You can create you own Tap.
The normal Tap length will not be sufficient to be used for a long
thread in a tube.
You will end up making a Tap to fit your project.
Since you have the die a long tap can be made by getting an
appropriate size of Drill rod.
Drill rods come ground to size and are usually made of steel that
can be hardened.
Check in Mac Master or any other Industrial Supply Catalogs.
The Drill Rod should be annealed so you can work on it. After that
it has to be fluted (two flutes should be enough). Then the starting
tip has to be tapered. You have to now use your Die to Thread this
Fluted Drill rod to create your Long Tap.
Regards Kenneth Singh
46 jewelry Supply Inc.
46 West 46 St,
New York, NY 10036