I started to make one like this using 2 solid 3 inch rods. I knurled one to grip so the wire would be grabbed and pulled into the crusher. As said above, it splits the jacket making easy stripping. One slot on the "stripinater" had a spot to feed whole Romex to split the outer jacket. The machine had springs that would allow the gap between the rollers to spread ( a safety to protect the cutter wheels on the other wire feed slots) and made this section less useful. I got side tracked and never finished making my own.