Several more sessions in the workshop, and the yokes for the Stephenson’s links have taken shape.
The following photos detail the steps.
The finished yokes. 6 of them, each about the size of thumbnail. The time taken to make these tiny parts is not related to their size, except that the small size and delicate strength made the task more difficult. The time taken depends more on the number of setups and the number of machining processes. In this case, it took about 4-5 workshop sessions.
Drawing of the yoke, to measure the angles.
CNCing the end curves, 6mm end mill, 1mm cuts, 12000rpm, 600mm/min.
Marking out the angle cuts.
Milling the angles (not CNC)
Using angle plates to get as close to 12.6 degrees as possible. I used a 10, a 2, and a 1/2 degree plate to end up with 12.5 degrees. Close enough. The other side was 30 deg, easy with one angle plate.