Stainless Steel Conduit ?

I’ve seen some people posting about ways to strengthen the conduit, such as filling or other materials. While looking for the exact wall thickness of the conduit on McMaster, I ran across a stainless steel emt. Although much much more expensive, would there be any benefit to using stainless for more rigidity, particularly in larger formats? Also, would the stainless surface be smoother, or more straight?

I found this conduit here

If you are willing to spend more, get stainless steel tubing.

I have 2 different wall thickness pieces coming today or tomorrow. See if it makes much of a difference in rigidity. The thin walled stuff I have just deformed from the bearing load, it is smooth as silk though.

The stuff you have on the way is stainless? You tested thin wall stainless and it deformed? Where do you source thin and thick emt?


Yes stainless on the way. I have a fairly local shop that sells stainless tubes but I want to test this out before I make the drive. Yes the tin walled deformed, (0.0165") Pretty sure I have .032 and .065 or .092 on the way. The .0165 is just a bit less rigid that standard emt silky smooth exterior but too weak walled.

Emt I usually get from the hardware store.

Nice. Ill have to look around locally as well. I work at a facility where we laser cut and engrave stuff like this, but I don’t think anyone would cut me a deal on it.

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I just got mine from Fedex, looks real nice. I did a quick and dirty flex test. I will upload some pics in a new thread.

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Nice! Looking forward to it.

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as I’ve found - at my place it is much easier to get aluminum conduit, comparing to the stainless steel for building the MPCNC.
But I havent found any pros/cons on using aluminum tubes. Can anyone advise?

Yea, it’s been tested already. Doesn’t work, just deforms from the bearings.

Thanks Barry!
I think I’ve found the tubes, including cutting into appropriate sizes.

P.S. Sorry for noob question - but actually I haven’t found any specifications for conduit needed. All I’ve found is that it is not recommended to make any of lengths more than 1m without any support.
What is recommended thickness? (i found 1.5mm and 2.0mm. Going to use 1.5)
What about lengths of moving tubes ? (or they are the same as main dimensions?)
What is Z length?

My gantry rails are the same as the sides. Think my Z is 11ish inches.

@Sergey Drobyshevskiy
Have a look here at wall thicknesses, Stainless Steel – Quick and dirty flex test, I put the suggested thickness in a few places for Stainless, EMT is Standard and does need me to specify. Here,, is a calculator for sizes. Anything over 1M should have supports at least mid-span if not more.

Thanks a lot guys!! Due to some reason I missed that page in Assembly guide!