I have several old frequency pin routers with oil mist lubrication directly to the bearings. I've replaced one set of bearings on one machine with greased high speed spindle bearings. I've done this before with some success but I'm wondering if others have tried this?
(Solid Wood Machining Forum)
From contributor H:
Would 20,000 to 25,000 rpm overheat the grease in sealed bearings? I think liquefied grease may not lubricate as well as an oil mist.
As a rule, I don't like re-engineering stuff or "tweaking" stock tools or equipment to satisfy some ill-conceived notion but in this case it was necessary. I have another router motor however that is also in need of new bearings. I've been told that as long as the spindle rpm doesn't exceed the rpm rating of the greased bearings, I shouldn't have a problem.
I think though that I will probably just stick with the original oil mist system and stop trying to re-invent stuff. My old grandpa was good at re-inventing stuff until he had a whole workshop just chocked full of "special tools and equipment" (junk).
I agree with Contributor D though that some equipment improvements or alterations can be made, but I always give it more than a second thought. Years ago, my grandpa took his old babbett bearing jointer and lathe (both circa 1880) and cut them up and added ball bearings and electric motors. Of course this was the logical solution at the time but (as far as I'm concerned) he ruined two vintage pieces of equipment. To his credit (and though he's long gone) his lathe still runs fine but I had to junk the old jointer which was a real shame. It was once a pretty piece of Victorian machinery before he started welding on it.