A 1:1 Physical Representation and Exploded-View Presentation of Selected Components of the Second Iron Hand of Götz von Berlichingen

Background/Objectives: The second iron hand of the Franconian Imperial Knight Götz von Berlichingen represents a historically significant and mechanically sophisticated example of an upper-limb prosthesis. Its internal mechanism, documented by Christian von Mechel in 1815, comprises articulated phalanges, springs, locking levers, pins, and additional components integrated within the hand corpus. A previous study reconstructed the internal finger mechanics using three-dimensional computer-aided design (3D-CAD), finite element method (FEM) analysis, and a functional prototype at an enlarged scale of 2:1. The present study has a different and narrower objective: to produce a nominal 1:1 physical representation of selected components derived from that previously published CAD reconstruction and to present them in an exploded-view display. The work addresses visualization and protection of the display model rather than mechanical actuation or conservation of the historical artefact. Methods: Existing 3D-CAD data from the previously published 2:1 reconstruction were uniformly scaled by a factor of 0.5 using Autodesk Inventor Professional 2027. Preliminary fabrication was performed using fused deposition modeling (FDM) with polylactic acid (PLA). Because the preliminary prints did not reproduce the smallest features with sufficient visual definition, resin-based additive manufacturing was used for the final components. The components were arranged in an exploded-view configuration on a black acrylic-glass backing plate, with a transparent cover, wooden frame, LED illumination, labels, and a separate historical image display. Results: The selected CAD components were scaled to nominal 1:1 dimensions and incorporated into the display. The assessment of the two printing approaches was qualitative; no measurements of printed-part dimensional error, surface roughness, repeatability, or mechanical performance were collected. Resin printing was judged visually more suitable for the intended display than the preliminary FDM trial. Conclusions: The work provides a physical representation of selected components from a previously reconstructed CAD model. It does not establish the exact dimensions of the surviving historical prosthesis, demonstrate a complete 1:1 reproduction, or validate a functional mechanism. The display has potential for teaching and exhibition, but its educational effectiveness has not been evaluated.