Blog

by
Gary Hamilton, CPG

So, this all started at the 2022 Chicagoland Pipe Collectors show, and I’m sure that my smile tells the story of “my find”!  No, I didn’t go to the show with the express intent of finding this particular pipe, I was just thankful that we finally had a show to go to, and I was going!  No other expectations than that.  I was hopeful of finding a unique or vintage collectible Peterson (uh, aren’t they all collectible?) and that happened Friday morning at the pre-show “Smoke & Swap” out in the tent.  I say it happened in the morning, but I didn’t actually make the purchase until later that afternoon.  When I first eyed the pipe, I’m sure my head shook in slight disbelief, grasping with the thought that I was holding an authentic Patent-era Pete.  But clarity quickly set in as I came to the realization that this was in fact the 1990 Patent System Commemorative pipe (I’m sure at first glance this pipe has possibly fooled others as well).  None the less, still a unique and collectible Peterson.  The vendor and I traded comments and pleasantries regarding the pipe, but alas, I set it down and continued to peruse the offerings of other vendors.  After all, it was only early morning and there was still a lot to see at the pre-show event.  I have no idea how many times I returned to view that Commemorative “Pete,” and the vendor got a great kick out of it and was contemplating charging me “viewing rights” for any subsequent showings.  We finally agreed upon a price, and I had a new to me “Pete” for the collection!  Mark noted this as my “Unicorn Pipe.” Perhaps this is so, but to me it’s just another “favorite.”  Ask my wife about my favorite pipe, and she will be quick to tell you all of his pipes are favorites.  This one just happens to be my favorite from the 2022 CPCC show.  Now, on to the details!

The Initial Assessment

Once home from the show, the pipe sat on my workbench as I contemplated what, if anything, I should do other than a good clean and sanitize prior to firing up that first bowl.  Perhaps a pass across the buffing wheels to remove a bit of stem oxidation.  I inspected the pipe and overall, it was in good condition for having been previously smoked.  A few slight rim dings, but nothing major. Fortunately, no exorcism was required to remove any unwanted ghosting, and the bowl had a pleasant “pipey” aroma to it.  As Mark Irwin commented in a prior post, the pipe does have some incredible grain.  Unfortunately, my photography skills are somewhat lacking in highlighting the grain detail.  I’m sure it’s my antiquated camera and not me, right?

Even though the bowl had a pleasing aroma, the cake build up was a bit uneven.  I decided that I’d go ahead and clean up the bowl cake with a light reaming.  It was during this process I learned two things.  The bowl shows a couple of areas of some heat damage, and that my use of the camera flash still needs some practice.  I did not obtain any useable photos of the initial bowl reaming process showing the heat affected areas.  The resulting photo was that of a dark, black hole and nothing else. However, I’m sure you can picture in your mind the spider webbing type fissures we have all seen in pipe bowls subjected to heat damage from persistent puffing!  At this point, I set the bowl aside hoping that the damage was only minor.

Turning to the stem and threaded tenon extension, my initial assessment showed a couple of peculiarities that I was not expecting to see.  Perhaps I did see them at the show when first looking at the pipe, but in the excitement of it all, these peculiarities did not immediately register. Not sure that it would have made much difference, as I’m sure I would have told myself “I can fix that”.  As is evident in the photo below, the draft hole through the tenon extension is drilled off center, and is quite small in diameter.  Measuring in at only 2.8 millimeters (or about 7/64 inch) in diameter, this is much smaller than what I have come to accept in my understanding of original Patent-era Peterson airflow design and engineering.  Also of note, the diameter of the draft hole through the vulcanite stem measures to be 3 millimeters, and very little “taper” is evident.  This may be in part to being such a short stem?  Hmmm, this may look like a Patent-era Peterson, but it’s not exactly built like a Patent-era Peterson.

