237. Chamfering Tenons for a Cooler Smoke

As you’ll be able to see in my restoration of the 1896 Kapp & Peterson catalog due out later this year from Briar Books Press, K&P has made non-System army mounts since 1891. There were, in fact, three of them. I’ve always liked the look of a great army mount, although very few have have reciprocated. Army mounts had completely dropped out of the catalog by the 1930s, returning in small numbers during the 1950s, with vulcanite ferrules, believe it or not. After those disappeared, there simply weren’t any until the comeback in the mid-1970s. Since then, they were a constant until the final years of the Dublin era, roughly 2014 to mid-2018, when they began being issued in ever-greater numbers but on what seemed like every new line or commemorative, always with a colorful acrylic fishtail.1  As each new issue appeared, I would look and sometimes find one I couldn’t resist, but time after time I experienced a hot, acrid smoke and while it wasn’t “once burned, twice shy” (more like a dozen-times burned), I finally woke up and realized that army mounts weren’t for me.

The 160 entered the catalog in 1906 as a “Peterson Patent Lip” shape

Then I saw the stem bend on this little 160 Sterling Army back in May. I fell quick and hard. I’d like to say it was a considered, rational decision, but it wasn’t. It spoke to me with the kind of piercing beauty that outweighs all other concerns. I didn’t care about the small bowl, the thinnish walls, the acrylic stem, the military mount. All I saw was the total package: beautiful bend, well-articulated P-Lip, sterling mount, rich ruby stain. I knew we were meant for each other, and before long it arrived from across the Pond.

If you’ve read this blog for long, you’ll know it’s my proclivity for virginias and va/pers that has kept me from this style of Pete. I’m not surprised that among those who don’t smoke these tobaccos there there are a great number who have no quarrel with an army mount. I’m a bit envious, but not to the point of giving up virginia tobaccos.I have also been interested in fluid dynamics (which I blame on Charles Peterson) and have long had a vague idea that chamfering helps reduce the friction of air flow and thereby cool pipe smoke. So I set out to give it a whirl, and sort-of succeeded, but also made a few bungles. At that point, a dim light bulb finally came on and I knew it was time to get on the Bat Phone and dial up “Professor” John Schantz. As always, he came through. Everything useful in this post is due to his patience in explaining to me the ins and outs of chamfering and its benefits.  He writes:

“Many of my pipes benefit markedly by chamfering the tenon, which also pretty much eliminates any stem gurgle.  Chamfering works especially well in non-System pipes (whether army or navy mount) with large shank-to-tenon gaps [like military mounts]. It works even better for pipes with the draft hole drilled at the 12 o’clock position, which is common in many K&P pipes. The small space under the draft hole acts as a mini-well, but the smoother transition of the funneled chamfer disturbs the airflow less, so less moisture drops out of the air stream.

“I would not chamfer a tenon that had very little or no shank-to-tenon gap. I might just barely touch the tenon with the chamfer if it happened to be slightly mis-aligned, thus smoothing out the airflow and also allowing a pipe cleaner to pass more freely.  This is because if there is no gap, there is no place for the smoke to expand, condense and drop the moisture, which means there is no need for the deep chamfer.  A deep chamfer would make it worse by creating a gap where none had existed before.”

“A second caveat: on pipes with a face-to-face tenon-shank fit [K&P’s “navy mount” pipes like the recent Tyrone and Deluxe Classics lines], I measure the gap between the shank and end of the tenon before I do any chamfering.  If the gap is very small, say less than 1/16″, then I will normally chamfer the tenon ever-so-slightly. If, however, the shank-to-tenon airway is not aligned center-to-center, then it is a perfect candidate for a deep chamfer. More than a 3/32″ gap, then I would chamfer deeper.

“In my experience, chamfering really helps with many non-System bent Petes or any pipe that has a shank-tenon airway that is not aligned [i.e., will not pass a pipe cleaner through to the bowl] and has a smallish gap.”

“If you look at the banner photo, you’ll see from left to right a Sherlock Holmes Squire and its stem, which I’ve deeply chamfered; a Tom Crean Great Explorers which has a factory-made extended-tenon cone like the Squire originally had; and a July 4th with a slight factory chamfer.”

“Going back to the Crean, the first thing I did was use the chamfer.

“The next thing was to use the tapered drill bit. This bit will taper the airway [reproducing the graduated bore effect of the P-Lip mouthpiece]. In my own experience, as long as there are no “steps” where the airway makes a sudden transition from one diameter to another, a pipe will have less stem gurgle.

“To spiff up the tenon after chamfering, I just use a little stem polish on a pipe cleaner, partially insert the pipe cleaner and bend it to the angle of the chamfer and swirl it around a few times.

