[Latitude 28]

Pick you up some "Drill Rod" of the appropriate size....https://www.mcmaster.com/products/drill-rods/tight-tolerance-multipurpose-oil-hardening-o1-tool-steel-rods/. Machine it as is....after machining its easily heat treated.  Any machinist should be able to handle heat treating.  I'd be curious what the Rockwell hardness of the original pin.  Going a little harder should help with the scoring we see on these pins.