Jackknife Traditional Quilt Block Free Tutorial

Posted by Elaine Huff on

Let's look at this traditional quilt block called Jackknife (also known as Treasure Chest, and Night and Noon). I was perplexed about doing the strips sets for the corner units and getting the strips the right width so they would work in the block. So here's my method (no bias edges) for constructing the Jackknife! Let's get started!

jackknife quilt block

Fabric Requirements for a 12" Finished Jackknife Quilt Block:

  • Light/Cream: 2 - 5.5" squares, and 2 - 5" squares
  • Dark 1/Red: 1 - 5.5" square, 1 - 4.5" square, and 8 - 2.5" squares
  • Dark 2/Black: 1 - 5.5" square, and 2 - 5" squares

jackknife fabric requirements

Sewing Directions:

Hourglass Units:

Step 1:

Using the two Light/Cream 5.5" squares, the Dark 1/Red 5.5" square, and the Dark 2/Black 5.5" square, sew together 4 three-color Hourglass units. You can find my tutorial for sewing an Hourglass block at https://fabric406.com/blogs/fabric406-blog/how-to-sew-a-basic-hourglass-or-quarter-square-triangle-block. Since the three-color version is a bit different, I'll run through the extra steps here. 

First you need to mark a diagonal line from corner to corner on the back of the Light/Cream 5.5" squares (as shown in the picture below). Then match one of the Light/Cream 5.5" squares with the Dark 1/Red 5.5" square and the other with the Dark 2/Black 5.5" square, right sides together.

jackknife 1

Step 2:

Sew a scant 1/4" on both sides of the drawn diagonal line and then cut on the drawn line to create 4 Half Square Triangle units as shown in the picture below. Open up and press the seam allowance away from the Light/Cream fabric.

jackknife 2

Step 3:

Using the picture below as a reference, now you can match up one of the Cream/Red Half Square Triangle units with one of the Cream/Black Half Square Triangle units, making sure the colors are opposing each other. Mark a diagonal line perpendicular to the seam allowance and sew a scant 1/4" on both sides of the drawn line. Cut on the drawn line. 

jackknife 2

Step 4:

Open up the Step 3 units and press the seam allowances. I've pressed my units using the tweak/twirl/furl method as you can see below. Square up/trim the units to 4.5" square.

jackknife 4

Corner Units:

Step 5:

Using the Light/Cream 5" squares and the Dark 2/Black 5" squares, make four Half Square Triangle units as shown in the picture below. Square up/trim the units to 4.5" square. You can find my tutorial for making a Half Square Triangle block at https://fabric406.com/blogs/fabric406-blog/how-to-sew-a-basic-half-square-triangle-block

jackknife 5

Step 6:

Draw a diagonal line from corner to corner on the back of the eight Dark 1/Red 2.5" squares as shown in the picture below.

jackknife 6

Step 7:

So here's the step I figured out to make it look like you used a strip set to make the unit. Now you simply snowball two of the corners of the Half Square Triangle units. Place a Dark 1/Red 2.5" square on the black corner of the Step 5 unit and sew on the diagonal line and repeat on the cream corner as shown in upper left unit in the picture below. 

Match up the corners of the Dark 1/Red 2.5" squares and press (upper right unit).

Unfold the Dark 1/Red 2.5" squares and trim away the the seam allowance (lower left unit).

Refold the Dark 1/Red 2.5" squares and your Corner unit is complete! (lower right unit)

Repeat for a total of four Corner units.

jackknife 7

Putting It All Together:

Step 8:

Lay out the Hourglass units, the Corner units, and the Dark 1/Red 4.5" square as shown in the picture below. At this point, I realized I needed to press the seam allowances on the upper left and lower right Corner units opposite of what is normal. So on those two units, press the seam allowances toward the inside of the block. This will help to nest seams so you get a good point - both in the block and when joining blocks together.

jackknife 8

Step 9:

Now the Jackknife quilt block goes together just like a basic Nine Patch block. Sew the units together into three rows as shown in the picture below.

jackknife 9

Step 10:

Press the seam allowances away from the Hourglass units as shown in the picture below.

jackknife 10

Step 11:

Sew the three rows together and you're done! Except . . .

jackknife

Step 12:

for the pressing. Press the seam allowances toward the center of the Jackknife quilt block as shown in the picture below.

jackknife 12

Conclusion:

I really enjoyed sewing the Jackknife quilt block together! I like how I did the Corner units so the edges aren't on the bias and there really wasn't much waste. Everything nested well and I got nice points! (That's always a win!) Plus, when put into a quilt, this block makes a wonderful secondary design - that will be my next blog post!

I hope you've enjoyed the Jackknife Quilt Block tutorial!

Happy Quilting!

Elaine

P.S. If you like these fabrics, they are from various Kim Diehl collections (I have a rather large stash of her fabrics). You can find her current fabrics at https://fabric406.com/collections/all/designer_kim-diehl

P.P.S. If you liked this post and want more quilting tutorials like this, simply click here and also receive a free PDF quilt pattern.


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  • I love this block colours and all .

    Joanne Thomas on

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