I am done printing my Primo parts and I also have the needed hardware, my next question is what are the best and smoothest pipes/tubing that I could buy for the 25.4 version (1 inch). USA based. Or the recommended pipe? I have a large build so a stiff pipe would be ideal
Thanks in advance!
For the 25.4mm version you of course need to get 1" OD tubing. Although more expensive, I went with 304 Stainless Steel to avoid any rusting issues. Also, for large build footprints, I recommend getting atleast .083" wall thickness. If you want even more rigidity, go with .120" wall thickness. Its all about your budget really.
Ryan ran some tests and found that DOM tubing was somewhat stiffer than stainless steel. That was one particular batch of each, so YMMV, but it is the only data point I’ve seen on the forum concerning stiffness of comparable 1" tubing. You would have to periodically wipe down the DOM tubing with paste wax, since DOM tubing rusts.
Roughness is not really a concern. There are many MPCNCs built using electrical conduit, which is significantly rougher than any 1" tubing you will buy.
As Matt suggests, thicker walled tubing will be stiffer, but if used on the moving tubing, your steppers will be accelerating more mass. There is some debate on the forum on how much increased mass effects cutting. I’ve seen builds split the difference, putting thicker tubing on the outside rails, and using thinner tubing for the moving parts.
If you go with thinner tubing for the outside rails, you can gain most of the benefits of thicker tubing by adding mid-span supports.
Do you have a local place or bought the tubing online?
Metals supermarket and speedy metals are good online places. Supermarket has some local stores depending on where you live. I found 1" dom at rural king by the welding stuff.
I work for a structural steel wholesaler… But I can say that our “off the street” pricing is significantly better than the places that I see steel sold. If you can find a local place, then it’s probably a very good option.
Where I work, we don’t deal in stainless, and the only 1" OD DOM that we have is 0.065" wall, so that’s what my V1 machines are made with. (Except the Zen V2, which is conduit only.)
It’s worth a search for someplace that deals in structural steel. We get a lot of farmers, and people who manufacture trailers, as well as welding & fabrication shops coming in.
The downside is that we don’t sell 6’ lengths, or anything like that, it’s by the 20’ piece. I had to cut my tube with a hacksaw in the parking lot to get it into my car, but a 20’ piece here cost about what a 6’ piece would cost at a local retailer. (And I paid even less than that, about spilt the difference between what it comes out of the mill at and our cash sale customer price.)