I did test the buttonholes (of course). First with black thread, mainly because that was on my machine from a little in between job for a friend of my daughter. But it also helped to clearly see what the result of the buttonholes was. I also tried a buttonhole with a rounded end, but that is not my favorite on my machine, I don’t get that one quite right.
The first one on the left was the default buttonhole, center right with a different setting, top right with a filling tread. That was the one I chose to use, and I tried it with the right color thread too. This is the one bottom right.
And guess what happened? After 5 trial buttonholes with no problems the first one on the jacket went wrong!! I unpicked it and did it again, but what a pita!
On the picture below you can see the fill thread. You pull on the thread so that the closed side of the fill thread will be on the end of the buttonhole. This way it also reinforces the point that will get the most stress when the jacket is worn closed.
Here the thread is pulled through (on my machine it goes smoothly over the bottom thread, the upper thread usually gets a few stitches and can’t be pulled through anymore).
The tail ends are cut off and here is the front with all the buttonholes. I didn’t open the buttonholes yet.