but is 1.4mm down not too short for enough threading?
No, it's fine. You're dropping from 5 thread diameters engaged to just over 4. Anything over 2 is mostly for adjustment rather than final strength of the threaded connection. You might see a couple of turns of thread poking out of the bottom of the nipple when they are finished, but the other way round means your wheel build will never be finished.
No, it's fine. You're dropping from 5 thread diameters engaged to just over 4. Anything over 2 is mostly for adjustment rather than final strength of the threaded connection. You might see a couple of turns of thread poking out of the bottom of the nipple when they are finished, but the other way round means your wheel build will never be finished.