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My son-in-law wants me to make him a straight Dublin. He is not a pipe aficionado, he just likes the shape. His expectations are in line with my inexperience.

The question I have is in regard to the shape of the chamber. I read a description of the classic Dublin shape that said, as I understand it, that the chamber should taper downward proportionate to the downward cone shape of the outside of the bowl itself. The source my be incorrect or I may have misunderstood it.

But if that is correct, how do you drill a tapering chamber? I'm assuming that would require a lathe?

George

Yes on the wall thickness remaining constant.

The easiest way to create a chamber of any shape is with a spade bit ground to the desired size/profile. Zip in a large pilot hole with a standard bit, then "scrape" the walls and floor to shape with the spade. If everything is sharp, you grind the spade so the trailing edge drops away, and your tooling is tight & slop-free, you'll get a beautifully cut chamber without tear-out.

Close enough to the taper of the outside will be fine. Really what you want to avoid is excessively thin areas toward the bottom of the bowl.

You can grind your own bit or buy one. The rawkrafted tapered bits are excellent, I am really enjoying using mine and the price is really quite good.

Thanks guys.

I have a Forstner and a spade (from Vermont Freehand). I normally use the Forstner first and then finish with the spade to make the bottom of the bowl round. But that technically does not give perfectly constant wall thickness for a tapering bowl like a Dublin.

However, on the one I'm carving now the overall taper of the bowl is mild so I think it will be close enough...especially since my 'customer' won't know the difference anyway.

I will take a look at the rawkrafted bits.

George

If you have a lathe, you can simply cut a narrow v-shaped chamber and open it up to conical by hand, but I think you are only drilling, in which case a bit of the right shape is your option, and as you say, the customer isn't likely to have calipers on it anyhow.

You are correct, I do not have a lathe. I am slowly getting my workflow down with just a drill press (which is nearly 100 years old). I would love to have a lathe but that isn't in the cards especially since this is just a hobby right now. But I watch videos of the workflow on a lathe and just drool.

I finished the Dublin a couple of days ago. It has some flaws (one of which I didn't notice until I looked at pictures of it.) I don't think my son-in-law will notice any of the flaws.

But, the good thing is that I got all the drilling done exactly right, possibly for the first time ever. Everything is centered and lines up. The stem and stummel junction is light tight. The fit of the stem tenon is just right. I know this is standard stuff but it has taken me a while to get my workflow nailed down. So that is one positive and another small step in the right direction.

George

It's standard stuff but possibly the biggest and hardest hurdle to get over. Nice job!

As for tapered versus standard tobacco chamber on a Dublin, as a general rule you want to taper the chamber. That being said, some less traditional Dublin shapes have thick enough walls that it's not necessary. It's your call as a maker and, as was mentioned earlier, the wall thickness is the main factor in the decision typically.