I have learned that my press was missing part #43, the safety cam stop pin.
I put a 1/8 drill bit in the hole and now all is clear regarding the operation of the safety cam and #38-shell plate dowel pin.
For those who are wondering and don't know what it does, the safety cam toggles between two positions and is held one way or the other by the spring. When the tool head comes down, the angled face on #38 moves the safety cam against the direction of rotation of the shell plate. When the tool head goes up, the cam spring finishes the rotation of the cam and in the extream CCW direction, it blocks #38 and the tooling head cannot be lowered, thus preventing a double charge or trying to put a second primer in a primed case. Rotating the shell plate causes the loaded round to toggle the safety cam to the extream CW position and now the tool head can be lowered again. The safety cam stop pin extends up between the forks of the safety cam and limits it position in both directions.
I am using a taper crimp so I cannot use the safety cam feature. I like one suggestion I have of looking into the charged case before I place the bullet to inspect for no powder or double powder. The other suggestion I like is that when there is any kind of error or doubt in the operation to "clear the plate" and start from scratch.
Regards, Ray