I have been pondering the idea to build a miniature model of an old timey car / wagon jack and have looked for a full scale model or suitable pictures for quite some time but have not yet found one like the one I remember from days gone by. As I remember, it did ratchet up mechanically, and a small click lever held it up while the handle was lowered to ratchet up another stroke. It worked similarly in the lowering mode. But I have been unable to visualize the the relative components and mechanical interaction of that jack and decided to build a model of one that I could visualize and whose picture I found on the net.
I did not photo document the build process since its design is very straight forward as evidenced by the finished model. And yet its operation is quite sophisticated in that the effort and resistance arms are configured on different planes and anchored on an elbowed fulcrum point allowing it to lock-over at the completion of the stroke. I didn't invent this mechanical marvel - only learned to appreciate it more as I attempted to create a miniature version.
Since this model was built entirely from bar stock (brass), and no cast parts were used, it is noteworthy that it required some complicated and delicate silver soldering operations. On various parts, several soldering operations were performed in sequence employing different solder hardness under carefully regulated temperatures so that one soldering operation would not cause prior joints to overheat and fall apart. Several times I messed up and had to start over.
This was a challenging project that helped me better appreciate mechanical relationships and learn torch temperature control.
Comparative scale:
