I have no news, as I do have other stuff to make. And then, the servo-amp of my mill broke down. I have to repair that (but I have no clue about power electronics).
But I know how to harden.
Material is C45 (1045). Put in the oven at 840 °C, soaked and then quenched in water. C45 doesn't get too hard, so I left out tempering (would do it at 200°C).
Parts will be ground on my Myford MG12-M cylindrical grinder (that I reconditioned from scrap).
I intend to have a plain bearing at the pushrod with a bronze bushing. So to avoid galling, the pin has to be hardened.
The crankshaft axes don't necessarily need hardening. But they grind nicer when hard.
Right before the mill went kaput, I improved the process of making helical gears that will be needed for the cam shaft drive.
Nick