I have a Dahon Mu P8 that I’ve stripped components and plan to powder coat. The issue I have is that I can’t fully separate the frame members. The long spindle within the hinge has no visible way to extract. A port is located at the bottom of the hinge to access the shaft. The end of the shaft is partially recessed but is smooth sided with no threads or flat sides for an Allen key. The top side of the hinge is blind (no shaft access). Anyone have experience with removing this spindle?

Inverted pic with the spindle access at the top

View into the access port showing the recessed spindle

Spindle is pictured on the far left of this replacement parts kit