Before going on to my “independent practice” of the Professor’s Schantz’s lesson, I should also say that I have three K&P army mounts that work really well for me: the 1904, 1905 and 1908 Antique Collection pipes seen above. I attribute my enjoyment of them to three common elements: the P-Lip, the graduated bore and the tenon chamfers. The 160 has the P-Lip  and with the Professor’s instructions, I think I can now modify it to include the other two elements as well.2

Here’s the materials I used:

Chamfering Drill Bit Set (called a Countersink Drill Bit set)
Tapered or Fluted Drill Bit Set, 3/16″ and 9/64″ (also confusingly called a Countersink Drill Bit set)
Micro files (John used a Vermont Freehand Stem Funneling Tool)
400, 600, 1000, 1200 grit sandpaper
Pencil with round-end rubber eraser or similar device for sanding the polishing the chamfer crater
Stem polish (I used the Before & After)
Variable speed hand drill (me) or pin vise (John)

Factory tenon airway

I began with the two tapered bits first, the  3/16″ then the 9/64″, to give myself a bit more of a guide hole as well as create the tapered airway. I’m comfortable with the variable speed drill in one hand and a firm grip on the stem in the other. I had the rpms about half-way up on the drill before inserting the bit. (I’ve torn and chipped an acrylic bit by trying to start the rpms after inserting the tip. It seems to grab the acrylic as it accelerates.)

After drilling with the tapered bits

Professor John told me on a separate occasion to be very careful not to drill past the bend in the stem with the tapered bit—or it will drill right through through. I did lightly run the round micro file around the perimeter of the inside airway at this point to make sure there were no fluted grooves or tearaway. I’m hoping John will remark in the comments section on whether this was a waste of time or simply wrong.


Here’s the chamfered tenon. I succumbed to the temptation to begin with a smaller diameter bit at first. I needn’t have bothered, as I had to drill deep enough to drill the first impression out anyway. Notice the acrylic “hairs” and tear away caused by the heat of the drill. Sometimes factory acrylic tenons can have a bad case of this stuff (see the Tyrone, for example).  Fortunately, it’s not hard to remedy.

The polished chamfer

I wrapped 400 grit sandpaper over the round eraser-end of a pencil and twirled it into the chamfered surface, following with 600, 1000 and 1200. After that, I daubed a bit of the B&A stem polish into the chamfer, then layered some t-shirting over the eraser tip of the pencil and twirled. It came out quite smooth.

The first smoke (with Marlin Flake) was amazing. I can’t take all the credit for this, as the factory bowl-coating always makes for a sweet first smoke. And as you can see in the photo above, the drilling was so close to the center on this pipe that it passes the dreaded “pipe cleaner test”—a great boon to good air flow. The mortise is 19.7 mm deep and the tenon depth is 9.7 mm, leaving a 10 mm gap (0.4 in). No gurgle, no moisture up the airway. The slightly heavier drag of the P-Lip / graduated bore was evidence that the mouthpiece was functioning in a traditional manner. Condensate on the chamfer, as expected. Smoked cleanly and coolly to the bottom of the bowl (and I filled it to about 85% of capacity). The P-Lip button, as you can see, is really wide and really flat. Made for easy clenching, especially in such a light pipe. I wonder if this is one of K&P’s newly engineered stems?


Many thanks to “Professor” John Schantz
for his patience in explaining this procedure
with detailed text, photos and emails.


1 Acrylic mouthpieces had been around for a very long time, of course. In fact, two of my first pipes from the late 1970s—a Jobey Stromboli and a Lorenzo Matera—were acrylic-mounts (which we referred to as “Lucite”). While only K&P knows the complete story for their switch to acrylic, much of it had to do with the oxidation of vulcanite, not so much for the smoker probably as for the retailer. If you’ve been in a pipe shop and seen a sun-faded vulcanite stem, you know what I’m talking about. Cleaning vulcanite requires both time and tools, and on either side of the sales counter not everyone wants to make the investment.

As the 1980s also marked a sea change in the hobby from pipemen who were primarily smokers and sometime collectors to pipemen who were sometime smokers and primarily collectors, there was also a slow transition from clenching the button between the teeth to one of cradling the bowl so the button wouldn’t get dental abrasions. YMMV, but that’s the general direction as I see it. Some welcomed acrylic, others loathed it and still others liked each for what it has to offer.

Between 2014 and the summer of 2018 fewer and fewer pipes at K&P were issued with vulcanite stems. But it seems like (to me) that public opinion began to change during those very years as artisan makers turned increasingly to high-quality German-made STEMA vulcanite (ebonite) rod for their creations. Sensitive to this (perhaps) as well as sensitive to the advocacy of vulcanite by Pete Geeks, K&P now seems to be trying to find a balance in the catalog between acrylic and vulcanite.


2 At the same time as the 160 Sterling Army, I chamfered a 306 Christmas 2019 pipe with its fishtail acrylic stem and a Great Explorers Tom Crean with a vulcanite stem. While I love both shapes, for me they have smoked just below the critical “meh point” (technical jargon for uninspiring, “inspire” meaning literally “to breathe in”). The Christmas pipe gave me the opportunity to see if the chamfer and tapered bore will improve a fishtail acrylic, while the Crean offered the possibility of seeing what deep chamfer and tapered airway would do on straight vulcanite. You can see that my sanding and polishing of the chamfers isn’t perfect yet. I need to find more flexible sandpaper and a better tool to use in sanding and polishing. The eraser end of the pencil, as you’d imagine, finally tore off. I began using the non-pointed semi-rounded end of the chamfering bit, but a ball shape would work better. Any suggestions?



Here’s one more 700 shape, a 742 SPECIAL from the collection of John Schantz. As you can see, the stem and the size of the bowl indicate that it was made at the same time as Brian’s 744 De Luxe.


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