Threaded Tube

UPDATE: I have significantly improved this thing, the new thing is at http://www.thingiverse.com/thing:172750.

This is a cost optimized threaded tube allowing large, sturdy and relatively light-weight structures to be built.

UPDATE: I corrected a structural deficiency by creating male-male connectors and female-female tubes. The issue was at the abrupt diameter step-down between the tube and the male threaded end. Now the tube prints strong and the connectors print strong (and can now have