Of course, your needle size has a lot to do with going through denim. But this one has too small of an opening/throat to be useful for larger projects or heavy materials. I am doing a quilt with two cotton layers and one warm-n-natural batting, and the machine struggles with it. It doesn't like thick layers. You'd be better off with a larger model that has metal innards. This one (as I found out AFTER I bought it) has a lot of plastic, so thickness stresses it. This machine is best for curtains, pillows, etc etc.