Ramped airway or notched mortis?

d6monk · Post by **d6monk** » Mon Feb 16, 2009 9:02 pm

Hi everyone.

I'm designing a 1/2 bent pipe for a friend right now, and after laying it out on paper it looks like I will not be able to drill the airway in the bottom center of the mortis. After reading through some posts here it looks like the two solutions to this would to either:

1. have the airway off-center in the bottom of the mortis and then "ramp" it with a flex-shaft to align it with the airway in the tenon
OR
2. have the airway centered in the bottom of the mortis and nick the outside edge of the mortis.

I was wondering which of these two practices was most acceptable. I myself would probably want the notched mortis that has no chance of changing the airflow of the pipe, but some people may find this the uglier of the two solutions.

Which do you guys prefer?

Thanks again!

Post by **KurtHuhn** » Mon Feb 16, 2009 9:31 pm

My rule of thumb is to nick the mortis if that face will be hidden by the stem. If it won't be hidden, you may either need to reduce the amount of bend, or use a larger mortis/tenon - or either in conjunction with ramping the airway at the bottom of the mortis.

Ramping the airway isn't really a big deal. You'll find that it doesn't change the character of the smoke all that much, and allows for a lot of flexibility in the shape of the pipe. I do it quite often with bent pipes, mostly to allow the pipe to pass the infamous "pipe cleaner test" with ease.

Have you got a sacn of your drawing? It might be easier to make suggestions if we can see what you're dealing with.

d6monk · Post by **d6monk** » Tue Feb 17, 2009 12:28 pm

Hey Kurt,

The pipe is not nearly so bent that the nick will show from the outside once the stem is on.

Here is a photo I took of my drawing:

Post by **KurtHuhn** » Tue Feb 17, 2009 12:31 pm

My suggestion is to nick the mortis.

ToddJohnson · Post by **ToddJohnson** » Tue Feb 17, 2009 1:47 pm

I would suggest a fairly shallow 3/8" mortise. Nicking the back of that mortise should allow you to center the draft hole right in the bottom. It's important to remember to nick the mortise first, as a separate step from drilling the airway. This allows a path for the drill bit. If you try to do it all in one step, the back edge of the mortise can deflect the bit moving it off track. If it wanders even slightly, you will end up with a misaligned draft hole.

Re: "ramping," avoid it whenever and wherever possible. It does create a "sump" in the mortise that will collect gunk and moisture. It does affect the path of the smoke and creates condensation. One thing to know is that many collectors--even collectors of very high end pipes--may smoke what they like to refer to as "light aromatics." When starting with a tobacco that has a high moisture content, a "ramped" airway can produce fairly drastic negative results.

Good luck,

Todd

Post by **KurtHuhn** » Tue Feb 17, 2009 2:00 pm

ToddJohnson wrote: Re: "ramping," avoid it whenever and wherever possible. It does create a "sump" in the mortise that will collect gunk and moisture. It does affect the path of the smoke and creates condensation. One thing to know is that many collectors--even collectors of very high end pipes--may smoke what they like to refer to as "light aromatics." When starting with a tobacco that has a high moisture content, a "ramped" airway can produce fairly drastic negative results.

That is something I would not have expected. But it does solve a couple puzzles.

d6monk · Post by **d6monk** » Tue Feb 17, 2009 2:56 pm

Thanks a lot Todd and Kurt, you are a huge help and provide some great information.

I will go with a shallow 3/8" mortise with a nick for this one.

Charl · Post by **Charl** » Wed Feb 18, 2009 11:37 am

Great stuff! Thanks for sharing guys.

kkendall · Post by **kkendall** » Wed Feb 18, 2009 1:41 pm

When I do a double drill;
After drilling the mortise and adjusting the block for the airway, I will 'start' the airway with an end mill the same size as my drill I use for my airway. The end mill won't deflect (not even a little), it creates a perfect notch, and gives the drill a small pilot hole at the bottom of the mortise so it will track on-line right to where I want it.

Don't know if this is good or bad - nobody suggested it to me - there may be much much better ways (as I have discovered when I find out how pros do things).

pipeyeti · Post by **pipeyeti** » Wed Feb 18, 2009 3:17 pm

Why not drill the airway first, then line it up to drill the mortise? That way you can adjust the depth of the mortise to get the draft hole perfectly centered. Anyone see a problem with doing it that way?

ToddJohnson · Post by **ToddJohnson** » Wed Feb 18, 2009 3:24 pm

pipeyeti wrote:Why not drill the airway first, then line it up to drill the mortise? That way you can adjust the depth of the mortise to get the draft hole perfectly centered. Anyone see a problem with doing it that way?

Yep. The bit you use for the mortise can grab chunks of briar and drill a very ugly and usually oversized hole. This method can sometimes work if you're drilling on a fairly heavy lathe with a 2-jaw chuck. Not to mention the fact that, if you're not exactly right with your airway drilling, you may end up with a 1/4" deep mortise.

Todd

pipeyeti · Post by **pipeyeti** » Wed Feb 18, 2009 3:52 pm

Sasquatch · Post by **Sasquatch** » Wed Feb 18, 2009 11:33 pm

FWIW, I have done a couple pipes the way yeti is suggesting (perhaps large mythical primates think alike). Accepting the possibilities of the disadvantages mentioned above, the one striking advantage is that you can drill your mortise hole edge RIGHT where the airhole edge is and avoid the aesthetics displeasure of seeing that little bit of drill-bit rub on the shank. As Todd mentioned though, obviously you gotta have your angles worked out to do this or it gets screwy in a hurry.

Personally, I don't mind a deep mortise, like a peterson system pipe, as long as the airway hole is such that it comes into the chamber in the right place. It's not as hard as I thought it would be to do it. That said, I have some pipes where the pipe maker wasn't careful enough in where that airway meets the chamber - again, as Todd says, you don't want to wind up with a 1/4" tenon because of where your airhole is....

d6monk · Post by **d6monk** » Wed Feb 18, 2009 11:34 pm

Speaking of short mortises -

With a 3/8" diameter mortis I was able to practically eliminate the notch with a small mortis chamfer on this pipe (airway is in center of mortis bottom too). I also used the method pipeyeti suggested (I was not yet aware of the disadvantages of it). The hole ended up clean, however, I ended up with a mortis only a little over 1/4".

So I was wondering how short is too short for a mortis/tenon? On my previous pipes I shot for a 1/2" mortis/tenon. I machined the tenon on this one a little tighter than on my first two pipes and it seems ok. What do you guys think?

Thanks again!

Sasquatch · Post by **Sasquatch** » Wed Feb 18, 2009 11:39 pm

Monk, you nailed the thing exactly - one of the advantages of a longer tenon is that it does not have to be as tight to be resistant to twisting. A stubby tenon has to be a much tighter fit, and of course, you run the risk of breaking the briar at some point. I know this because, er, well, let's just say a guy I know ran into this issue once, yeah?

How short is too short? I'd say shorter than 3/8" and you are in danger, but there are probably other variables that I am missing in this rigourous equation.