Using Delrin Tenons: Difference between revisions

The basis for this article originally appeared as a sticky on the Pipe Makers Forum, and written by [[Kurt Huhn]]:

Once you have a drill bit that you know will provide a consistent hole size, you're ready to start using it. Be aware, that the bit that provides the right hole size for briar, may be to small for drilling a hole in vulcanite or acrylic. You'll need to be sure of your drill bits before you start.

  - chuck the block in and line everything up along my construction lines for airway, mortis, and   

   tobacco chamber. I drill the mortis/airway first.

   (at this point I continue on with the airway and tobacco chamber, that's not covered here)

  - I chuck the rod stock and face with a 1-1/4" precision Forstner bit

  - I drill the stock somewhat more aggressively than the briar. Vulcanite, Cumberland, and  

  - continue to drill the airway in the stem

  - Slice off a length of delrin approximately the length I need. I usually go about an 1/8"  

   longer just to be sure I can bottom out the tenon in the mortis in the stummel.

   very well.

  - first, I take a triangle file and slightly deepen the grooves on at three points around the  

   circumference. Do not depen the grooves all the way around. The goal is to get a slight   

   stem/shank meeting.

That's it in a nutshell. Sounds like a lot of work, but it goes rather quickly for me as I tend to batch most of that by doing 3-4 stems at a time. Way less time than trying to hand turn tenons on a wood lathe. I also prefer the buttery feel of delrin as a tenon over vulcanite - but that's primarily a personal preference.

As with any aspect of pipe making, there are many ways to achieve good results with Delrin. The following method is constantly evolving, but may prove helpful to some in developing their own:

Note: If convenient, consider leaving the stem material in the lathe for the entire process (glue up and drilling). This prevents having to re-center it for drilling operations. Multiple sessions where the stem is in and out of the lathe can introduce problems, even with self-centering chucks.  

[[Image:Inlayed_stem_forstner.JPG]] [[Image:Inlayed_stem_facing.JPG]]

The diameter of the Delrin used for the tenon will largely depend on the pipe's final stem and shank diameter. It is critical that your drills match the Delrin you're using, especially with regard to the fit of the tenon in the stummel mortise. Both drills and Delrin very slightly, so some experimentation with speed, feed rate, and different drills, even of the same marked size will result it the best fit. Once you find a good drill, make sure you keep track of it. It may be advantageous to  use a different drill for the stummel than the one used for the stem material.

[[Image:Inlayed_stem_drillingforDelrin.JPG]]

Next measure and cut the section of Delrin to be used. Make sure you leave extra length to allow for trimming it to perfectly match the depth of the mortise. Here we are also gluing up insert material, so that is also accounted for in the length:

[[Image:Inlayed_stem_rounding_Delrin.JPG]]

   

[[Image:Inlayed_stem_dryfitting.JPG]]

These serve as excellent clamps. If possible, let all this sit overnight, or until well cured (5 minute epoxy will speed the set time in terms of clamping, but will still not be fully cured for some time. It is risky to drill and fit the stem assembly until it is fully cured). When ever possible, I leave the assembly in the lathe through the entire process. During cold or damp weather I leave the light down close over the assembly (as shown above) while the epoxy is curing.