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Double needle tips
double needle tutorial
use double needle, but on the wrong side
How to use a twin needle with tips and tricks for hemming with knits and how to use it for decorative stitches.
Troubleshooting your twin needle stitching
Pintuck feet and needle sizes
How to sew with a double needle.
Great info on what size double needle to use with which pintuck foot
Sewing with a Double or Twin Needle
Sewing 101 - OneTip That Changed My Double Needle Sewing
Sewing 101 with Katy, Sewing with a Double Needle
Double or twin needle sewing tips