May 12, 2015

Squaring Half-Square Triangles Tutorial {Without Specialty Rulers}

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Here's a method of squaring or trimming HSTs that doesn't require specialty rulers.  A rotating mat is very helpful but also not required.  You just need a cutting mat, rotary cutter, and a ruler.

Note:  This HST is being squared to 9.5" square.

Step 1:  Line up the diagonal line of the HST with the diagonal line on the cutting mat.  Place the bottom left corner near an inch line.  Make sure that there will be fabric to cut off of each side, remembering that the left and bottom sides will be cut on an inch line, and the top and right sides will be cut on the half-inch line (because the HSTs are 9.5").  Go back and make sure the diagonal line of the HST matches the diagonal line on the mat.  


Step 2:  Line up the ruler with the half-inch marks on the cutting mat and cut the right side.  Carefully pick up the ruler without moving the block.  Do not move the block, unless you don't have a rotating mat, in which case you'll rotate the block clockwise and line it up again.  If you do not have a rotating mat and are moving the block, be careful with the half-inch and inch sides if your block is not a multiple of an inch.  {I will not repeat these instructions each time.}


Step 3:  Rotate the mat clockwise 90 degrees.  Line up the ruler with the half-inch marks on the cutting mat and cut the right side.


Step 4:  Rotate the mat clockwise 90 degrees.  Line up the ruler with the inch marks on the cutting mat and cut the right side.


Step 5:  Rotate the mat clockwise 90 degrees.  Line up the ruler with the inch marks on the cutting mat and cut the right side.


You now have a perfectly squared half-square triangle!


5 comments :

Shannon said...

I used a 9.5 inch square ruler to trim mine. But I don't have all the sizes. That would be ideal! I have trimmed the way you described too. Great tutorial.

Brenda said...

I've generally used any of a variety of rulers to square up blocks. Most long rulers have a 45 degree angle marked on them, so do square rulers usually. I have squares in a lot of sizes so can use them without having to use the mat lines. But -- I watched the Bloc Lock ruler video and think I'm gonna have to get me one of those babies -- so easy -- cause I love half square triangles.

Patricia said...

Thank you for the tutorial. I like your this way.

Melissa said...

Why didn't I think of the 45 degree line up trick? LOL Thank you for this! Tis is going to save me from some wonky blocks :D

desertskyquilts said...

That's a great idea, but too late for me. I already have 8.5, 9.5, 12.5 and 15" square rulers. LOL And 7 and 6.5 and 4 and 3.5. You were probably too young to blog when I was buying all those. ;