Very interesting, thanks Peter.
Reading it more carefully, I see Stevenson’s patent covered hydraulic jacks both vertically mounted and swiveling, so I suppose he was hoping for a variety of clients.
I notice in the Smith’s DW Sessions patent for the swaged top end that there is no mention of Stevenson at all.
I have two jacks here.
One has the swaged top end, and the bottom foot says Smiths Stevenson Jacking System.
The other has the dimple and grub screw top end, and the bottom foot says Stevenson Jacking System World Patents.
It seems to suggest that Smiths acquired control of Stevenson at some point from Jenks Brothers, and then applied their swaged end idea to Stevenson’s existing design. But as Roger suggests, they may have had other more important work than car jacks for a few years.
Back to the original topic.
Here is my initial brainstorming idea for a frame jacking saddle for SS and Mark IV, made from 4" channel x 5" long and a 1" x 1-1/2" x 4" block.