Have you measured your smooth rod straightness, so that it could be presented in any clear way ? If i roll my rods on a glass plate, yes there is some really minor movement, but in my oppinion no major fault.

I do have a dial indicator so that i can get, maybe, somekind idea of the play when turnin the rods on a glass, but what would be the minimum "goal" that i could accept to be straight enough ?

If the rods are curved (they always are to some extent), your axes will do that curve, too, and your prints will reflect that. In essence, you can allow as much rod curvature as you're willing to have surface curvature in your printed parts.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

The rods need need to be straighter than the minimum clearance between the bushings and rods for each pair of rods on an axis. If the rods are bent beyond that, you can at least try to make the bends parallel to get the curvature Traumflug describes. After that, the straightness requirement is a matter of what you can tolerate in your builds. Keep in mind, bent X and Y axes will cause bed levelling difficulties, limiting how low your first layer can be.

Here is a good source for shafting:


[www.boschrexroth-us.com]



.250 diameter on up....