Problem with premade Stem fitting Stummel

[custom300]

I'm working on completing my first pipe and need some suggestions on how to get the stem to fit nicely to the stummel. I am using a preformed stem from Pipe Emporium, and I am using Delron for the tenon. Everything is fitting up fairly well, but it appears that the center of the stem (area closest to the tenon) is keeping the edges from creating a real tight and smooth fit. In otherwords, its like that area is higher than the edges creating a tight fit at the center and a gap around the edges. I'm afraid if i start to make any modifications that it will create a chain reaction which will throw everything off. It is very close. Any suggestions on how I can take up the slack so it is a tight fit.

I'm sure if the diagram below is more confusing than helpful, but i've tried to illustrate with the ) an exaggerated depiction of what i perceive is happening between the stem and the shank.

------------ |----------
-stem )== | Shank
------------ |----------

[marks]

Two possible fixes:

1) You could chamfer the inlet on the mortise, and make a little depression for the center of the stem to fit in.

2) You could glue some sandpaper (say 400 grit) to the end of the stem, trim the sandpaper to fit the stem, insert the tenon into the mortise, and lightly twist. This will conform the end of the mortise to the end of the stem. Have to be careful to not put any sideways pressure on the stem when twisting, or you will not end up with a square shank end.

Which method would work best for you, only you can decide. I have done both, depending on what I thought would work best at the time.

[MikeStanley]

Option number one above is by far the easiest for me anyway. It doesn't take much of a champher and if done well, it looks very nice to boot.
Mike Stanley

http://mikes-pipe-site.tripod.com/

[KurtHuhn]

Chamfer the mortis - use a countersink bit to relieve the edge to that the delrin/stem joint has a place to it into.

Note: even if you turn a stem's tenon on a lathe, you still need to chamfer the mortis slightly to be sure the fit is good.