tobacco chamber

For discussion of the drilling and shaping of the stummel.
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buster
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tobacco chamber

Post by buster »

I was wondering what is the preferred bit to drilling a tobacco chamber. Is it a ground spade bit, a regular bit, or a forestener bit. I thing a forestner bit would be the way to go but I don't know. Is the hole supposed to be flat or rounded.
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RadDavis
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Post by RadDavis »

HI Buster,

A forstner bit is no good. You don't want a flat bottom. Look at the pipes you own. I use S&D bits that I ground into the profile I want on a bench grinder.

Rad
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KurtHuhn
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Post by KurtHuhn »

What Rad said.

I prefer to use Silver and Deming bits myself for most of my work. Reshaping them is rather trivial if you keep a close eye on profile and spin them while shaping. I tend to take the rather spectacular route of spinning mine on a lathe and using an angle grinder to get the profile I want. Then I clean up the relief behind the cutting edge with a dremel.

An easier method, for beginners not accustomed to grinding metal, may be to use spade bits and reshape them to the profile you need. They're not as expensive as good S&D bits, so if you foul one up, it doesn't hurt your wallet near as much.
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buster
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bit

Post by buster »

Can you not shape the bit and just use it like it is ?
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JHowell
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Re: bit

Post by JHowell »

buster wrote:Can you not shape the bit and just use it like it is ?
Which bit? I'd suggest trying what you have in mind. I also find that the cutting edges on a shaped SD bit need some relief. Making a bit freehand so that the two edges are precisely the same takes some doing. The relief offsets a bit of unevenness so that one side doesn't cut and the other rub. Also, with a lathe spinning normally the cutting edge of the bit tends to be attacked first and be ground down more than the following part of the flute. It helps to spin the bit in reverse, gives a little "automatic" relief.
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Nick
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Post by Nick »

Here's what you're going for:
Image

or this:

Image

In general, take a look at this page:

http://pipedia.org/index.php?title=Pipe ... amber_Bits
buster
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bit

Post by buster »

Ok the pictures help but now I have another question. Since there is no point on the bit how do you find the center of the chamber, or do you drill the hole and make the hole the center wherever its at ?
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RadDavis
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Re: bit

Post by RadDavis »

buster wrote:Ok the pictures help but now I have another question. Since there is no point on the bit how do you find the center of the chamber, or do you drill the hole and make the hole the center wherever its at ?
Drill a hole, and you'll be able to find the center. It's the tiny little circle at the bottom. :P

Rad
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hazmat
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Re: bit

Post by hazmat »

RadDavis wrote:
buster wrote:Ok the pictures help but now I have another question. Since there is no point on the bit how do you find the center of the chamber, or do you drill the hole and make the hole the center wherever its at ?
Drill a hole, and you'll be able to find the center. It's the tiny little circle at the bottom. :P

Rad
lol.. rough crowd!

If you have the block layed out before you start drilling, you generally already know where you're going to drill your chamber. From that point, depending on your process, there's most likely already some guide for you to line up the chamber bit on center. Many folks use a forstner bit to flatten out the top before boring the chamber. This leaves a little dimple up there that can be used as a guide. If you don't do that, one trick I use is to actually have the bit spinning while you fine-tune the position of your block. It's a bit difficult to explain and maybe it doesn't work so well with the S&D bits, but for ground spade bits, I've found it helps get you as close to dead-on as possible.
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Frank
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Re: bit

Post by Frank »

RadDavis wrote:Drill a hole, and you'll be able to find the center. It's the tiny little circle at the bottom. :P Rad
LOL... No heckling! :twisted:

Buster, take a look at Tyler's videos: http://www.tylerlanepipes.com/modules.p ... on_a_Lathe
Whether you're drilling on a lathe or on a drill press, the basic idea is still the same. Draw guide lines on the side and top of the stummel.
Regards,
Frank.
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flix
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Post by flix »

My bits? What Nick said. I've only funds for the spade bits, the best I have are from Tim West at J.H. Lowe.
sshawl
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Post by sshawl »

I have always been intruigued with the idea of using a ball nose end mill for the tobacco hole. It seems logical to me that using a short cutter with a 3/4" shank in a rigid vertical mill would probably be the best possible setup. So I finally ordered a spiral 4 flute 3/4" ball nose end mill from Victors Machinery Exchange - http://www.victornet.com The model was RF-24 for $26.80.

