2022 Mar BOM - 9 inch Half Rectangle Triangle Block & 6 inch Quarter Sq Triangle Block

09/28/2022 3:00 PM | Gail Luther (Administrator)

Previously posted by Em Komiskey on stlmqg.blogspot.com


Welcome to Month Three of the St. Louis Modern Quilt Guild 2022 Block of the Month Sampler!

Remember to post your block to Instagram with the hashtag #stlmqgbom before the April meeting to be entered to win this month's prize. If you don't use Instagram, you may email a photo to the guild email. 

This month, you will finish EIGHT blocks! We will make four 9-inch half rectangle triangle blocks (8 total HRTs) and four 6-inch quarter square triangle blocks (QSTs). 

Coincidentally, if you are a member of the Modern Quilt Guild (and if you are a member of STLMQG, you are, by extension, also a member of the national organization), there is a full downloadable article about HRTs in your latest issue of MQG Journal, so go check that out if you want to learn more. 

If you still haven't had enough, here is a great resource for HRTs from Swim, Bike, Quilt

Now that you have all the info, let's go ahead and get started with our HRT blocks! We'll continue with the QSTs below. 


Make 8 HRTs that will finish at 4.5 x 9 inches (5 x 9.5 inches unfinished) for a total of (4) 9-inch blocks (9.5 inches, unfinished). 


Since we want our HRTs to finish at 4.5 x 9 inches, we are just going to cut 8 rectangles that are 1.5 inches wider and 2 inches longer than our finished size: 6" x 11". 

I used 4 background color blocks and 4 foreground color blocks, but you could mix it up and skip the background here, or use a print as your background instead. 

Now, cut half of your rectangles on the diagonal from top left to bottom right. Cut the other half of your rectangles on the diagonal from top right to bottom left. 

Side note: You can cut them all in the same direction diagonally, but if you want a diamond or elongated pinwheel in your finished blocks, you must pay attention to the direction of your diagonal cuts. 


Match up two halves of a HRT, and line up right sides together along the diagonal cut. There will be a bit of the point that will hang over the edge at the ¼ inch mark. 

Sew along the diagonal to connect each pair. 

Correct trimming is important in achieving an accurate HRT block!!

We are trimming our HRTs to 5x9.5 inches. I used a dry erase marker to make a dot ¼" in from each corner. When trimming, this is the mark you will use to line up with the diagonal line of you HRT. Your ruler most likely will not line up squarely with the HRT when trimming. It will be slightly askew, but you are using your diagonal as a guideline for trimming. 

Now, pair up your individual HRTs and sew them into 9-inch blocks. In the final quilt, you might choose a triangle, diamond, or elongated pinwheel arrangement. 



We will make four 6-inch (6.5 inch, unfinished) QSTs.


Cut 4 squares at 7¼". 


Start by making half square triangles. If you're new to HSTs and you just jumped in to this Block of the Month, you can head back to the January block for more detailed directions. Line up two squares, right sides together. Draw a diagonal line on the back. Sew a scant ¼" to each side of the drawn line. Cut apart on the line. Iron open. 

Now, repeat the process, using two different half square triangles that you just completed. 

Place two HSTs right sides together. Be sure to line up the seams on the top and bottom blocks. Draw a diagonal line from corner to corner so that it crosses perpendicular to the seam in the HST. 

Again, sew a scant ¼" to each side of the drawn line, cut apart on the drawn line. 

Iron open. Trim to 6.5". 

St. Louis Modern Quilt Guild is a 501(c)3 non-profit organization. 216 Parkland Ave, St. Louis, MO 63122

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