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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.

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  • $\begingroup$ The brass rods don't sound like a great idea for the long term. If you have them on hand and want to use them for a week while you wait for case hardened steel shafting to come in, sure. Trashed (paper) printers and copiers can be a nice source of shafting and bushings, especially if you are 3d printing whatever they mount in and so able to customize for them. $\endgroup$ Apr 14 '16 at 15:59
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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.

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  • $\begingroup$ The rod and bearing fit almost perfectly with maybe an average of 0.05" play. I'm looking at using a belt driven system with optical encoders. I've already tested the encoders and steppers with my driver and its compatible. $\endgroup$
    – Dexter
    Apr 3 '16 at 19:29
  • $\begingroup$ .05" is a huge amount of slop in a 3D printer. The general goal is <0.005". And 1/4" brass rods will be very floppy unless the span is very short (like <6" maybe). $\endgroup$ Apr 3 '16 at 19:37
  • $\begingroup$ @RyanCarlyle Thanks, that was one large concern as part of this question. This is just a throwaway build for learning, do you think it will work for that purpose? I will go for much tighter tolerances in the next build. As long as it extrudes the filament far enough out to make up for the play, I'm not concerned with making it pretty. I just don't want it to not function at all. I guess that depends on my speed :/ and the slop in the rods will hopefully be taken care of by the rod tightening. It's only going to be about 8" of travel $\endgroup$
    – Dexter
    Apr 3 '16 at 21:30
  • $\begingroup$ Someone correct me if I'm wrong, but having about 0.05" of slop could inhibit the carriage's movement and potentially damage the stepper motors with the amount of extra load you'd be putting on them. The slop could take the rails out of parallel which has more of an effect the longer the rails are. So, I guess it depends on how large of a machine you're talking about for the first test 6"^3 might be okay, but anything greater would be risky. Also note the answer explaining rod length here $\endgroup$
    – tbm0115
    Apr 4 '16 at 14:10

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