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Half Square Triangle (HST) Queen Size Quilt - Pinning, Sewing, Cutting

How was everyone's weekend?  Ours was busy as usual.  The step-son came over to pick up his dog.  It was bittersweet, the dog really was too big for our lifestyle but I had started to grow awfully fond of him.  The boxer dog and little cat though are happy to see the big black lab mix go.  He was just a couple years old, full of energy, and not a clue that he was so much bigger than everything else. lol  I spent my free time this week getting blocks ready for today's tutorial.  Lots of pinning, sewing, and cutting, and pressing for this project.  The nice thing though it's just the same thing over and over so not a lot to remember.  Ready to get started?

HST pinning, sewing, cutting directions

Before we get started I want to give you a little more information on the way we are doing our HSTs.  There are numerous ways out there to make half square triangles.  We actually are going to make 8 blocks at once.  Now I gave you the sizes for our project but if you ever want to make them again there is a simple math formula you can use.  The other great thing about this method is they come out a little big so we have a little fudge room.

Math Formula: Finished Size (what do you want to end up with) + 7/8" Multiply that by 2.  Example: 5" + 7/8" = 5 7/8", 5 7/8"x2 = 11 3/4"  So to finish with 5" squares you need to start with 11 3/4" blocks.  7/8 as a decimal is .875 so you can use a calculator to do your math. :)

The first thing we have to do is pin our blocks together.  We don't want the fabric shifting while we sew.  If I say pin you really need to pin, I don't pin unless it's absolutely necessary.  Don't panic you don't have to do them all at once.  I didn't have enough pins to do them all at once.  I worked in batches of 10.  Pin in the middle of the triangles that formed from the X that you drew.  This way you don't have to stop when sewing.  When I got half of them pinned I started sewing.  Doing them in batches also lets you see that you are making progress.

Now we sew!!  The Xs that we drew on our white blocks are our sewing lines.  We sew 1/4" from the line on both sides.  I chain sew these, 10 at a time.  Down one side, up the other, then I clip the threads holding them together, and repeat those steps with the other line.

A 1/4" foot is a must for this.  Keep the edge of your foot right next to the line you drew.

Just keep adding the next block when you get to the end.

Ahh the chain!!

The last block of the chain, becomes your first one when you sew
down the second side of the line.

Keep your blocks going the right direction.  They like to twist.

Clip the little threads holding the blocks together.  If you have kids
this is a great job for them.  I don't know how many chains I cut apart
when I was a kid.
That wasn't too bad was it?  Now we cut!  This is where the magic happens.  We are going to end up with 8 half square triangles for every block we sewed.  Before you cut make sure that there's no goofs on the backside of your square.  You want to fix the errors before you cut.  Cutting is where the rotating mat comes in handy.  You'll never have to touch the fabric, just move the mat.

Start by cutting on the lines we drew.

Now we are going to cut it in half top to bottom and left to right.

You can see the 8 squares we made.
Now we have to press them open.  Press the seam to the plaid.  We don't want shadows on the white fabric.  Don't panic when they look funny.  We'll trim them up in just a second.

Eww that's an ugly block.
Remember that ruler I told you about with the diagonal line down it?  This is where it becomes a life saver.  This is also where you can trim out little errors since our blocks are oversized.

Keep that diagonal line straight with your fabric.  I line up on the 3 1/8" line for this side and trim. 
Rotate a half turn and this time line up on the 3" line.  Trim away the extra.
That's it!  You've got a pretty HST now.

So much better than before.
Just keep repeating until you have them all done.  I know it's daunting but I'm doing it right along with you.  Next week we'll lay all those blocks out and start sewing our quilt together.

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Would you like to comment?

  1. Oh my goodness! Sewing and math together? Yikes, I would need a tutor for the math and a mechanic to help me constantly untangle my machine. All kidding aside, you have put together an excellent tutorial. I think even I could handle one least! ;-)

    1. Quilting has lots of math sadly. lol I married a mechanic, granted he's used to huge commercial refrigeration units but he keeps my sewing machines going. Anyone can handle one square. ;)