wmgeorge wrote:The "real" world in high speed commercial router machines is a lot different than it was say 20 years ago or back in the day. R&P and rotating ball screw is now a fact of life. Wear happens when you making money with your machine. The Income offsets the minor expense of replacing wear items. Most folks lube the R&P system at recommended intervals. Gerry (Ger21) has been doing this forever, and not as a hobbyist I would trust his opinion.
I have straddled both worlds, the hobbyist and the commercial over the last 45 years. The problem with most hobby machines (mine included) lubing the rack and pinion is that they are not covered and most lubes will just cake up with dust in short order. In my particular case the racks are outside the machine cutting area behind the bed rails and are upside down (teeth pointing down) so they do not get all full of debris. I have never lubed them.
Dust covers for things like ways, balls screws and r&p add quite a bit of cost to a machine. Not just the cost of the covers but the fact that they eat up travel distance like crazy. So if you want travel distance of 8' you cannot just add the space the bearing trucks devour to the rails and call it a day. Nope, you have to add a whole bunch of feet to the ways, which also means the base has to be several feet longer. It all adds up pretty quickly. Most of us hobbyist guys are not willing to absorb that cost.
BTW, I think you meant "rotating ball nut" up above. I first decided to use it when I saw an article in Machine Design way back in the late 70's discussing how it sped up the machine, reduced vibrations, reduced the required size of the servo motor and a whole bunch of other good things. So it isn't like I thought the idea up. The key at the time was to use a GoodYear HTD belt which IIRC was fiberglass reinforced and did not stretch. It may have been reinforced with steel wire, not sure anymore.
It has been interesting to watch and participate in all the changes over the years. Who woulda thunk it would make for a great hobby in retirement? One of my old boss's who knew everything there was to know (just ask him) told me when we were designing the laser cutters that they would never cut steel with them so there was a very limited market. What foresight that man had! Ten years later he visited our booth at IMTS which was chock full of large laser cutters cutting, OMG!! STEEL! I was nice and did not remind him of his prediction.