Positioning of airhole in bowl

[Charl]

I know that the airway is supposed to meet the bottom of the bowl deadcenter (except maybe on full bents, where it sometimes is near impossible), but I can't seem to find out how the positioning relative to the bowl should be.

Somewhere I read that the airway should be 1mm deeper than the bottom of the bowl, another said that the exact center of the airway should meet the bottom of the bowl, thus 50/50. But on a lot of shop pipes I've also seen that the whole airway ends above the bottom of the bowl.

Can somebody enlighten a poor rookie?

I don't know if all of the above makes sense, maybe I should get the wife to draw it and then try again?

[JHowell]

I believe that the bottom of the airhole should be exactly level with the bottom of the bowl. The airhole sometimes approaches at an angle less than 90 degrees (bent pipes) or more than 90 degrees (pipes with forward-canted bowls), but the bottom of the airhole should still be level with the bottom of the bowl. My opinion, of course, but I think it reflects the consensus.

[hazmat]

I believe that the bottom of the airhole should be exactly level with the bottom of the bowl. The airhole sometimes approaches at an angle less than 90 degrees (bent pipes) or more than 90 degrees (pipes with forward-canted bowls), but the bottom of the airhole should still be level with the bottom of the bowl. My opinion, of course, but I think it reflects the consensus.

This is what I always shoot for when drilling my stummels.

[Frank]

I've always assumed, what Jack said, is pretty much the norm.

[bscofield]

The only other line of thought that I've heard (except Jack's which is the one I ascribe to) is about having it off the chamber floor because of cake build up covering the airway... This does not make sense to me. If a cleaner is run through with even remote frequency there will be no cake build-up down there and the aero dynamics will be improved...

[Nick]

A few well known pipe makers shoot for a hair under the bowl, Barbi being the one that comes to mind. But level with seems to be the norm.

[Charl]

Shit! All 26 pipes that I've done so far drilled wrong! Have been going for 1/2 of airhole beneath bottom of bowl all the time, but it just didn't look right.

Just go to show again: this forum is WONDERFULL for stupid okes like me. We're sitting at the feet of masters. I would probably have gone on doing it my way (the wrong way) till the end of time!

Thanks!

[Frank]

Shit! All 26 pipes that I've done so far drilled wrong! Have been going for 1/2 of airhole beneath bottom of bowl all the time, but it just didn't look right.

If you can figure out how to accurately clamp your pipes under the drill without damaging them, you might be able to bore the chamber a little deeper. Experiment with your worst looking creation, because the chances of catastrophic failure are high.

[Charl]

Tried that before with a pipe I had problems with, Frank. Now that's a recipe for disaster!

I think Kurt once said somewhere that when you start off with pipemaking, you mustn't dwell too long on each pipe, just go on and do more. I'm that type of guy! I know what I did wrong, now I'll do it right on all the following pipes!

[TreverT]

Too-low drilling is the easiest problem to fix. Just mount your bowl drill in your headstock chuck, press the bowl onto it, and give it a few spins manually. You can easily shave your way slowly down until the bowl bottom is perfectly even with the airhole bottom. FWIW!

[LexKY_Pipe]

Trevor, I've used your technique numerous times, even in repairing pipes. Works great. If the oposite problem happens and the airhole is too high, you can use pipe mud to raise the bottom of the bowl.

[Charl]

Now why didn't I think of that, Trever!

I'll try it in the drillpress though, a lathe unfotunately is only in my dreams still.