Gritzner Extra 155 and Singer Extra 155 are completely identical sewing machines, only they have different names.
Many users have trouble threading this sewing machine, especially threading through the upper tensioner, this video shows winding thread, threading on sew machine, test sewing with a buttonhole sewing demonstration.
A special greeting goes to my relative who is the initiator of this video.
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‪@MasinskiKutak‬