OK, back online again.
The following is fairly long.
Randy, I did not, and do not, think that you are being argumentative. Discussing ideas back and forth is an effective way to solve a problem.
Lets summarize where we stand at his time. Hopefully I've got things straigthened out in my mind.
1) Getting a replacement from the supplier is the best choice. Unfortunately, for our international members and those who are in a hurry, this may not be practical. It is for these people that we are trying to help.
2) Cut the refill to compensate for the error in the nib. If you are going to use the pen for yourself or as a demo (where you are the one replacing the refill) then this is an eaasy fix. However, if someone else is going to be using this pen, and changing the refill, then this might hurt your reputation for doing quality work.
3) Attaching a ring either to the nib (very weak) or to the threaded tube (stonger) may be doable if you can make the ring. Per Ken's and Randy's suggestions, a ring could be made from a brass tube using a utility knife and a dowel for suppport. The amount of threads that are engaged will be reduced and may be easily loosened. Perhaps applying a coat of CA to the threads and allowing it to fully cure will tighten the connection enough to prevent it from coming loose during use. How well this will work is unknown until someone actually tries it and reports the results.
Randy reports that the length of the ring would need to be about 0.07 inch. This could be reduced if it is acceptable to allow the refill tip to extend slightly farther than normal but less than what Serge's photo shows. Maybe 0.04 inch would be enough. That would allow more of the thread to be engaged.
4) Push the transmission back to compensate for the nib length. This is where most of our discussion has been. Basic instruction on how to push the transmission has been presented. Randy indicates that on his assembly there is a rolled crimp to help hold the transmission in the stepped tube and moving the transmission by 0.07 inch would push it past this crimp. So, how do we make sure that the clamping force between the stepped tube and the brass portion?
The location of the brass/stepped tube interface is such that the only stresses that it will see is when a) the upper and lower portions of the pen are pulled apart or b) trying to twist the mechanism farther than the normal range of motion. Again if a little excess extension of the tip can be tolerated then the amount of correction can be reduced and the amount of contact area is increased. Ken's idea of using a utility knife can be used to produce a new rolled crimp on the stepped tube in a more easily controlled manner than using hobby sized tubeing cutter. CA can also be used to reinforce the press-fit.
Another idea I came up with is to produce an inside-out crimp at the end of the brass portion. This can be done by using a tapered end on a transfer punch. You want the tapered portion to make contact with the inside edge of the brass simmilar to using a tube insertion tool for gluing a tube in a blank. Place the end of the transmission on a hard but resilient surface, put the tapered tool in contact with the brass (inside edge) inside the stepped tube and gently tap the tool with a hammer. This will cause the end of the brass to be pushed outward against the stepped tube resulting in a greater clamping force.
I believe that the solutions presented above have now evolved to the point that most of us could make them work.
Any other ideas, comments, suggestion, or concerns?
Paul in AR