I do not know the tap size but this will fit the e-power I have an NOEGO and an e-power and have used this on both, it's sold at Jazz cartopipe watch the images and you will see it.
http://http://www.jazzcartopipe.com/#!14500--no-ego
You could also
buy an extra cone here but only black left in stock.
e-Power
and
You could then cut the cone down to just cover the threads.
or
If you look inside your cone you will see that it is an insert, you could drive out the insert from the cone you bought and then take it to a hobby store that sell tubes and find a tube size that the inserts fits snugly into. Hopefully you will need it in stainless or brass which is what they usually carry.
Hope all this helps.