An experiment concerning flared tenons

[Wet Dottle]

Today I would like to report the results of an experiment that was started nearly two years ago. When disassembling some pipes for cleaning, I noticed that some of the mouthpieces had accumulated cake in the stem. It was hard carbon residue that formed at the tip of the tenon. This was particularly significant in flared tenons, but almost absent in the others. The internet is full of comments stating that tenons should be tapered to improve air flow and provide a drier smoke and, consequently, better smoking qualities. I never found this to matter in my pipes, but decided then to check the hypothesis more carefully.

I started with four Il Ceppo pipes. These pipes were chosen because they all have flared tenons and, given enough time, all form cake in the flare of the air canal. Two pipes are straight, one has a 1/8 bend, and the other a 1/4 bend. One of the straight pipes is blasted, but all the others are smooth. They all have tenons that are nearly the same length of the mortise, are of the same brand and size (size 5 or 6), and all smoke very dry. Actually, they are all excellent smokers in every aspect.

I eliminated the flare in two pipes (the blasted straight and the one with 1/4 bend) by sanding the tenon. This created an air chamber of about 1/8 of an inch deep in the mortise. I then proceeded to smoke the pipes with every type of tobacco that I usually smoke, which includes everything except aromatics. I’ve been smoking these pipes since Christmas of 2008. In the beginning they got smoked once every two weeks, but more recently only about once a month.

The results are:

1- The pipes were cleaned after each smoke by passing pipe cleaners without removing the stems. They only required two or three of the regular cleaners (not the tapered ones or the fluffy ones, and not the bristled ones, either). The altered pipes required the same number of cleaners as the control pipes.

2- After two years, the pipes were disassembled for cleaning. The two unaltered pipes continued to form cake in the lip of the tenon. After two years of smoking the cake becomes substantial and needs to be reamed.

3- The altered pipes do not form cake in the tenon anymore, but they tend to accumulate fuzz in the mortise. The accumulation is minimal and was never removed during the two years that this experiment lasted. There was also some fuzz in the control pipes, but significantly less.

4- The mortise of the control pipes was cleaner than that of the altered pipes. The flared tenons were dirtier that the altered tenons. The altered tenons are easier to clean and do not need reaming.

5- The main canal of all the stems was equally dirty. The same is true with the shanks.

6- All the pipes smoked equally dry and well in all respects. I cannot detect any difference between them, as far as the quality of the smoke is concerned. That means that the altered pipes smoke the same before and after the modification, and that all four pipes smoke equally well regardless of the shape of the tenon.

In conclusion, this experiment does not corroborate the hypothesis that flared tenons contribute to a drier smoke compared to nonflared ones, at least not in any perceived way. However, the experimental conditions were limited to one brand of pipes and one smoker, therefore the results may not be generally applicable to other brands and/or smokers.

I would like to hear about the experiences of others. Thanks for reading.

 

[Sasquatch]

The idea behind counterboring a tenon face is that of all the places inside a pipe that are likely to accumulate moisture by condensation, this is probably the worst. If you have a pipe drilled a little small, 9/64 say, and any condensation occurs at the tip of the tenon, the result will be a gurgle. The theory of thing is that by widening the airway right there you help to keep the gurgle down by both having more room in the airway and hoping that the condensate runs back down into the pipe. I have seen pipes literally counterbored such that the face of the tenon is just slightly convex, and I have seen pipes that are deeply drilled, 1/2" or more into the tenon at about 5 degrees.

In a straight pipe, I would argue that this counterboring technique is unnecessary and even possibly counter productive.

As soon as a pipe is bent enough that the drilling angles are severe (that the airway cannot be terminated at the center of the tenon tip) I like to see a deeply widened bore. The pipes I have purchased and have made with this configuration work extremely well. To quote one customer:

"The full bent Hungarian/Oom Paul did not gurgle once. So that flared thingamagig worked."

Of course, that pipe MIGHT have worked as well without the extra detail, but I suspect not, based on my experiences with identically drilled pipes.

So I guess I agree with you for the most part - it's not likely to turn a bad pipe into a good one. It's a finesse that some pipes are improved by, and I would argue that done overly aggressively or unnecessarily, it could be detrimental.