I like the way to make half square triangles by cutting out a square, sewing 1/4" on all four sides and then cutting diagonally both ways. I just don't know how big to cut the squares to get the size you need. If I needed 3 1/2 " half square triangles what size would I need to make the original square and so on. Hopefully someone knows the math for this.

Alison, I know there is a tute on this on MSQC, where I learned this method, hope someone comes up with the URL for you, hang in there and I'm sure you'll get your answer.

I don't know the math on this but why don't you try making samples out of muslin. Maybe start with 4 1/2 or 5 inch squares and work from there. I think the quarter square formula was add 7/8 but maybe it doesn't work for your type of quarter square. Here is a link for the 7/8.

Alison. A 5-1/4" square would give you a perfect 3-1/2" triangle using that method. But I'd cut the square 5-1/2" so you have some wiggle room when trimming it. I love the Quilt in a Day ruler for doing this. You can square up the HST perfectly before opening it.

Wish I had a formula, but I just took squares of paper and started with a 6" square, folded it, Nope too big and on down until it came out right. There is a formula for making 8 HST but can't find one for this particular method of making 4.

I don't feel so bad now. LOL That was what I was thinking she could do is just make samples until she found what worked. I did see the 8 HST tutorial. At least you took the time to really help.

Alison, depending on how many HSTs you need with the same fabrics, the magic 8 method that Marie mentioned is really a good method.

The reason I like this vs. the 4 is because the magic 8 gives you 8 HSTs with no bias and the 4 cuts all your squares on the bias when finished. I prefer to stay away from the bias when I can.

Good luck with your project. Hope you post pictures when you are finished. Always enjoy seeing what others are creating.

Thanks guys. I did not know this method so this helps big time. I think most of my quilts have HST in them. The math for this is (unfinished size + 1/2") X 2. Can't wait to try this.