Countersinking tenon?
Countersinking tenon?
Something that has been puzzling me since seeing Kurt's photo essay on stem making: Do you always countersink the tenon, or only do it in case of bent pipes where the airhole is not centered in the bottom of the mortise?
So far in all my pipes I have tried to get the tenon to fit as tight as possible against the end of the mortise, to try and get continious airflow without any gaps, from stummel to bit. And only with certain bents, I have countersunk the tenon.
I might be wrong, bit I've also assumed that the countersinking is to minimise sharp edges so that the pipe doesn't whistle.
Am I right?
So far in all my pipes I have tried to get the tenon to fit as tight as possible against the end of the mortise, to try and get continious airflow without any gaps, from stummel to bit. And only with certain bents, I have countersunk the tenon.
I might be wrong, bit I've also assumed that the countersinking is to minimise sharp edges so that the pipe doesn't whistle.
Am I right?
I always do it if for no other reason than it chamfers the hole at the end and takes off any sharp edge that could cause hairs from a pipe cleaner to gather in that spot.
John
www.crosbypipes.com
www.crosbypipes.com
Ok, I may be the only one here who is a little unsure of what exactly you are counter sinking here. Being new to pipe making, I'm not always up on all the small details that go into the craft. If someone could give a short description of what is happening in this process and where exactly it takes place, it would be very helpful. A picture would be good too. I'm sure that when it is described I will have a V8 moment, <hitting head with open hand> and say oh yeah, that part. Thanks for all the help and inspiration this site gives to people like me.
The opinions expressed above do not necessarily reflect those of the management or of the little green men who have been following me all day.
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This is a pic of me countersinking the tenon end:
And a link to the entire photo essay:
http://www.pipemakersforum.com/photo_es ... cut_stems/
(note, when looking for the above image, I noticed the photo essay was a little messed up with captions not matching, photos no loading correctly, and photos out of order. I fixed that, so it will make sense now. )
And a link to the entire photo essay:
http://www.pipemakersforum.com/photo_es ... cut_stems/
(note, when looking for the above image, I noticed the photo essay was a little messed up with captions not matching, photos no loading correctly, and photos out of order. I fixed that, so it will make sense now. )
Ahhhh, much better! <hitting head with open hand> Thanks guys. I guess I was confused because I think of a countersink more like what the mortise looks like, as in a flat bottomed hole. I would call that a chamfer but that could just be the terminology I learned working in a small engine factory after college. The pictures are great too BTW.
If you are trying to eliminate sharp edges for better air flow or to minimize the area for pipe cleaners to catch or to minimize condensation points, should you also countersink the air hole at the bottom of the mortise?
If you are trying to eliminate sharp edges for better air flow or to minimize the area for pipe cleaners to catch or to minimize condensation points, should you also countersink the air hole at the bottom of the mortise?
The opinions expressed above do not necessarily reflect those of the management or of the little green men who have been following me all day.
If you use a S&D (rather than forstner) type bit for your mortise, the airhole is already kind of counter sunk/chamfered (especially if centered in the mortise bottom).Anvil wrote:
If you are trying to eliminate sharp edges for better air flow or to minimize the area for pipe cleaners to catch or to minimize condensation points, should you also countersink the air hole at the bottom of the mortise?
Oh yeah, about the countersink vs. chamfer issue - I believe you are right, it is correctly called chamfer... counter sink refers to a screw head flush with the surface, which is done using a countersink bit, which chamfers the surface for the screw.
A countersink is an internal chamfer of a hole (like when you want to create a relief for a flathead screw so it would be flush with the surface). Knocking the corners off an external feature would be a chamfer. A flat bottomed hole that is concentric with a smaller hole (a mortise for instance) is a counterbore.Anvil wrote:Ahhhh, much better! <hitting head with open hand> Thanks guys. I guess I was confused because I think of a countersink more like what the mortise looks like, as in a flat bottomed hole. I would call that a chamfer but that could just be the terminology I learned working in a small engine factory after college. The pictures are great too BTW.
If you are trying to eliminate sharp edges for better air flow or to minimize the area for pipe cleaners to catch or to minimize condensation points, should you also countersink the air hole at the bottom of the mortise?
All this technical talk is making me dizzy.kkendall wrote:A countersink is an internal chamfer of a hole (like when you want to create a relief for a flathead screw so it would be flush with the surface). Knocking the corners off an external feature would be a chamfer. A flat bottomed hole that is concentric with a smaller hole (a mortise for instance) is a counterbore.Anvil wrote:Ahhhh, much better! <hitting head with open hand> Thanks guys. I guess I was confused because I think of a countersink more like what the mortise looks like, as in a flat bottomed hole. I would call that a chamfer but that could just be the terminology I learned working in a small engine factory after college. The pictures are great too BTW.
If you are trying to eliminate sharp edges for better air flow or to minimize the area for pipe cleaners to catch or to minimize condensation points, should you also countersink the air hole at the bottom of the mortise?
Rad
Just to throw another spanner into the works........... Would it be "politically correct" to drill the mortise with a standard drillbit and then chamfer the outside of the tenon to the same angle as the tip of the drillbit to get a perfect fit or is a flat bottomed hole/mortise with a tenon as Kim illustrated in his pic the standard practice ?
And a question on the countersink. Just how deep should a countersink be ?
The way I see it a depth of more than 0.5mm is kinda overkill. Larger countersink = more turbulence = more space for goo to collect.
And a question on the countersink. Just how deep should a countersink be ?
The way I see it a depth of more than 0.5mm is kinda overkill. Larger countersink = more turbulence = more space for goo to collect.
I chamfer the tenon exterior to match my mortise bit. I like a nice snug tenon-mortise airhole junction. Some say leave a little gap to account for wood swell and tar absorbtion. I don't, but I have had to shave a little tenon off when I noticed a new light gap between stem/shank.
When I have a straight pipe with airhole centered in the mortise, I don't countersink the tenon because it seems counter-intuitive to the whole "no air gap, no turbulence, smooth uninterrupted flow" idea. I've never had pipe fuzz issues. When I make a bent and the airhole is not centered in the bottom of the mortise, I ramp the airhole and slightly countersink the tenon to make sure I have a good pipe cleaner feed, back and forth. I have kind-of noticed that these pipes tend to accumulate condensation slightly more rapidly, but this probably has more to do with the bent stem airway resistance rather than the tenon-mortise airhole junction "gap" turbulence. I don't worry about goo collection though, since I clean my pipes before they taste gooey, which isn't very often really. Perhaps it's more of an issue with aromatic tobacco smokers. Still, it's easy enough to swab a countersunk tenon and mortise bottom.
When I have a straight pipe with airhole centered in the mortise, I don't countersink the tenon because it seems counter-intuitive to the whole "no air gap, no turbulence, smooth uninterrupted flow" idea. I've never had pipe fuzz issues. When I make a bent and the airhole is not centered in the bottom of the mortise, I ramp the airhole and slightly countersink the tenon to make sure I have a good pipe cleaner feed, back and forth. I have kind-of noticed that these pipes tend to accumulate condensation slightly more rapidly, but this probably has more to do with the bent stem airway resistance rather than the tenon-mortise airhole junction "gap" turbulence. I don't worry about goo collection though, since I clean my pipes before they taste gooey, which isn't very often really. Perhaps it's more of an issue with aromatic tobacco smokers. Still, it's easy enough to swab a countersunk tenon and mortise bottom.