Hi Thomas,

Kroil is probably the best penetrant I have seen. Put a little on a rusted bolt and nut and usually quite quickly the nut will turn off with the rust now a redish-brown mixed with the oil.........

Humm? I can't quite understand why the general opinion is that light oil doesn't carry abrasives with it at times. Maybe sand will not stay in suspension, but sand shouldn't get into the tight fit of our hinge pin and lug in a double in good shape. It is the grit in micron size that becomes lapping compound and oil MAY CARRY IT IN EASIER! Grease actually catches small particles like a shield somewhat in the small amount forming a "bead" around our greased fit. A lot of operation may "blend" it in eventually; but I contend oil will do it faster and easier.
One shouldn't confuse the cleaning, flushing, filtering benefits of a pressure lubrication system with oil that is dribbled on with no new supply for a period. Dribbled oil no way has shock load like 50 psi pressure lubrication as well.
I have thought which machinery I have seen that sees some of the worst conditions. Rock and mining type crushing operations are among the worst for dust, grit, and HEAVY load. Oil lubrication if there is pressurized and well filtered. But by far and large the bearings exposed to this constant grit are GREASED with an E.P. quality grease. Engineers like equipment that can be greased often to flush and renew the grease and any contaminants within.
The very best protection on a double hinge pin IMHO is the same with the joint being cleaned thoroughly and re-lubed often.
I suppose one will use what they want as a lube on their hinge pin. I have only expressed what I use with many details as to why it is my choice.

Best, BigRx