This is a remix of my gallon can spout.
This one has a spout that swivels. The spout snap-fits on to the threaded cap.
The straight spout is better than nothing, but I think this curved spout has more utility. Since a can's threads may vary, and since a gasket or sealing washer may or may not be used, the cap orientation can vary, and the spout's direction can be adjusted accordingly.
I printed this one in ABS, and the fit is good. The swivel is secure enough, and turns smoothly.
The plan is to print one in nylon, which can be used with acetone and similarly volatile chemicals.
Nylon is far more flexible than ABS, and its use may suggest a minor redesign. So, this project somewhat of a work in progress. I doubt there will be any substantial modifications to these files.
Photos and whatnot will be provided in the next few days. This post will likely be deleted at that time.
If required, one can convert this SAE file to suit metric print software. Scale up by a factor of 25.4