Another anomaly of this pipe as compared to Patent-era drawings, is the length of the screw in tenon extension.  When mounted to the stem and with the stem seated in place, the end of the tenon extension does not extend past the draft hole opening from the bowl into the reservoir chamber.  Measurement shows the end of the tenon extension to be approximately 1/2 inch short of even reaching the draft hole of the bowl.  From what I’ve seen in the Patent-era literature, it appears that for the screw in type tenon extensions, they were always illustrated as extending at least to the draft hole, and extending slightly beyond.  Once again, this pipe looks “Patent-era” but construction does not seem to be true to its origins.

As evidence, the Patent-era literature shown below depicts the position of what I believe to be illustrations of pipe and stem combinations with the screw in tenon extension.  Even if not the screw in type tenon extensions, the illustrations in all cases show the tenon to extend just slightly beyond the draft hole opening from the bowl.

Yet another item of concern I noted with this pipe’s screw in tenon extension is the length of thread on the aluminum tenon extension as compared to the threaded counterbore depth in the vulcanite stem.  The depth of the counterbore in the stem is about twice as deep as the length of thread on the tenon extension.

Using a 5.3 millimeter sized drill bit (a snug fit into the diameter of the threaded counterbore) I marked the depth of the threaded counterbore into the stem.  As shown in the following photos, you can clearly see the discrepancy in the length of thread on the tenon extension as compared to the depth of the threaded counterbore of the stem.

Measurements indicated that the length of thread of the tenon extension needed to be 0.520” in order to eliminate the larger diameter between the bore of the tenon extension and the bore of the stem.  The existing tenon extension thread length was only 0.238”.  An additional 0.282” of thread length is needed on the tenon extension.

Essentially, I need to “close the gap” of this diameter change in order to reduce turbulence and pressure changes yielding better airflow characteristics through the stem.  This design concept is discussed at length by artisan pipe makers in conventional briar pipe fabrication as the “tenon and mortise fit”.  More specifically, the length of the tenon should be the same as the depth of the mortise.  In practicality, the tenon is usually cut shorter by about 1 millimeter (or around 1/32 of an inch).  By achieving this type of fit, you ensure better airflow characteristics through the length of the stem.

So, from my initial assessment, I’m not that thrilled with the “engineering” of the tenon extension and stem.  I have not smoked the pipe in this “as found & bought” configuration, but I have to wonder about the “smoothness” of the draw? The bore dimensions just seem constricted to me.  Perhaps this all ties back to the condition of the bowl and the spider web heat fissures I found after the initial reaming?  I believe that in the pipe community it is accepted that a tight constricted draw typically leads to a hot burning pipe.  And undoubtedly a hot burning pipe will eventually yield the type of spider web fissures observed in the bowl.

A path forward.  I need to make some changes to the tenon extension, and to the stem, in order to improve airflow characteristics.  While I’m at it, I’ll do a deeper cleaning of the bowl and investigate the heat affected areas.  To finish up, I’ll buff and polish both bowl and stem.  The final step will be to apply the Arabic gum & charcoal powder bowl coating that Mark  has documented at length in several of his postings on Peterson Pipe Notes.

A New Tenon Extension

Unfortunately, the existing tenon extension offers no flexibility to make the needed corrections.  I most likely could center drill the draft hole to a more suitable diameter, but there is just no way to get the additional thread length that is needed.  And as already noted, it is just too short.  A new tenon extension will need to be fabricated.

First order of business is to correctly identify the thread profile, both pitch and diameter.  Using a metric micrometer and thread pitch gauge as shown in the photos below, I determined the thread was 6 millimeters in diameter with a pitch of 0.75 millimeters (technically noted as an M6 X 0.75 thread).  It was fortuitous that I just happened to have the correct sized metric threading tools needed for making this thread profile on the new tenon extension.

