I have only had problems when trying to sew the velcro to thick fabric such as fleece or fur.
My suggestion is to just mess with the tension until you get it right. When adjusting tension only adjust about a half number at a time.
Make sure you put the needle down by hand and turn the wheel by hand until the needle starts up again, then use the machine.
At the corners I make sure the needle is down and then turn the fabric. Before using the machine always make sure your needle is on the up stroke.
If you stop and start again, make sure the needles is on the up stroke.
Occasionally I too have problems, but not frequently. |