The cutter showed up the other day I couldn't wait to try it out. I had a stummel set aside and drilled a 1/2" pilot hole with a forstner bit about 1/2" short of absolute bottom to allow for the radius of the cutter plus a safety margin of 1/8". The end mill cut like butter and left a finish so smooth it feels like it has been sanded to 320+ grit. I am very very pleased. A definite thumbs up from me.

I did make sure to clear the chips from the end of the cutter for that last 1/2" of depth about every 1/8" just to be cautious.

Hope this helps!
Steve
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Post by LatakiaLover »

sshawl -

I think the reason most carvers don't use those mill bits is because the resulting bore has flat, parallel sides. Most tobacco chambers are considerably more conical than looking into them from above seems to indicate, and the walls frequently follow a parabolic curve. It's a bit of an optical illusion.

Whether they haven't strayed far from that convention for purely aesthetic reasons or functional ones, I can't say. But it is what it is. If you are producing pipes for sale as opposed to your own use, it's probably something to keep in mind.
UFOs must be real. There's no other explanation for cats.
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Frank
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Post by Frank »

Steve
I mentioned ball nose bits as well as core box router bits on another thread. They both cut decent smooth holes.

The choice of bit often comes down to cost.
If you're working on a small hobby budget, spade bits are cheapest and easiest to self grind, including a taper.
If you're working on a medium budget & don't mind straight sided tobacco chambers, ball nose & core box fit the budget.
If you're really serious about pipe making, then specially ground tapered Silver & Deming bits or spoon bits are usually preferred.
Regards,
Frank.
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sshawl
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Post by sshawl »

Hi Frank,

Sorry I missed your previous post :oops: Thanks to LatakiaLover for his comments as well. I agree 100%. I should have been more careful with my post and should have qualified it.

I have always been curious about this.. Has anyone ever compared the the profiles from various pipe makers? Is there any info out there to determine if a certain profile is functionally better than another?

So much to learn!

Thanks guys!
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Frank
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Post by Frank »

sshawl wrote:Has anyone ever compared the the profiles from various pipe makers? Is there any info out there to determine if a certain profile is functionally better than another?
If you're referring to the inner profiles of the various holes, there has been a fair amount of discussion with reference to straight sided chamber versus tapered. Even more so with regards to shank & stem airways, the discussions have ranged over diameter, taper, v-slot, etc.
Each pipemaker has his/her own preference when it comes to these specs.

If you're referring to the outer profile of the whole pipe, I imagine the correct combination of the above specs are what provide the best functionality.
Regards,
Frank.
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pierredekat

Post by pierredekat »

sshawl wrote:Has anyone ever compared the the profiles from various pipe makers? Is there any info out there to determine if a certain profile is functionally better than another
My own choice of bore profiles depends a lot on the overall design.

It's like, I start off with some basic diameter for the tobacco chamber, say, 7/8 of an inch.

Then I have a certain aesthetic design in mind, so ... how do I start off with this particular diameter, maintain a certain minimum wall thickness, and get the bore down to where I can reach it with my draft hole?

Having a particular bore profile can be very crucial, not always, but on about half of the pipes I have made thus far, it's a make-or-break deal.

So I have just been grinding my own spade bits on a pipe-by-pipe basis. Sometimes I can reuse a bit I have already ground, and sometimes I can't.

But I have gotten pretty good at my grinding process, along the way. Originally I just did a rough grind with the hand-drill-and-bench-grinder method.

But here lately I have taken to doing a followup hand-sharpening on a whetstone, and that has resulted in a lot cleaner cutting with less smoke and/or wood discoloration.

The whole sharpening process takes about an hour, but it works for me, anyway.

As I build up my collection of bore profiles, I think I can reduce my need to grind a new one to about 1-bit-per-4-pipes. Basically, just whenever one starts getting dull.
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