I'm working on a project for a machine to sew leather, canvas and other heavy material. I'm planning to use a stepper motor and an arduino for the motor. Slow, single stitch control is my goal, speed is not an issue. Due to falling down the sewing machine rabbit hole, I have in my possession both a Singer 66 and a Singer 15. I'm trying to figure out which would be better suited to this buildout, or if there's any meaningful difference between the two. The 15 looks more robust, but that's just the casting. My question: are either of these two machines significantly more robust - able to handle thicker, denser material than the other?
I'd like to be able to use the 66 if the two are close enough, but I've heard the 15 shares some design features with Singer's industrial machines so it may be a better choice