A couple of questions about MPCNC and parts

Hello

I like the way MPCNC is built and I am in the process of finding the parts. I have a 3d printer myself (A reprap), but the tube I can buy has the following sizes:
Tube size = OD
3/8” = OD: 17,5mm
1/2” = OD: 21,3mm
3/4” = OD: 26,9mm
1” = OD: 33,7mm
1¼” = OD: 42,4mm
1½” = OD: 48,3mm
2” = OD: 60,3mm

None of them comes close to to the part sizes on Thingiverse, Will there be another size of printed parts, like 26.9mm or 33.7mm ?
Does it have to match exactly?

How good (how small) is the smallest amount (mm) anyone has been able to make a MPCNC move repeatedly?

Sorry for my English…

Best regards
Arnold

Are you sure you are looking at conduit? The sizes that are available have covered the 3 size globally so far. If for some reason your conduit is different buy stainless tubing, or shop online.

+/- .2mm is a good place to start.