I use a lot of HST's in my work and have for over 10 years nearly every day.
So here are a few of the things I have learned.
It doesn't matter what method you use to make the HST's however I think my cut down method is the most accurate.
Cut down method and HST's
I do mostly scrappy so we cut swatches and sew them together and cut out a square from the center.
If I am making a lot of the same color HSTs I cut strips and sew two strips together. Open and iron the seam flat. Turn over center your template on point on the seam and cut out with your rotary. Make sure your template does not move as you cut. I use a mini mat and hold the template with the fingers on my left and swivel the mat between cuts with my right.
You can continue to cut them out til you get to the end of the strip and then pull the strips apart and sew the other two sides together and continue to cut.
Any leftovers we recycle into more blocks or smaller blocks.
Ok now for the prevention list. These are things to watch and be aware of so you won't lose your points!! Accuracy and attention to detail will help keep those points from disappearing!
1. Make sure your HST is truly square. If it is not gently trim it to square or as close as you can without losing the integrity of the HST
2. Make sure the seam is exactly in the middle of both fabrics on the corners.
This is one of the main reasons you will lose your points. If it is not exactly even on both sides of the seam then you need to gently trim to get it even.
3. MAKE SURE YOU KEEP A 1 1/2" SEAM ALLOWANCE BETWEEN THE
POINT AND THE EDGE OF THE QUILT BLOCK!!!!!!
4. When you join two HSTs you need to look at the seams and match them as closely as you can. I like to tack them so they won't move. Pins still will allow things to slide a bit more than I like.
5, Iron everything at every step. How can you get a good clean connection between blocks if the fabric is not crisply flat? If it is wrinkled at all it will affect the position of your pieces. If it is flat then you can better see what your are working on.
6. Check the accuracy at every step. (example)- Take a look at the 4 patch you just joined together. Does it look like a square or a rectangle or even a triangle? Now is the time to fix anything that is not square. Don't get so caught up in the steps that you don't look to see if the quality of what you are doing is ok or not.
Strategies to fix problem areas
1. Sew along the seam to fix any uneven seams(tightening a seam)
I chain sew and I join two's together. then I lay them on the table and look at each one and I pull any to the side that look like they are not straight lines.
If they are bowed in the middle then I start at the middle of the seam and sew along the seam and sew a little more to the left or the right depending on which side needs to be tighter or looser so the two will lay together in a straight line. (pictures below)
2. You can stretch cotton to some extent to make it fit.
3. If you find you have a HST that the point is too close to the edge
You can sew a seam along the first seam and the deeper seam will
allow for a 1/4" seam allowance.
4. If you have an HST that the point is too close to the edge and you
really don't want to mess with fixing it you can use a scant 1/4" or
a 1/8" seam to use as little of the fabric between the point and the
edge as possible and still have a solid seam.
Square HST where the fabric is even on the corners
The fabric is the same on each side of the seam.
The corner has one side of fabric bigger than the other side. This corner needs to be trimmed so the fabric on both sides of the seam are the same.