This would be allowed from my understanding of the license. You are not gaining commercial advantage or monetary compensation from "selling" it at cost to your friend once

So your friend buys all the components and a case of beer (or non alcoholic equivalent) and asks you to help assemble it?

I believe you can. I'm not a lawyer, but over the years the NC clause of Creative Commons has been interpreted to mean that you can't make a profit from sales of the product; recovering your production costs has typically been allowed. I believe that there used to be an example to that end on the CC FAQ, but I'm not sure.

In any instance, the copyright holder is allowed to offer additional or alternate terms. They may very well say "you can sell a printer made from these plans, but the sale price may not exceed your cost of the materials used" when they release it.