Pardon the repost... it's been 24 hours and it still has not shown up:
I am wrapping up a bedroom remodel and have yet to build the passage and two
closet doors. I am building rather than buying because I would like them to
match the rest of the (1860 vintage) house.
These are four (flat) panel doors with a simple shaker-like bevel
surrounding each panel. The center and lower rails are about 8-inches wide.
The center rail meets the stiles with a twin through tennon rather than a
single tennon.
I have always designed wide rails with a single tennon, pinned in the center
with unglued "stubs" that sit in the panel groove to mitigate any potential
cup or twist.
While I suspect that the wider stance of twin tennons would do a better job
of controlling overall wracking of the door frame, I would think that the
crossgrain implications would not fare much better than a single full width
tennon. That is, shrinkage could cause the center rail to split.
Is there some other compelling reason to use a twin-tennon design? And does
the availability of modern glues change what makes sense today vs. the
original design?
Segue into question 2: Should I avoid regular yellow glue because of
"creep"? The door, being constructed of ash will be fairly heavy and enjoy
significant racking forces from gravity. The through tennons will be pinned,
so perhaps it just doesn't matter.
Thanks,
Steve
** Posted from http://www.teranews.com **
"StephenM" wrote
> If I understand correctly, make the point that the mechanics of the
double
> tennon joint is what provides strength. Would a single-tennon joint (of
> equivalent aggregate tennon size) not be nearly as strong without the
> "captured" cross-grain geometry which might be prone to splitting?
What dpb said ...
In addition, David Marks has a large door project, on DIY website IIRC, that
you may want to look at, as well as Norm's door project, but I would look at
the joinery DJM uses with a critical eye.
Mr. Marks has professed an ignorance of traditional joinery in his younger
days in the past, and in the joinery he used on this particular project,
IIRC, was loose tenon joinery and I don't recall him using double tenons on
the lock or kick rail ... I could be wrong about that, but it would be worth
checking out if you can get a copy of that episode.
While I'm a big fan of loose tenon joinery (I own a Multi-router that is
used strictly for that purpose), I'm not too sure I would be completely
comfortable using single loose tenons on a large door, particularly on the
two traditionally wider rails (lock and kick), and without a haunch ...
probably wouldn't be all that concerned with strength double loose tenons as
much as the lack of the haunch in between which logically, and in practice,
seems a bit of extra help in mitigating warpage of the wider rails over the
long haul.
Don't want to sound preachy, but nothing wrong with a belt and suspenders
approach on doors as warp/bow in any door component, regardless of the size,
is eventual hell to pay, so do what you can to mitigate as much as you can
with your joinery, as well as taking extra care in selection, milling and
acclimating your stock before assembly ... IME, the latter is just as
critical as the former.
--
www.e-woodshop.net
Last update: 5/14/08
KarlC@ (the obvious)
"StephenM" <[email protected]> wrote in message
news:[email protected]...
>
> Pardon the repost... it's been 24 hours and it still has not shown up:
>
>
> I am wrapping up a bedroom remodel and have yet to build the passage and
> two
> closet doors. I am building rather than buying because I would like them
> to
> match the rest of the (1860 vintage) house.
>
> These are four (flat) panel doors with a simple shaker-like bevel
> surrounding each panel. The center and lower rails are about 8-inches
> wide.
> The center rail meets the stiles with a twin through tennon rather than a
> single tennon.
>
> I have always designed wide rails with a single tennon, pinned in the
> center
> with unglued "stubs" that sit in the panel groove to mitigate any
> potential
> cup or twist.
>
> While I suspect that the wider stance of twin tennons would do a better
> job
> of controlling overall wracking of the door frame, I would think that the
> crossgrain implications would not fare much better than a single full
> width
> tennon. That is, shrinkage could cause the center rail to split.
>
> Is there some other compelling reason to use a twin-tennon design? And
> does
> the availability of modern glues change what makes sense today vs. the
> original design?
>
> Segue into question 2: Should I avoid regular yellow glue because of
> "creep"? The door, being constructed of ash will be fairly heavy and enjoy
> significant racking forces from gravity. The through tennons will be
> pinned,
> so perhaps it just doesn't matter.
>
> Thanks,
>
> Steve
>
>
>
> ** Posted from http://www.teranews.com **
I have worked a lot with ash. On a solid ash door of 18 inches wide it
will expand 1/4"+ between winter and summer.
So allowing for expansion is a must. As for glues I have used in the past
yellow carpenters type with fair results.
Now I only use the exterior glues made by Lepage and Titebond lll or better
for ref. see
http://www.titebond.com/IntroPageTB.ASP?UserType=1&ProdSel=ProductCategoryTB.asp?prodcat=1
These glues are good but when subject to stress they have to be used with
mechanical fastening devices like screws or joineries. Good luck.
Denis M, Rothesay NB
1
"Swingman" <[email protected]> wrote in message
news:[email protected]...
> "StephenM" wrote
>
>> Is there some other compelling reason to use a twin-tennon design? And
> does
>> the availability of modern glues change what makes sense today vs. the
>> original design?
>
> Actually, what you want are "double" tenons, not "twin" tenons, in joinery
> parlance.
>
> (twin tenons being side by side within the thickness of the rail).
>
I never really thought about the distinction. Good point.
> Glue was never the reason for using double tenons, particularly on the
> lock
> and kick rails of a large door frame, it's the mechanical strength of the
> joinery itself that has stood the test of time in door making,
> irrespective
> of the glue used. So, yes', there is a compelling reason to use a "double
> tenon" design, at the very least on the lock rail.
