When we started making 18 to 30 foot ornamental and aeration windmills, we used a bearing in the center hub. Because they're so far off the ground this bearings never or rarely got greased and would eventually fail. From there we used a nylon bushing with a brass insert, but the stainless steel shaft would quite literally eat those things for lunch! Needless to say they squeaked and carried on, which made us research further and try to find something that would last but not require any grease. The Vesconite bushing has been the answer to our prayer. This material is awesome. It does not require any lubrication, in fact, it is self lubricating. We haven't replaced one Vesconite Bushing since we started using them 6 years ago.