Nope I don't steal designs. I just use designs of machines I already build. The slide piece is from my Rapier machine with a hole drilled all the way through it. I'm using my crank and connecting rod from all my machines and the spring comes from coil machines. Which yes you can change and make the machine do whatever you like. The spring give is a coil spring that can be compressed via the set screw in the top of the slide. I'm already stream lining the design for production. It is already evolving into a half Rapier II and spring coil machine. I've done lining and black and gray, lining felt like tattooing with a coil machine. I made it free floating so as to smooth any unwanted vibrations.