new to 3D printers and to this community :)
Would a 1/4" brass rod with bronze bunting bearings for sliders and SAE 30 oil suffice for X and Y axes with moving extruder instead of print surface?
I'm gathering cheap/scavenged materials for a first time build, as a learning experience, and it doesn't need to work very long.
I just have no idea yet how heavy the extruders are, generally. I'm thinking of threading the rod so I can pull it tight for straightness under load.
Extruders tend to be quite light. An E3Dv6 complete with fan, shroud and wires is under 100g. Unless you use a Bowden extruder, you also have to add ~300g for a stepper motor. In any case, it will be quite light.
Sintered bronze bushings can definitely be used in a 3D printer; they're used in the (quite popular) Ultimaker 3D printers. I can't tell whether your particular bushings will work well, but I think the most important consideration is that there isn't too much play between the rod and bushing (but I'm assuming you took care of that). 3D printers don't place high loads onto the motion system.
"Proper" LMxUU bearings aren't very expensive either (reasonable ones can be had for less than $2) so if the bushings don't work out, you could always try those.