Hopefully it’s dry lube. Wet lube and routers is the devil.
Also, if your rods/tubes are out of round anywhere you’re going to have issues. If you’re using precision ground rods, then large machines are going to be ungodly expensive. You’ll also have to beef up your steppers to deal with the mass of the gantry. Now that you’ve beefed up your steppers, you’re going to find out rubber timing belts aren’t going to cut it anymore either. So you’ll either need to go with chain, which works quite well, or use a rack and pinion gearing system, which works really, really well, just not with this kind of gantry design.