If I understand correctly, make the point that the mechanics of the double
tennon joint is what provides strength. Would a single-tennon joint (of
equivalent aggregate tennon size) not be nearly as strong without the
"captured" cross-grain geometry which might be prone to splitting?
** Posted from http://www.teranews.com **
"StephenM" wrote
> Is there some other compelling reason to use a twin-tennon design? And
does
> the availability of modern glues change what makes sense today vs. the
> original design?
Actually, what you want are "double" tenons, not "twin" tenons, in joinery
parlance.
(twin tenons being side by side within the thickness of the rail).
Glue was never the reason for using double tenons, particularly on the lock
and kick rails of a large door frame, it's the mechanical strength of the
joinery itself that has stood the test of time in door making, irrespective
of the glue used. So, yes', there is a compelling reason to use a "double
tenon" design, at the very least on the lock rail.
While you're at it, a good practice is to also use a haunch between the
double tenons (in rail width: 1/3rd tenon-1/3rd haunch-1/3rd tenon), which
will help prevent the rail(s) from warping.
--
www.e-woodshop.net
Last update: 5/14/08
KarlC@ (the obvious)
On Jul 11, 9:44 am, dpb <[email protected]> wrote:
> StephenM wrote:
>
> ...> If I understand correctly, make the point that the mechanics of the double
> > tennon joint is what provides strength. Would a single-tennon joint (of
> > equivalent aggregate tennon size) not be nearly as strong without the
> > "captured" cross-grain geometry which might be prone to splitting?
>
> ...
>
> quibble..."tenon" is only two "n's" total, not three...end quibble
>
> If a single tenon of the same aggregate size were used instead, the
> distance from the top to the bottom would be less than that same
> distance from the top of the top to the bottom of the bottom double
> tenon. Hence the moment arm of the double resisting wracking is larger
> than the equivalently-sized single. This, combined w/ the noted grain
> orientation is advantage of the double.
>
> --
Does anyone have any book recommendations or links to share for door
building? One of my dream projects is to build new doors for my house.
Nothing fancy, just frame and panel type based on another house from
the same timeframe (~1960s). I want to do a good job, but I can't find
much to help me out.
Plus, it just wouldn't be right for me to go visit my grandmother in
law and ask to break apart one of her doors to see how it was built. I
don't think the family would like that at all. :-)
Thanks,
Nathan
StephenM wrote:
...
> If I understand correctly, make the point that the mechanics of the double
> tennon joint is what provides strength. Would a single-tennon joint (of
> equivalent aggregate tennon size) not be nearly as strong without the
> "captured" cross-grain geometry which might be prone to splitting?
...
quibble..."tenon" is only two "n's" total, not three...end quibble
If a single tenon of the same aggregate size were used instead, the
distance from the top to the bottom would be less than that same
distance from the top of the top to the bottom of the bottom double
tenon. Hence the moment arm of the double resisting wracking is larger
than the equivalently-sized single. This, combined w/ the noted grain
orientation is advantage of the double.
--
N Hurst wrote:
...
> Does anyone have any book recommendations or links to share for door
> building? One of my dream projects is to build new doors for my house.
> Nothing fancy, just frame and panel type based on another house from
> the same timeframe (~1960s). I want to do a good job, but I can't find
> much to help me out.
...
Didn't look for the specific link but there have been two or three
articles within last few years at the outside in FWW and/or FHB.
My favorite "how to" was a reprint Delta used to include w/ their
spindle shapers but it, unfortunately, is now out of print and no longer
available. My copy got smudged enough as to make it an unsuitable
candidate for scanning or I'd post it somewhere.
There's a book on architectural woodworking also published by Taunton
press I know--I don't recall who was the author but I've never seen
anything by them that wasn't at least adequate. If you have a decent
public library, I'd think there would be a section there that would have
something--I don't have anything specific in my library, sorry; I rely
on the Delta sheet referred to above so don't have a specific reference.
I remember a text from a college shop course I took as an elective
that I was to cheap/broke to keep but don't even remember the author.
The biggest difference between current practice and older is the
tendency towards the stub tenon and dowels in commercial doors and
windows as opposed to the older full through or tenon. To cope the
matching mold on the door required a stub spindle cutter which is very
difficult to find any more (in fact, I don't know of any generally
available any longer since Delta quit making theirs outside the
commercial manufacturers) other than the stub router bit set from CMT.
To make the cut now is typically done by mitering the sticking instead
outside the factory setting.
--
--
Swingman wrote:
...
What he said... :)
> with your joinery, as well as taking extra care in selection, ...
Only add that in selection, species is important particularly for
exterior doors; you can get away w/ most anything interior if going
exotic.
And to add, in selection quarter- or near-quarter-sawn stock is
preferable as it will provide the most stable dimensional material you
can obtain of a given species outside composites.
I'd not feel uncomfortable at all w/ the loose tenons on interior doors
although I certainly don't disagree w/ the logic on the haunch. On
exterior, I'd feel far more "iffy" and wouldn't dispense I don't
believe; certainly not on anything over a 2-0.
In the end, despite the heft (a 7-ft 2x8 lock stile blank is pretty good
chunk), door and window making is a very enjoyable task imo(*). One
thing almost required imo to do it with any speed is a minimum 60+"
jointer table--anything less is a real hassle.
Enjoy!!! :)
(*) If I were in a more populated place where there were enough demand,
my "retirement" job would be to open a small, custom architectural
millworks...
--