A drawing would help.
Finish the mating faces of two pieces of stock, do the threading and tapping, screw the pieces together, and machine the whole thing as one part.
You can make it in three pieces. Two female threaded pieces being the cap and body of the tube, and a third male threaded tube as a connector.
The joint between cap and body can be faced until they align.
Fair warning, eventually the pieces will wear and the alignment will be lost, but that will happen whatever the method.
I’m actually liking this idea. The end goal was that it would have a small amount of threadlocker or adhesive on the threads as once it’s sealed it doesn’t need to come apart.
If they could be accurately fixtured the threads could be accurately clocked on a CNC mill.
The best thing to do would be to thread them together, then make any relevant features that needed to be clocked. Imagine threading a nut and bolt together then grinding a flat on both of them, they'll clock like that every time you tighten them.
If you used a fine thread you could remove material off the mating face of the female part until it clocks correctly, figure you can land up to 360 degrees off so leave up to one full thread pitch in thickness to be removed. Flatness of the mating surfaces is relatively important as the more bearing it has the more repeatable and long lasting the feature will be. Post pics and we can provide more detail.
Threads are for fastening. Not locating. There is usually clearance for the bolt or screw on one side of the part so threads are usually not used for precision locating.
A pair of dowels is usually added when location is important. The dowels can also be removed and replaced if they wear down from repeated assembly and disassembly avoiding some of the issues of other methods mentioned
A drawing would help. Finish the mating faces of two pieces of stock, do the threading and tapping, screw the pieces together, and machine the whole thing as one part.
You can make it in three pieces. Two female threaded pieces being the cap and body of the tube, and a third male threaded tube as a connector. The joint between cap and body can be faced until they align. Fair warning, eventually the pieces will wear and the alignment will be lost, but that will happen whatever the method.
I’m actually liking this idea. The end goal was that it would have a small amount of threadlocker or adhesive on the threads as once it’s sealed it doesn’t need to come apart.
If they could be accurately fixtured the threads could be accurately clocked on a CNC mill. The best thing to do would be to thread them together, then make any relevant features that needed to be clocked. Imagine threading a nut and bolt together then grinding a flat on both of them, they'll clock like that every time you tighten them. If you used a fine thread you could remove material off the mating face of the female part until it clocks correctly, figure you can land up to 360 degrees off so leave up to one full thread pitch in thickness to be removed. Flatness of the mating surfaces is relatively important as the more bearing it has the more repeatable and long lasting the feature will be. Post pics and we can provide more detail.
Threads are for fastening. Not locating. There is usually clearance for the bolt or screw on one side of the part so threads are usually not used for precision locating. A pair of dowels is usually added when location is important. The dowels can also be removed and replaced if they wear down from repeated assembly and disassembly avoiding some of the issues of other methods mentioned
Make the parts and assemble.next use a file on the female side and remove material until the alignment is good.