From my raw materials stockpile I found a suitable piece of 3/8 inch diameter aluminum rod; this will do nicely.  I set up my metal lathe with the appropriately sized collet chuck to hold the aluminum rod and installed a carbide cutter in the tool holder.  I made a few rough passes to turn the diameter close to the needed 6 millimeters for the thread, then using the micrometer I made the final clean up cuts to achieve the needed 6 millimeters, right on the nose!

I should note here that the length I turned to the 6 millimeter diameter for the threading operation is much longer than needed.  I’ve learned through experience that it is better to have a little extra material to work with in getting the threads cut, as it is sometimes difficult to get the first few threads started cleanly.  Once the work is fully threaded it is a simple task to trim to the length needed.

For this threading operation I’ll be using a hexagon threading die, turned by hand.  My metal lathe, a vintage 1964 Atlas / Craftsman, can be used to “single point” cut the threads under power, but at the present I do not have the needed metric change gears to do so.  For this operation, in a small diameter and in aluminum, the hand threading operation will do just fine.

Leaving the work piece installed in the collect chuck of the lathe, I installed the hexagon die holder in the tailstock of the lathe and engaged the die over the 6 millimeter diameter of the work piece.  It is now just a matter of rotating the die holder over the work piece while liberally adding cutting oil to keep the die cutting cleanly.  The photo below shows a general view of the tooling and process, complete with threads cut.

At this point the next step is to drill the desired draft hole through the tenon extension.  Due to the constraints of the 6 millimeter thread diameter, I will only be able to drill out the draft hole to 5/32 of an inch (or about 4 millimeters) in order to keep the needed wall thickness integrity across the thread profile.  In this photo I’ve got the drill chuck set up in the lathe’s tailstock and have started the drilling operation.  As is evident in the photo, long “stringy” chips are resulting, so drilling goes a bit slow as I stop to clear the chips.

Using the carbide cutter, the final operations to conclude the threading operation are to cut the threads to the needed length of 0.520” and make an “undercut” to remove the first 3 or 4 threads (of which I will explain about later on).

At this point, the threaded side of the tenon extension is complete.  After double checking my work to make sure everything is as it should be, I remove the work piece from the collect chuck.  At this point I install the appropriate size collet to hold the work piece on the newly cut 6 millimeter threads.  The nice thing about using collet chucks is that the jaws are cylindrical so that when you hold a threaded work piece, it does not damage the threads.

In the photo below, I’ve got the work piece being held by the threads in the collet, and a live center is mounted to the tailstock quill and is engaged into the previously bored draft hole through the tenon extension.  The live center gives the work some support, as at this point with the draft hole bored, the work is actually “flexible”.  The live center provided rigidity as the cutter engages the work to turn it to the desired diameter of 6.3 millimeters, same as the original factory tenon extension.  You may note that I’m leaving a portion of the tenon extension on the left, near the collet chuck, a bit oversized.  I will make a radius cut in this area to blend it into the tube of the tenon extension, very similar to the looks of the factory original.

In this series of photos, I’ve installed a circular carbide cutter into the tool holder in order to create the radius at the base of the tenon extension, just like the factory one.  The first photo shows the initial radius cut being made as I adjust the alignment of the cutter.  The second photo shows the radius being completed as it blends into the tube of the tenon extension. Almost finished!  The last step is cutting the tenon extension to length and dressing the end of the cut with a 45 degree chamfer cutter, as shown in the third photo below.  This chamfer cut helps reduce turbulence as the smoke is drawn into the tenon extension, and it just “dresses” up the finished edge.

The finished tenon extension, shown for comparison with the factory original.  Quite a difference in overall length, draft hole diameter and threading.  Overall, I’m pleased with the outcome of the new tenon extension.  Now to make a few adjustments to the vulcanite stem.

Vulcanite Stem Adjustments

As I noted earlier in my initial assessment of the pipe, the draft hole through the stem was about 3 millimeters in diameter, and showed only a very slight taper, if any, occurring near the “P-Lip”.  My goal on this phase of the refurbishment is to enlarge the 3 millimeter draft hole through the vulcanite stem, matching the 4 millimeter diameter of the newly fabricated tenon extension bore, and create a more pronounced taper. This will keep the overall scope of the refurbishment in line with Charles Peterson’s original design.

