Those are pressed in fittings, as they don't have the clearance for a threaded fitting. ... they are usually pulled out over time by using a grease gun that was not released properly and yanked it off. Usually, the holes have been blown out/deformed. They do sell oversize press in zerk fittings, but just putting a zerk fitting in the end of the grease gun and holding it there will usually work fine, or just spray a lube in there as well as the shear pin holes and ends of the augers, and spin the augers, works fine as well, as many don't even have any zerk fittings. You just want to assure that the don't rust weld to the shaft over time from not moving. You want to pull the pins annually to assure you have free movement as well, in order that the shear pins will do their intended job.