So, order of operations for the trunion, just to see if someone has an easier way to do it.
Cut an over length part on the bandsaw, with some extra for holding in the chuck, so I can do all diameters in one setup. Then face the end and turn OD with the steps. Bandsaw off holding stock, flip in the chuck and face the other end square. Or perhaps square it on the mill with the part in a vee block. Probably saves indicating it on the lathe.
On the mill, hold in the vise with the faced ends on the jaws. Mill one flat (center drawing), flip and use parallels against the flat to do the opposite side. Use the same setup to get the two flats with a radius (seen on the left/right drawings). Bore the bearing hole, drill/tap the holes. Rotate 90 degrees using parallels on the flats and cut the slot. Probably drill out, then clean up with an endmill.
Hold vertical in the vise with blocks on the flats, drill/tap the bolt circle in the ends.
Switch to rotary table, drill/mill the tapered holes. Mark lines with a 90 degree end mill. Stamp the numbers. I might need to work up a jig to line them up nicely.
Probably some deburring in there.. and a lot at the end.
Material is hot rolled, suspected 4140. I can use a forge to release stresses before machining if needed. Do we think it will be? I guess if it's not, all I'm out is a little propane and time.