For this operation I will be using a 5/32 inch (4 mm) tapered drill bit.  I will do the drilling “by hand” using a hand held chuck and minimize any chance of damage or mistake!

Here I’ve got the 5/32” tapered drill bit positioned against the stem to the approximate depth That I want to work to, and I’ve marked the drill bit with a Sharpie marker so I know when to stop.

With the tapered bit held with my hand chuck, I slowly start the tedious task of enlarging and tapering the draft hole through the stem.  In getting the bit started, I frequently check alignment to ensure I’m staying in the existing draft hole, and not wandering “off center”.  Finally, I reach the predetermined depth mark, and success is at hand.

The last phase of the stem preparation is to ensure the threads in the counterbore are clean and extend fully to the bottom of the counterbore depth.  The photo below shows the starting threads of the counterbore to be in great condition, I don’t think the tenon extension was removed very much, if at all.  There was a moderate amount of tar accumulation at the very bottom of the counterbore that needed a bit of attention to remove.  This tar buildup occurred in the “gap” between the end of the original tenon extension’s short thread, and the bottom of the counterbore in the stem.  The new tenon extension design will eliminate future tar build up as the “gap” will have been eliminated.

To clean the existing threads, and cut any additional threads needed near the base of the counterbore, I’ll be using an M6 X 0.75 bottoming tap.  A bottoming tap is designed to cut threads into a “blind” hole to within 3 or so threads from the bottom.  A you may recall, I made an “undercut” on the new tenon extension, removing the first 3 threads.  Since the bottoming tap will only get you to within 3 threads of the bottom of the counterbore, I needed to remove 3 threads from the tenon extension so that it will fully seat when threaded into place.  The following photos show the bottoming tap, handle, and process underway.

Here we have the newly fabricated tenon extension, the original extension and the stem all laid out for comparison.  Quite a bit of difference to be noted!  From a machining and manufacturing perspective, especially on a volume scale to make a lot of parts, I easily understand why the original tenon’s thread length is much shorter than the threaded depth of the counterbore.  The tolerances for length and threading are less stringent, and no secondary machining operation is needed to make the undercut.  However, for the hobbyist repairman / maker, taking the time to do so is all part of the fun!

At this point, I assembled the new tenon extension to the stem and seated the stem into the pipe’s shank.  As you can see the aluminum tenon extension is visible below the draft hole from the bowl into the system reservoir.  Using a fine pointed marker, I made a reference mark on the tenon extension through the bowl’s draft hole.

Again, limited by my photography skills, it is somewhat hard to see the progress made on cleaning up the tobacco chamber in addressing the heat affected fissures. You can almost make out the chamber wall details in the previous photo showing the shot of the tenon extension through the draft hole.  Fortunately, only a light amount of sanding with some 150 and 220 grit sandpaper wrapped on a suitable sized dowel rod cleaned up the bulk of the spider web fissures.  There are still some fissures evident, but I did not want to sacrifice losing wall thickness for the sake of completely eliminating them.  Besides, I was going to apply the Arabic gum and charcoal (carbon) coating as advocated by Mark Irwin, and very similar to what Peterson currently uses at the factory.  As previously noted, Mark has documented this bowl coating process in several postings in Peterson Pipe Notes.

