A friend of mine asked me to hem her daughter's pants. They were linen and had parallel lines on it. I wanted to duplicate that and I never used a twin needle before. I was excited to try it out.
It was very simple to use and it sews perfect parallel lines. I followed the manual on the correct way to thread the needle. My machine has a setting for the twin needle to prevent the needle hitting the presser foot and breaking.
You use two spools of thread and follow your machine's instructions for threading. Also, twin needles come in different widths.
This is the perfect way to sew perfect parallel lines and give your hems a nice professional look!