This has been test printed and used and works perfectly in multiple brand IDC fittings. I designed and made this as I bought a $10 plastic version and probably did 15 plugs and the plastic fingers bent over and the tool was a throw away.
When you purchase the wire inserter also purchase the IDC-156F Tool Handle so you can do all the typical plugs inside a pinball machine. The tool tip simply slides into the handle via the dedicated guide groove and inside the handle is a small locking piece so it will not fall out. The tool tip is double ended and depending on the material that you choose to get, the tip should last you a life time.
Search "SwinksIDC" for both tool parts when ordering. This is not just for pinball wiring but any crimping of IDC-156F fittings.
https://www.shapeways.com/search?q=swinksidc