So I’m searching around for a stainless steel tube vendor that will do the cutting for me as I’m lacking precision cutting tools.
I have a vendor who got back to me and said the ones they have available have a painted black coating, this isn’t good, right? It should be a smooth stainless steel surface?
What grade of stainless steel tube? I’m seeing 304/304L is the one used in mechanical applications.
Is there somewhere you would recommend I buy? Online somewhere, that ships to Texas?
@volrok welcome to the party! 
I built a LR yet but I bought my 25.4mm DOM for my Primo at Metals 4 U but I was close enough to pick it up so I didn’t have to deal with shipping. The online pricing was not up to date (higher) so I would call if one of the locations works for you.
You can also contact a local welding supply since most have DOM or SS available. Most welding supplies will also cut to size so that is another advantage to going that route.
I have seen a few builds use Summit Racing or Jegs since they are reasonably priced but it was cheaper for me to pick it up locally.
Best of luck in your new build.
I doubt the black coating will make any difference. Machines are made with galvanized steel conduit, which can be significantly rougher than any coating I can imagine applied to stainless steel. Just be sure it is really 25.4mm (1") in diameter and has an appropriate wall thickness. Most builds use 0.065" wall thickness.
304/L or 316/L Stainless tubing will both be applicable for the machine. It does not matter which one, just which ever is cheaper. The main differences between the two grades are corrosion resistances and properties like that. If you are building any axes over 24", I would recommend at least a .08 wall thickness.
Thanks for the responses.
I think I will try going with the painted black surface if it’s unlikely to make a difference. The invoice lists it as “mechanical tubing” so I’m hoping that’s the correct item.
My table is going to be 4’x4’, so I’ll also take the advice and go for the .08" wall thickness.
I’ve had most of the LR kit since January and am only now trying to get the rails and 3D printed parts. My friend bailed on printing them for me, idk why 
, so I’ll be ordering them pretty soon.
The paint will most likely get worn off very quickly as the point pressure where the bearings contact the rails is quite high. So you may need to keep an eye on them, and you may need to tighten up your rig if the paint was thick enough to cause things to loosen up when it does wear off. If you are in a humid environment, you may also want to put some non-silicone wax on those exposed surfaces unless you’re running your machine enough to prevent rust from general usage.