I was just looking at the Wood Works episode on the bookcase he built
where the two sides have a bit of a serpentine curve to them.
In that ep, he joined the shelves as well as the top and bottom with
mortise and loose tenon joinery.
First, if you're going to use M&T, why use a loose tenon? It seems
that making and integral tenon in the appropriate place would be
Second, my own choice would be sliding dovetails. Blind of course.
So what do you think? There must be a reason for doing one over the
other, what might that be? Normally he's all over a project with some
incredibily complicated method. I'm waiting for him to introduce some
chinese joinery into his stuff.
BTW, this isn't to knock anyone's methods, it's a matter of being
interested in the "why" of it.
Someone posted an article the other day regarding the degree of pressure
needed to break different joints. The results were surprising to me in that
two and three biscuit joints were very strong and didn't even break at the
joint itself. It also surprised me that the loose tennon actually
outperformed the traditional M&T. However, both of those ranked very high -
I don't remember reading about sliding dovetails.
The test was in the April 2001 FWW #148. The joints were not pulled apart.
M&T tested to be more than twice as strong as double #20 biscuits. The
loose tenons were closer. It does not attempt to say whether a joint is
'strong enough' for a particular application.
I'm interested but I have no way of reading the article or I would. Only
the table of contents is available online. As for the so-called attack, do
you think you provided useful information in your first post?
Now "racking" is good information.
Marks loves his Multi-Router. <g> But apparently, although integral
tenons are more conventional, loose tenon joinery allows choosing a
material for the loose tenon that is stronger than the base material
allowing for greater strength than an integral tenon.
Here is an interesting report you might look over:
FWIW, Form your own conclusions.
P.S. - I found the absence of pocket screw joinery techniques an
interesting omission in this report, however. I would like to have
seen a head-to-head test that included this 'new' joinery method -
although I *really* hate those big holes in the backs of the stiles.
The results of both the dowel and lag screw techniques leads me to the
conclusion that pocket screws are not all they are cracked up to be...
A couple thoughts on pocket hole:
1) It isn't typically used where the screw threads go into end grain, as
was the case with the lag bolts in this experiment. You'd only do that
if you were joining two boards end to end.
2) Pocket holes are mostly used in joints that don't get a lot of sheer
stress. Face frames for cabinets aren't stressed very much. Cabinet
carcasses themselves have compressive stress on the vertical side
plywood, but this doesn't affect the joinery. In my experience, cabinet
joinery failures only seem possible during construction. Once
everything is in place the joinery isn't stressed. This wouldn't be the
case with a joint on something like a door, but then you wouldn't use
pocket hole screws on a door.
Like any other flavor of joinery, it depends upon the application. When it
comes to face frames for cabinets, few other joinery methods rival pocket
hole joinery for speed, appropriate strength for the job, ease of assembly
without clamping and waiting for glue to dry, ability for self squaring with
properly cut parts, and immediate use of the assembly.
A lag bolt has the threads going into end grain while the pocket
hole screw has the threads in edge grain. The flat bottomed
pocket hole and the flat bottom on the screw spread the force
on the end grain over a much larger surface area than just
the thread edges on the lag bolt.
As for why use pocket hole screws when there are so many other
methods of holding two pieces of wood together - well, they are
far more reversible than most other joining methods. That
can mean a little bit more flexability when you're doing a
piece that evolves as you go - something I seem to do often.
Regarding sliding dovetails - they can do what a mortise and
tenon do PLUS they can pull and hold parts together WITHOUT
glue thus allowing for expansion and contraction.
The big advantage of loose tenons is that if you blow making
the loose tenon you're out some time and a few inches of
wood. Blow a "fixed" tenon and you're out the whole part
and the part is seldom just a few inches long.
Now about his choice of joinery being a function of the tools
and equiptment he has available - "I'll do it this way just
because I can" gives rise to a bigger question. Joinery use
to be a way for a craftsman (generic term intended to denote
humans in general and not just the male version of humans)
to show off his hard earned skills, in addition to being
functional. But with all the semi-no brainer machines,
jigs and special fixtures available, anyone with a deep pocket
and marginal eye/hand coordination can make what had been
difficult joints. Does that fact diminish the importance
and value of the true craftsman?
Michael Fortune discribed this dilema. You can design
a piece and then figure out how best to make it,
you can design things based on production methods available.
He feels that the former results in a far greater range of
design options and perhaps better pieces. What do you think?
In some ways it does but I have to tell you, craftsmanship is still
required, even with all the stuff available. A true craftsman will get a
better result than a hack but most people will not know the difference.
I'm talking about fit and finish.
I never cease to be disappointed at the lousy craftsmanship I see
everywhere. My W and I were out at a restaurant last night and the booth
had a plywood back that was coped to fit over some moulding on the wall.
Not only was the coping PATHETIC with gaps exceeding 1/4", but there we
still marks on the wood. It looked like he had used a Sharpie to mark
About a month ago my future brother in law (wife's side) asked for help
building a bar. I show up and he's got a frame built for it. He had
fastened 4x4s to the floor at random distances, twisted 2x4s screwed and
glued across at the top, more 2x4s edge glued and screwed for overhangs,
more. I took one look and felt mind screwed and nauseous. Nothing level,
boards waving at me. I gave him some suggestions (which was all I could
do) and got out of there. I'm getting a headache thinking about it.
Went to their (lives with sis in law) place for the Christmas Eve party,
bar looked fine. He took a few of my suggestions.
Apparently Future B in law was talking shit because wife's brother
starts busting my balls about being too anal and how I like things done
just so. Is this is a bad thing?
Then wife's brother starts some jag about me building cabinets and asks
why I didn't just get Kraftmaid? I say because their junk. He goes off
on another rant how Kraftmaids quality stuff. And on and on ......*
Which brings me to what Bruce wrote: People don't know the difference,
they don't care to know the difference. If it looks pretty it's fine
* This would explain my being an asshole the days around Christmas. A
night with these people and I'm ready for homicide.
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