Cob "Inner Tube"

After seeing a picture of a Dunhill pipe with an "inner tube" I wondered if I could do the same to a cob so that I could have a clear and consistent airway to the bottom of the bowl. Using a new 5th Avenue (Thank you Aristocob!) I drilled out the tenon of a Forever Stem to to fit the diameter of the tubing and then a few quick measurements and I had the tube cut to length. Using my dremel I had the end ground to an angle. Put her together and viola! I figured it took me a whole 20 minutes. A pipe cleaner passes clear to the bottom without getting hung up. I also have a consistent size (3.7mm) in the airway which I hope will improve the smoking characteristics. I'll try it out and report back at the end of the month.

I used 304 stainless steel tubing. 3/16" OD & 0.148" ID (aluminum would work just as well). I used a 3/16" drill bit attached to a hand tool and "reamed" out the opening of my Forever Stem. I used a bamboo skewer as a depth gage and cut the tube to length. Next came the dremmel on one end of the tube (a bench grinder would be far easier). Insert the tube into the stem. By reming the stem out by hand, the tolerance is nice and tight, therefore no need for glue or adhesives. Insert stem into the pipe and swab out with a pipe cleaner soaked in everclear to remove any manufacturing oils from the tube. Fill, light, smoke.
I smoked a bowl of Sugar Barrel last night. The draw was tight like a perfectly dilled briar. No gurgles or noise of any kind and the pipe cleaner went in and out with no problems. I can see this being a conversion on 6mm & 9mm pipes for people who do not like the big open draw of a filter pipe without the filter. Thank you Dunhill for thinking this up 100+ years ago and the Ebay pipe I saw which gave me the epiphany.
Here's a shot of the tubing & tools minus the dremel.

I thought about heat trasfer but that wasn't on my list of reasons for doing this. I suppose if you use aluminum you would get a better heat transfer. I read someplace that comparisons were done on the length of the pipe stems to see if a longer stem would smoke cooler. And it was concluded it made no difference. I own Falcons and I can honestly say they smoke no cooler than any of my cobs or briars so I figure its how you smoke that will determined if its hot or cool.

Just did a bent 5th avenue with the same stem. I now have my two pipes for alternating days of smoking pleasure. The bent pipes usually give me a little gurgle but it didn't this time. I fired it up with McClellands Beacon (packed a little too light) and she smoked all the way down with no dottle. The next load was Peterson's Irish Oak. Unfortunately a wind storm has kicked up while I was packing the pipe so it'll have to wait.
Overall I'm really enjoying the way these pipes smoke and how easily they are to clean with a pipe cleaner. If each pipe wasn't so unique I would think this could be an excellent kit to make up and sell through Aristocob or Walker Briar Works.
Oh well the wife came home and I have to start making some Green Chili for dinner.