Blog by Greg Wolford
Not long ago I was asked why I go through the trouble of using a drill bit (the blunt end) to stretch out a tenon instead of simply pressing it down to enlarge it when I’m fixing a loose stem. (The original article is posted HERE) I answered with because it is less likely to bend or mushroom the tenon doing it this way but there’s another reason to use this method: “headspace”.
Ideally the tenon should fit snugly against the mortise with little or no “headspace” or gap. When a stem is loose enlarging its diameter is the best long term fix but the method for the fix has an impact on the pipe’s smoking characteristics on my opinion.
Pressing it down while it’s warm will increase the diameter but also shorten the tenon, thus increasing the gap or headspace, too, which is undesirable. By stretching the tenon to the right fit, you get a nice, snug stem and no increase in the headspace. If you are a listener to the PipesMagazine Radio show you already know the reason why this is important; and if you’re not a listener you should be! Anyway, the increased gap allows more gunk to build up in the shank and can cause a pipe to smoke wetter, neither are desirable things. So, again, in my opinion, the extra time and effort the stretch-method requires is well worth the investment.
rebornpipes 
Greg, I was just thinking, I have done the same thing using an awl or an ice pick that is slightly larger than the airway in the tenon. Works great and has a handle
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Oh, that’s an even better idea! That handle and needle file set I have had an awl that would work great for this! There’s a photo of it all on the “Stop the Noise” post.
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I think another reason from my experience Greg, Is that the method you advocate keeps the tenon the same diameter the entire length rather than merely flaring the end.
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A very good point; I don’t think that had even crossed my mind, Steve.
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Out of curiosity could you post a picture of the drill bit you use?
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I wrote about doing it here
But I didn’t post a photo of the bit. I’ll try to remember when I get home this evening to get a photo.
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