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I'm using the Pimo rounded bits to do my drilling. They work really well, and give a nice round bottom. That, however, is my problem. When trying to drill the air hole, the point where they connect gets higher and higher as the angle increases. On an OP this can be more than a quarter inch or more above the bottom. Any suggestions on how to keep it closer to the bottom?

T3pipes wrote:I'm using the Pimo rounded bits to do my drilling. They work really well, and give a nice round bottom. That, however, is my problem. When trying to drill the air hole, the point where they connect gets higher and higher as the angle increases. On an OP this can be more than a quarter inch or more above the bottom. Any suggestions on how to keep it closer to the bottom?

Depending on how much bend there is, you have to drill the smoke hole short. Then drill the bowl down until you hit the smoke hole at the back of the bottom of the bowl. Try laying the bowl drill on your drill line, and you can see where the edge of it will interesect with the draft hole drill.

The smoke hole will be sunken into the back of the bowl a bit, but that's the only way I know to get it at the bottom of a steeply bent pipe.

Rad

RadDavis wrote:

T3pipes wrote:I'm using the Pimo rounded bits to do my drilling. They work really well, and give a nice round bottom. That, however, is my problem. When trying to drill the air hole, the point where they connect gets higher and higher as the angle increases. On an OP this can be more than a quarter inch or more above the bottom. Any suggestions on how to keep it closer to the bottom?

Depending on how much bend there is, you have to drill the smoke hole short. Then drill the bowl down until you hit the smoke hole at the back of the bottom of the bowl. Try laying the bowl drill on your drill line, and you can see where the edge of it will interesect with the draft hole drill.

The smoke hole will be sunken into the back of the bowl a bit, but that's the only way I know to get it at the bottom of a steeply bent pipe.

Rad

Exactly the same way I do it. Took me a pipe or two to realise my mistake however, lol. I made up a acrylic template for my drill bit so i can use it to help me layout lines and see easily where the points will intersect.

Thanks.

If you are willing or able, making a sligtly more blunt (less tapered) chamber bit will also help the situation. The air hole looks huge if the angle of the airway is similar to the angle of the bottom of the chamber. If you can punch it through the wall of the chamber, and have that be right at the bottom, that's the ideal.

FWIW I've never seen a commercial pipe exceed 40 degrees as an angle (from horizontal) for the airway.

I don't have the skills to make a tapered bit (I only have pure round), so what i did was as suggested above and shorten the air hole drilling a bit, drilled the tobacco hole down to where the air hole just broke into the chamber, then took a dremel and cut down towards the bottom of the chamber from where the two intersected (red lines).



This kept the chamber from getting deeper, and moving the hole further up the side.

Bingo.