My first step in repairing the tenon was removing the broken portion from the shank. This was easily accomplished by turning a screw into the draught hole and just pulling it out.
After some careful measurements were made, the Imperial Majesty @Emperor Zurg was commissioned to fabricate a replacement tenon insert. The result was beyond my expectations!
Next, I drilled out the pipe bit using a 9/64" drill rotated by my fingertips. The vulcanite material was soft and grabbed the bit easily. I was afraid of using a power drill as it would have a tendency to grab and rip the entire bit. I had to go back and forth and found rotating the pipe bit around a stationary bit worked best.
I did run into a bit of a snag as the vulcanite shavings got pushed into the draught hole causing it to become plugged. A pipe cleaner wasn't able to remove, but a stiff piece of thin wire from a marking flag was able to dislodge the debris. I was very careful to only drill as deep as the tenon insert.
After the bit was hollowed out, I cut appropriate threads with a tap into the opening.
The insert fit perfectly!
Next was to fit the tenon to the shank. It was turned slightly on the the large side to ensure a tight fit. I used progressive grits of sandpaper from 220-1000 to slim the tenon down to fit.
I will permanently secure the tenon in the bit with a drop of cyanoacrylate adhesive on the threads, but other than that,
Good as new!
THANK YOU for your guidance and superb skills Bill!
Once the super glue cures, I will be happy to be able to smoke this pipe again!
In the end, it probably would have been much easier and more efficient to just send it out for repair or just chuck it, but that would not have left me with the satisfaction I received by doing it myself.