Thanks guys. Yes, it was labor intensive, but the original one had a clip that retracted into the body and extended at the push of a button. The end also had puzzle pieces that you could post the cap onto the body with. It also had randomly colored puzzle pieces. Now THAT was work!
There were manufacturing issues in getting the parts, including some mechanism parts that were laser welded, to all keep the level of precision I needed for that to work. Parts were made on several different machines, so zero points were lost in the various operations. I had to make complex fixtures to do each of those steps, but I saw that it was the aesthetics were off a bit. I didn't like the pen body being as short as it was and the cap was too long. I couldn't fit the retracting mechanism into something shorter, so I went back to the drawing board and extended the body one puzzle piece and subtracted one from the cap and made the clip fixed.