I do packs and sacks: webbing, cordura nylon, heavy duty thread.
I also sew very lightweight sheer curtains.
This is the CG-500 (Commercial Grade 500),
They also make a CG-550 and a CG-590.
heavy fabrics need high top thread tension,
wound the thread around the bobbin tension disk to get it
A cross between a true commercial machine (often with only one stitch)
and consumer models that have way too many confusing features.
My sewing book said most should get a machine like this.