I've never made a denim quilt, but....I've repaired and hemmed many a pair. So: I use C&C, but sometimes go with a heavier jeans-type thread also from C&C. Never had any problems with any of them, but I DO use my Bernina or my Husq-Viking to do them. I vaguely remember using my first featherweight to repair jeans way back when and it seems to me that it did fine. I have several vintage machines I COULD use, but I just "ain't sew inclined" anymore to repair and/or hem denim. Hope this helps a little! (By the way, the only one I will do denim for is either myself or, on occasion, my yard guy who is just too good to me for me to say no....
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