Tubes: 25x4 Steel or 25x2 VA?

Very much the title.
Since its only a difference of 7€ prince doesnt matter.
I guess the precision loss by the 3d-printed parts are way higher than by the tubes, but im not sure if rust will be an problem. So i guess im better save then sorry and go for the stainless steel, or does the 25x4 has any other advantages?

I’m assuming the ‘x4’ and the ‘x2’ represent the wall thickness in millimeters. The 4 will be substantially stiffer than the 2, which can be a good thing for a CNC machine. There is also consideration about how the tubing is manufactured. The non-stainless may be DOM (Drawn-over-mandrel) tubing. Ryan ran some tests comparing stainless vs. DOM tubing of the same wall thickness, and the DOM tubing was noticeably stiffer.

Just my opinion: for the price difference, and if you are in a climate where rust is not a serious issue and/or you are building a larger machine, I’d go with the 25x4. Non-silicone paste wax can be used to keep the rust down on non-stainless tubing.

As a comparison point, most MPCNC machines not using conduit, use 1" x 0.065" tubing, which is a close comparison to your 25x2…slightly larger in diameter, but slightly less wall thickness, so there are no issues using the 25x2.

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Thank you so much for your in-depth answer!
Yes, the x is wall thickness in mm :slight_smile:
No, I don’t expect rust to be a big issue, so im gonna go with the cheaper and stiffer 25*4.

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