For the bowl coating, I followed Mark’s recipe using a 1:1 mix ratio (by volume) of the Arabic gum and charcoal powder, thoroughly mixed with small additions of water until I achieved the consistency I wanted – not too thick, not too thin!  You’ll know it when you see it.  It’s best to make a few practice batches just to see how this material behaves.  My bowl preparation following sanding and prior to coating application is to use a dental pick and wire brush to lightly “scrub” the fissured areas.  The goal is to dislodge any dust and debris lurking in the cracks, but not dig the cracks any deeper.  A few blasts with compressed air will help ensure the bowl is clean.  The only departure from Mark’s coating application technique that I’ve employed is to liberally coat the interior of the bowl with water prior to applying the mix.  Using my finger, dipped into water, I scrub the chamber, dipping my finger back into the water several times as needed.  My goal is to get a good “dampness” to the chamber wall, but not saturated.  This step actually cleans off a bit more debris particles, and I believe it helps the bowl coating mix make a little better adhesion to the chamber walls.  I’ve only recently added this additional step to the technique, so I do not yet have enough data points to determine if this will be of any benefit in the long run.

Below is a photo of the bowl coating after curing for a few days.  I’m going to let this cure out a few days more before trying that “first bowl”.  Ah, the anticipation!

So concludes my story of refurbishing the Peterson 1990 Patent Commemorative.  I hope that you have enjoyed reading about it as much as I did in the workshop tinkering with it!  My “unicorn pipe”?  Maybe so, but it is definitely a favorite!

Postscript

Following what seemed like an eternity of waiting for the Arabic gum & charcoal bowl coating to adequately cure, the day finally arrived to try that “first bowl”!  During the waiting period, I kept rolling through my mind what should be the tobacco of choice for the all-important first bowl.  Something old and familiar, or something completely new and unknown to me?  I decided to go down the “something new” fork of the road.  While at the CPCC show, I did manage to pick up a few tobacco samples, one being Sutliff’s Aromatic English. It just sounded interesting to me.  This blend is comprised of Black Cavendish, Burley and Latakia.  Although not an overly reviewed tobacco, the reviews posted are favorable.  So here we go!  The bowl was packed with the utmost of care, the charring light was flawless, and with a nice plume of smoke. Now for the final light and the anxiously awaited moment of truth.

My expectations on the smoking “mechanics” of the pipe were met, perhaps even exceeded.  In hindsight, I suppose I should have tried at least one bowl before I made the modifications to the tenon extension and stem, to have a data point for comparison purposes.  But alas, I didn’t.  I believe that I had already convinced myself that the initial engineering was not optimal, so don’t even try it…Hindsight, what a peculiar thing.

What I can say is that after smoking a bent System for many years, there is a subtle difference to smoking the straight System.  Okay, I sometimes can get a bit carried away with my tamping efforts.  I think most of us can relate to the concept and the resulting constricted draw from heavy-handed tamping.  With the bent System, it’s an easy matter to remove the stem and with use of a pipe cleaner through the draft hole, open the offending constriction.  However, with the straight System, the draft hole is in a position that a pipe cleaner through the shank will not produce any favorable results.  Ah, the Peterson “Gratis Tool” to the rescue with its pick, down through the top of the bowl and all is good.

As for my choice of “first bowl” tobacco, I’m intrigued.  Intrigued enough that I went ahead and jarred up a 1 pound order to put into my tobacco hoard.  Time will tell.

Now, about that Arabic gum & charcoal bowl coating.  A tip ‘o the hat to Mark Irwin, and the folks at Peterson for the insight about this coating recipe.  That first bowl was a pure delight.  As have been the ones that have followed.  The tobacco tasted good, really good.  The pipe performed flawlessly.  I don’t believe it ranked into the “magil” category as described by Fred Hanna in his book The Perfect Smoke, but I know a “good smoke” and this was it.  The bowl is starting to form a nice cake and the bowl coating is staying intact, no problems at all.  It might have been just my initial excitement, and combined with my unfamiliarity with the tobacco selected, but that first bowl had a “sweetness” to the taste I’ve not noticed before.  Was it the bowl coating?  In subsequent bowls, I didn’t notice that initial “sweetness”, but it was still a sweet smoke, if you catch my meaning.  The photos below show the start of cake formation and “ashing” after the third bowl.  I’ve had a lot of fun with this project.  I hope you have enjoyed reading about it as well.