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Dear PipeGods --

Not smart assery, but an honest question:

There is ZERO advantage in terms of labor, tools, or materials in making a mortise & tenon smaller than what's correct for a pipe, so WHY do so many of the Scand guys do it?

I've lost count of the number of these I've fixed over the years. This one is Bang'$ top grade minus one click (B), weighs 80 grams, and had a Dunhill Group 1-sized tenon. Unreinforced. Big surprise that it let go only days into its smoking life. Not.

There's no doubt they're aware of it, too, because they get pinged routinely when it happens. Then they say, "We don't do repairs."

Confusedly Yours,

le Moi

That's job security for you, my friend.

Except I HATE that particular task with a vengeance. Endlessly fussy, and unforgiving in the extreme. Plus, the work-holding requirements can be nuts. (Take the above example: how would you clamp/immobilize that stem without marring it, while maintaining perfect axial alignment AND be adjustable side-to-side + back-and-forth?)

Remember, no do-overs.

The only possible reason I could think of would be that then the tenon, not the shank is the weakest link. But even then, 1/4" integral tenons seem like they'd be too flimsy no matter what. If I have to go that thin, I prefer the strength of delrin.

I am curious how you manage workholding for a tenon replacement on a tapered stem like that.

Perhaps the reasoning could be that minuscule tenons allow more real estate for those polished shank faces?

sandahlpipe wrote: I am curious how you manage workholding for a tenon replacement on a tapered stem like that.

Ratimus wrote:Perhaps the reasoning could be that minuscule tenons allow more real estate for those polished shank faces?

What was I thinking? OF COURSE that's it! (now I feel like an idjit)

Are they always exactly the same size? Maybe it's a consistency thing.

99% of my pipes have a 6mm tenon.

caskwith wrote:Are they always exactly the same size? Maybe it's a consistency thing.

99% of my pipes have a 6mm tenon.

. 23"

Possibilities:

A) You're actually from Daneland and are only pretending to be English

B) You reinforce them with a tube/sleeve

C) 95% of the peeps you make are teeny weenie

D) You're pulling my chain

I have been using 6mm acetal tenons for almost 10 years, never had a tenon break and since I started threading them I have never had a tenon pull out either. No tube or reinforcement. I make some small pipes but I have used them even on magnum/mini mag sized pipes as well. Probably 80% of my pipes are a group 3-4.

Is "acetal" Britspeak for Delrin?

If so, that would explain not breaking.

On a magnum-sized pipe, though? It's also quite flexible.

LatakiaLover wrote:Is "acetal" Britspeak for Delrin?

If so, that would explain not breaking.

On a magnum-sized pipe, though? It's also quite flexible.

Delrin was a DuPont trademark. It has pretty much become a generic term as there are now many different manufacturers since DuPont invented it in '53.
Acetal comes in part from its chemical makeup (think acetic acid). Back in the day when I had an injection molding machine the crap would run everyone out of the shop from the fumes it gives off when it's hot. Big use over the years has been for internal parts in washer-less faucets.

Delrin is a branded version of acetal (with it's own properties). The stuff I buy is slightly harder than standard delrin, machines better and isn't so slippery. I found some issues using delrin that were solved by switching to acetal. It also happens to take glue a little better, though that doesn't matter for me since my tenons are threaded anyway.

I have not found it to be a problem on large pipes, yes there is flex in the tenon as you would expect, but when you have a large shank face this gives it all the stability it needs. In fact any size shank face down to about 12mm gives it plenty of support when pushed all the way in. Under 12mm I switch to using 4mm stainless tubing as reverse tenons anyway.

There is really only one time where using 6mm tenons causes me an issue, heavily bent shapes like an Oom Paul. I have had to use a large tenon at times for those pipes, but I make them so rarely it's not really a problem.

Of course this is really just a personal preference thing, I am not touting 6mm tenons to be superior, I just wanted to standardise my tenons as much as possible and I chose 6mm because it worked well for me and was small enough that it let me safely make shanks down to 12mm even on Morta.

LatakiaLover wrote:

sandahlpipe wrote: I am curious how you manage workholding for a tenon replacement on a tapered stem like that.

I know how he does it. But I was sworn to secrecy before he let me into his shop for the first time. It was one of those old school Masonic Lodge ritual type deals too....I'm bound by blood