kellen46

OK, here goes
cut three squares, any size, just all the same size. I chose three inches. one will be the center, the other two will be the same as each other but different from the center. Take the two matching three inch squares and cut them once on the diagonal making four half square triangles. Sew the half square triangles around the center square so that the center square is now on point. Trim and square up to size desired. Measure the sides of the unit, cut two matching squares the same size as the finished unit. Cut those squares on the diagonal and sew on to finished unit mating the bias diagonal cuts to each side of the unit. You now have another square in a square unit. Repeat the measure, cut, sew sequence until the block is the size you want. The units will be over-sized, meaning you can trim them back to a quarter inch seam allowance or if you allow a larger seam allowance the square will seem to float. It is really a simple idea. the diagonal measure of any square is longer than the side of the square. So if you take a square and cut it into two half square triangles they will fit along the side of a same size square with plenty of seam allowance. Just take two same size squares and cut one on the diagonal and arrange it along the side of the other square and you will see what I mean. By doing things this way you are always sewing a bias cut to straight cut side so the bias does not distort with stitching. I suggest you just try this and you will see how it works. If it is still unclear just cut one fussy block, say five inches and then cut two five inch blocks along the diagonal making four half square triangles, just as you would if you were making square in a square the traditional way, now arrange them on your cutting table, play with placement and it will become clear. I sew in this order. Look at the center square, four sides, top bottom, right and left. I sew the right and left sides, do not trim off excess, just center the half square triangle as best you can, I eyeball it. Press, sew top and bottom hst's press and then square up the block by measuring for your desired finished seam allowance. This will also cure any wonkyness the block might have.
The reason this works for a charm pack is that they are all cut at five inches. So while you will not have two matching squares to use unless you have two charm packs to sort through. However if you use all different squares you will achieve a nice scrappy effect and blocks all of the same size quite easily. One unit of charms runs around 6.5 to 7 inches allowing you to make a 15inch block. Imagine this separated with some sashing and you have a happy scrappy quilt. I hope this clears it up for you.