I haven't sewed on a machine I wasn't able to stall, even my industrial servo motor machines. I have had to hand assist some sections of webbing with both domestic and industrial machines. You may have to sew all heavy sections by hand power with any domestic machine while the industrial will usually power through once you get it started or may break the needle. Usually the domestic machine will stall before the needle breaks. I would be quite happy having only the second machine I bought, a Singer 15-91. I have been searching for a better all around machine, both domestic and industrial, but the 15-91 is the one I would keep if I had to keep only one. If I was sewing everyday as a business I would keep an industrial machine. If sewing thick stuff, presser foot lift is the most important factor, IMHO.Good call on her part. The 403a is definitely a more appropriate machine. You may find that you have to start with the needle in the down position to help the motor gain the momentum it needs to power through thick layers, but it should work just fine for you!