Cuyler,
 
If you refocus your building detective goggles you will be able to see the
carpenter working at laying out those tenons before he cut them (or someone
did). The fact that a 2" tenon on a 6" timber is "centered" is just
coinkydink. Log builders and Chinese carpenters work to "centers" but timber
framers who work with squared up stock work to a "face". Historically it was
referred to as the "fair face" or the "upper face" (explained in my booklet
which you will have access to soon) and more modern terms are "layout face"
or "reference face". Joinery was laid out from that face using a framing
square which has a 2" body and a 1 1/2" tongue even today. The reason that
is what size framing squres are is called the "joiners language" which means
you locate mortices and tenons by setting them off by the width of the body
or tongue of the square from the reference face and they are sized to match
either the body or tongue as well. So the joiner's language would place the
mortices and tenons at 2" to 2" (which I place on drawings as 2"<>2") or 1
1/2" to 1 1/2". In some cases like major tie beams it might be 2" to 3" but
it always matches the square.
 
The beauty (simplicity) of all this is not only that you can layout joinery
with a square and an awl but you can also gauge it that way. If the tenon
matches the body or tongue of the square and in turn that part of the square
fits into the mortice then everything fits. The square doesn't even have to
be accurate (old ones often weren't) as long as the same square (the
master's) is used to gauge all the joinery.
 
My experience is that joinery in the New World in the 17th and 18th century
was most often laid out 2"<>2". "Stub" tenons (those meant to act as
locaters but not to be pegged) were 2"<>2"x2" (2" long) and those that were
meant to be pegged were 2"<>2"x4" so that everything could be easily laid
out with the body of the square.
 
TMI?
 
Rudy

  _____  

From: plz practice conservation of histo presto eye blinks
[mailto:[log in to unmask]] On Behalf Of Cuyler Page
Sent: Tuesday, January 08, 2008 4:19 PM
To: [log in to unmask]
Subject: Re: [BP] Speaking the Lingo


As a Heritage Interpretation hands-on demonstration exhibit at the historic
site, I am about to embark on a large scale "piece-en-piece" or
"piece-sur-piece" model of the original 1850's Hudson's Bay Company
Craigflower Farmhouse in Victoria, BC.   Does anyone know the typical size
and proportion for the tenons or mortises for this type of construction?
The original building is still intact, and the walls covered with rough-sawn
clapboard siding (also original) (there must be an interesting story behind
the combination) so I can not get a measurement off the originals to see the
dimensions for the post tenons or the wall slots and wall log tenons.
There are no other surviving examples of this construction within knowledge
distance.
 
The broad axe squared posts are 6" x 12" and the wall logs, axe-squared on
the open face sides but not the top and bottom, are 6" thick and random
widths (heights).   The wall tenons appear 2" thick or 1/3 the wall
thickness but I do not know how long, or how deep are the post slots.
 
I imagine a 2" long wall tenon would do the job, and maybe 2" or 3" tenons
for the post tops and bottoms, but I also read from modern commercial log
builder promotional material of pegging the post tops to the capping log and
sill timber, and that means a much longer tenon.   Perhaps that idea of
pegging is a modern Building Code fear factor.
 
All comments welcomed, and thanks in advance.
 
Cuyler in BC
 
 
 

 


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