" x (68.5" x 3 + 69.5" x2). This is a strip 1" x 276". When I divide 276 by 40 I get 6.9, so I need 7 strips 1" x 40" which is a piece of fabric 7" x 40".

Previously I calculated I  needed a piece of dark blue fabric 24" x 40". When I add the pieces together I get a new piece 31" x 40".

The quilt top is now 69" x 69"
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I need to add in the last of the background fabric. On two sides the pieces are 1.5" by 69" finished size. They need to be cut 2" x 69.5". The other two sides are 1.5" x 72" finished. they need to be cut 2" x 72.5".

I need a strip of background fabric 2" x (69.5" x 2 + 72.5" x 2). So I need a strip 2" x 284". When I divide 284 by 40 I get 7.1 which means I need 8 strips 2" x 40" or a piece of fabric 16" x 40".

By my last calculation I needed 126" x 40 " of background fabric. If I add in this new piece I get 142" x 40"

The quilt top is now 72" x 72".
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Linda likes to do double fold binding, so the binding strips need to be 2.5" wide. I need four strips 2.5" x 72". This is equal to one strip 2.5" x 288". Divide 288 by 40 and I get 7.2. I need eight strips of black fabric 2.5" x 40 " or a piece of fabric 20" x 40".

Previously I came up with 44" x 40" of black fabric. My new total is now 64" x 40".

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So far I've calculated the absolute minimum amount of fabric needed to make the quilt top. This amount of fabric will work only if a miracle happens. First, there is no waste and every square inch of fabric is used. This not going to happen. Second, no mistakes are made. This can happen but never does when I sew. Now I've got to decide what would be a reasonable amount of fabric to buy.

First, the background fabric. I calculated 142" x 40". Which works out to be 3.95 yards. I would go with 4.75 to 5 yards.

Second, the black fabric. I calculated 64" x 40". This works out to 1.8 yards. I would go with 2.5 yards

Third, the dark blue fabric. I calculated 31" x 40". This is .9 yards. I would go with 1.5 yards.

Fourth the light blue fabric. I calculated 8" x 40". This is .25 yards. I would go with 1/2 yard.

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What do I need to cut?

Background Fabric
2 strips 2" x 72.5"
2 strips 2" x 69.5"
2 strips 3" x 68.5"
2 strips 3" x 63.5"
4 pieces 14" x 23"
4 pieces 5" x 18.5"
12 pieces 5" x 9.5"
96 pieces 2" x 5"
128 pieces 2" x 2"

Black Fabric
I calculated the binding strip as 4 pieces 72" long, but Linda makes one long binding strip. I need to allow  for piecing the strip and turning corners.
1 piece 2.5" x 320"
96 pieces 2" x 5"
192 pieces  2" x 2"

Dark Blue Fabric
2 strips 1" x 69.5"
2 strips 1" x 68.5"
64 pieces 2" x 5"
64 pieces 2" x 2"

Light Blue Fabric
32 pieces 2" x 5"

When it comes to cutting the fabric cut the largest pieces first and allow for the fact that they may need to be bit larger depending on what happens when the smaller pieces are sewn together.

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Conclusion:
It is a lot easier ans faster to design a quilt top than it is to work out how to sew it and calculate fabric.

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