June Tailor, Perfect Half-Square & Quarter-Square Triangle Ruler

Perfect Half-Square and Quarter-Square Triangle Ruler.

   I found this great Ruler to make the "Perfect" HST [Half Square Triangle].
In the picture below you will see that there is three parts to the ruler. On the left is the part that you line the solid line up with the diagonal points of your square. Then using a marking pen you draw the lines you will sew on. The middle section is where you square up your blocks, the right section is where you cut your diagonal line from point to point on the block.

To create the HST to use with this ruler. You create a block from 1 7/8" up to 6 7/8" square.

Now here is where we have to have a discussion. Say you want a block 2 1/2" inches when done then you have to take it up to 7/8" [2 7/8"] to accommodate what your going to loose when you sew the two seems and cut down the middle. Some say that is too hard.. so they say just add a inch and cut down. so if you wanted 2 1/2" you cut two blocks 3 1/2". once done they will need to be trimmed back down to the 2 1/2" .... 

WELL, today I used this ruler for the first time. and I didn't even have to trim it!! It was PERFECT!! 

But I did check it to be sure. 

So let me take you through the process.   In this first picture I have before hand cut two contrasting blocks that were 5 7/8". They are to finish at 5 1/2" 

Then I turned them on point, and laid the Ruler on the block. This is the left hand side of the ruler. 

I lined up the center line from point to point on the diagonal. 

I then used my Air erasing purple fabric marking pen, and marked down the two slots, that are on either side of the solid diagonal line on the ruler. 

  Then I placed the block on my sewing machine. I lined up the right purple marked line with my needle. [I am also using my neat "Sew Easy Guide" on my presser foot to sew straight lines, see another blog post for that]  

   

  Then I sewed down the line. After clipping thread and moving block so the needle was lined up with the left purple line, I sewed down that line. 

After sewing down the two purple lines, I then removed the block, and took it to my cutting board and the Ruler. Using the right side of the ruler I lined up the two purple lines with the dashed lines on the left. This leaves a cutting slot up the center.

Once I have it lined up I use my rotary cutter to cut up the cutting slot between the two purple lines on the ruler. This separates the two HST's.

  I then open the two squares and press open the the block.

  Then I take it back to my cutting mat and the ruler and I line up the diagonal sewing line on the diagonal line of the ruler.  Then I move it along the diagonal line until the two sides are even with the 5 1/2" cutting slots. To trim any excess or overage if need be. OH MY there wasn't any to trim!!

  Then I flip the Block around to check the other two sides, and lay the ruler on the block again. I line up the diagonal seam, and the sides moving it to match the 5 1/2" cutting slots... OH MY it is perfect again!!! ha ha   so I didn't have to trim and the block is a perfect 5 1/2".

  That is what I call a great ruler!!!  

  Now this is only one of a bunch of ways to do a HST. You are going to have to try what works for you and choose. I will be posting more ways to do them as they are one of the "GO TO" squares used in blocks.

Hope this helps.
Becky