This may have all ready been touched on but I want to make sure everyone know’s about it. There is a side cover right above the electrical part of the rotary switch on the G4003G. It is a cover for the lead and thread screw shafts. There is an oil port that can only be accessed by taking that cover off. I saw this cover mod online months later! When I first got my machine I took that side cover off, and took it over to my mill, and made a counter bore, that I could put 2 o-rings in so when the cover was on the oil holes were sealed against the machine case, and oil could not run out between the cover and the case, thus not get to the bearing’s in the machine. I still did not notice this other oil hole. I have attached some pictures, if you study them you will figure it out. Basically you mill away part of this cover with a mill, and then make a sliding cover you can slide and access the lead screw oil port! The pictures show the one on the web and the one I made for my machine!
Take Care Bob in Oregon