The Three-Plate Alignment Challenge
Three-plate molds separate at two parting lines: the main cavity separation and the runner plate separation. A straight leader pin can only guide the main separation. The runner plate floats free, relying on its own (often inadequate) alignment features.
How Stepped Pins Solve It
A stepped leader pin has a larger diameter base (guiding the main halves) and a smaller diameter upper section (guiding the runner plate). Each section has independent g6/H7 fit with its own bushing, providing precision alignment at both separation levels from a single pin installation.