Half square triangles. Mmmm, every blog I read before I attempted my ‘HST’s’ made it appear these are easy. And perhaps they are…if you have measured perfectly, and cut just so, and sewn your ¼ inch seam with accuracy. But I can speak from experience & say that I for one am not so good at getting all three of those steps to work as well as perhaps they should. And that leads to half square triangles that don’t align perfectly in the corners. And that can be a little frustrating to say the least!
Thankfully I decided to start with a small project – a cushion cover – rather than a whole quilt.
I wanted to use up some of my 5" charm square stash for these projects, matched to a coordinating plain fabric. Each cover ended up using 12 full charm squares and part of one extra square. I used the technique where you sew all the way around 2 squares with right sides together and then cut 2 diagonal lines to get 4 half square triangle squares.
The turquoise cover was my first attempt & I learnt a lot - even the second half of the turquoise cover has better aligning seams than the first, so I am optimistic that the second cushion cover in purple (using the same pattern) will be much improved technique wise.
There are plenty of blogs stepping through how to cut half square triangles, so I won’t reinvent that wheel. But I am going to jot down some of the key things I didn't find out readily from the net, and instead worked out through trial and error (with a few mutterings under my breath from time to time!!).
Cut 12 x (5 1/8”) squares from coordinating plain fabric (plus make one extra square). My charm squares never seem to be perfectly 5” or perfectly square, so I decided to cut the plain fabric squares at 5 1/8” to give me a bit of breathing space when stitching together.
Place a charm square on top of a plain fabric square & stitch all the way around. I found it best to start stitching part way down one side (rather than in a corner) to avoid puckering where the stitching meets. And it was worth taking time to get the ¼” spacing accurate at each corner - sometimes I shortened the stitch length towards the corner to help with that.
Then open and press each triangle to get the HST squares.
The first big mistake I made with the turqoise cushion was deciding not to square up until I had sewn 4 squares together into a 2x2 block. Botheration & bollocks. For the purple cover I squares up the individual squares first & that worked way better.
I lined up my 45 degree andgle on the ruler with the seam and then trimmed down the first 2 edges (right and top), making sure I still had room to trim when I turned to square up the final two edges (in my case 3 1/8")
Next, spin the square around, line up the angle line again as well as the 3 1/8" size markers on the edge and cut the square to the size you want.
Once all the squares were sewn, squared up and pressed I decide on the design & took the all important picture.
I guess ideally I would have had an even number of squares but the size of the cushion needing covering dictated a 7x7 square cover. I worked in rows, sewing adjoining squares into pairs. When pressing I made sure to alternate seams either pressed to the left or right. This helped when then sewing up the 2x2 blocks.
A bit further along the way of joining squares together...
The final seam. I did find that once I was sewing more than 3/4 squares together in one go that pinning at the seams was definitely worth it to get good alignment.
Now the more tedious task of making them into cushion covers begins....