I've done a lot of "regular" mortise & tenon joints, but am moved to try
loose tenons for my next project (a dining room table). Are there any
situations where loose tenon joinery is NOT recommended? Any hints or
advice?

John B wrote:
I've done a lot of "regular" mortise & tenon joints, but am moved to
try loose tenons for my next project (a dining room table). Are there
any situations where loose tenon joinery is NOT recommended? Any
hints or advice?

The only time I used them was when making a bunch of passage door. Worked
fine.

The mortices were 1/2" x 2" deep in both rails and stiles, cut with a spiral
bit. Duck soup to make the tenons...prepare a long piece to width and
thickness, round over all edges as needed to fit the mortices, cut off a
bunch to correct length. I did make them a tad shorter than the combined
depth of the mortices and cut a shallow groove along one side with a thin
kerf table saw (before rounding over) to provide a place for excess glue to
go.

Only caveat I can think of is to be sure to cut the mortices so that they
are either centered (two passes, one from each side) or offset from the
*correct* side.

--

dadiOH
____________________________

dadiOH's dandies v3.06...
....a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico

John B wrote:
I've done a lot of "regular" mortise & tenon joints, but am moved to try
loose tenons for my next project (a dining room table). Are there any
situations where loose tenon joinery is NOT recommended? Any hints or
advice?

Built a lot of tables and chairs using loose tenon joinery here.

You will find that throughout every test published thus far the
difference between loose and integral tenon joinery is basically
negligible with modern glues.

The big plus with loose tenon, in my experience, is the ability to batch
cut your aprons and rails, thereby gaining a great deal toward the
squareness of your project, as well as the cost effective use of
expensive wood.

IOW, I would not hesitate to continue planning to use loose tenon
joinery on your project.

My tuppence, FWIW ...


--
www.e-woodshop.net
Last update: 10/22/08
KarlC@ (the obvious)

John B wrote:
I've done a lot of "regular" mortise & tenon joints, but am moved to try
loose tenons for my next project (a dining room table). Are there any
situations where loose tenon joinery is NOT recommended? Any hints or
advice?

Loose tenons don't work well in cases where the tenon shoulders would
normally be very thin. Consider a table apron going into a thicker leg.
With a regular tenon you could use a 1/8" shoulder (just enough to
cover any imperfections) to keep the tenon as thick as possible for
strength.

With loose tenons you would be forced to use a thicker shoulder to keep
your mortise walls thick enough. This translates into a thinner tenon,
and possibly a weaker joint.

Chris

Swingman wrote:
Built a lot of tables and chairs using loose tenon joinery here.

You will find that throughout every test published thus far the
difference between loose and integral tenon joinery is basically
negligible with modern glues.


That's true.
In every test I've seen (including one posted here, recently), the wood
fails before the glue.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

Depending on what device (machine\tool) you have to cut the mortises
they can be a real rpoductivity and accuracy help.

However, important consideration is what stress will the joint need to
accomodate. A classic pinned mortise can resist an enormous amount of
twist, pull and down forces and even if the glue fails, after 100
years that mechanical joint of one continuous piece of wood (tenon)
held inside another (mortise) will still have most of it's integrity.

A loose tenon on the other hand, unless it is pinned on both sides
will not have the same longevity and ability to withstand the racking
forces.

Table leg to apron connections take lots of stresses. Chair rail and
spreader connections also. Maybe a picture frame where no stress is
really present or a box where the basic geometry adds to the strength
reauire no second though but structural type connections need to be
closely considered.

On Apr 17, 6:52*am, "John B" wrote:
I've done a lot of "regular" mortise & tenon joints, but am moved to try
loose tenons for my next project (a dining room table). Are there any
situations where loose tenon joinery is NOT recommended? Any hints or
advice?

Chris Friesen wrote:


Loose tenons don't work well in cases where the tenon shoulders would
normally be very thin. Consider a table apron going into a thicker leg.
With a regular tenon you could use a 1/8" shoulder (just enough to
cover any imperfections) to keep the tenon as thick as possible for
strength.

With loose tenons you would be forced to use a thicker shoulder to keep
your mortise walls thick enough. This translates into a thinner tenon,
and possibly a weaker joint.

To the OP ... Chris is correct in that regard, however there is alway a
point where common sense and practicality span the gap of the
theoretical proving of a negative ... use of the traditional "1/3 the
thickness of the rail/apron stock" for tenon thickness and the above
generally becomes a non issue on most projects, loose or integral tenon
notwithstanding.

That said, If you feel you need really thicker tenons for joint
strength, then your project would likely benefit from thicker stock for
your aprons/rails to begin with.

Besides, departing from the ubiquitous "3/4 inch stock" mindset of most
woodworkers today will generally do wonders for your project, in both
looks and durability.


--
www.e-woodshop.net
Last update: 10/22/08
KarlC@ (the obvious)

I agree that loose tenon joints are not really much weaker and
obviously these tests you mention (I haven't seen them) seem to prove
that out but I have seen some 200+ year old windsor chairs that had
proper mechanical fits and they are still going strong. I don'tthink I
could say the same about 200 year old Titebond x but check back in 200
years and maybe my opinion will change.

On Apr 17, 9:37*am, Swingman wrote:
John B wrote:
I've done a lot of "regular" mortise & tenon joints, but am moved to try
loose tenons for my next project (a dining room table). Are there any
situations where loose tenon joinery is NOT recommended? Any hints or
advice?

Built a lot of tables and chairs using loose tenon joinery here.

You will find that throughout every test published thus far the
difference between loose and integral tenon joinery is basically
negligible with modern glues.

The big plus with loose tenon, in my experience, is the ability to batch
cut your aprons and rails, thereby gaining a great deal toward the
squareness of your project, as well as the cost effective use of
expensive wood.

IOW, I would not hesitate to continue planning to use loose tenon
joinery on your project.

My tuppence, FWIW ...

--www.e-woodshop.net
Last update: 10/22/08
KarlC@ (the obvious)

SonomaProducts.com wrote:


A loose tenon on the other hand, unless it is pinned on both sides
will not have the same longevity and ability to withstand the racking
forces.

Cites please ...


--
www.e-woodshop.net
Last update: 10/22/08
KarlC@ (the obvious)

SonomaProducts.com wrote:
I agree that loose tenon joints are not really much weaker and
obviously these tests you mention (I haven't seen them) seem to prove
that out but I have seen some 200+ year old windsor chairs that had
proper mechanical fits and they are still going strong. I don'tthink I
could say the same about 200 year old Titebond x but check back in 200
years and maybe my opinion will change.

Likewise, I have handled some 200 year old pieces containing much
"pocket hole" joinery that is standing the test of time, yet the debate
still rages on that joinery technique ...

Until I see some evidence that loose tenon joinery must be pinned on
both sides in order to stand the test of time, it will remain
conjecture/supposition, without support, in my book.

.... no disrespect intended, you're too damn good of a furniture maker,
and, unlike many of those proffering advice hereabouts, we get to
actually see pictorial evidence that that is so on your website ...



--
www.e-woodshop.net
Last update: 10/22/08
KarlC@ (the obvious)

There are very few down sides... much faster and much
less setup with a proper jig.

The only thing is to watch your reference side. That
can be a slight problem until you screw up a few pieces.

There are MANY jigs out there to do this with...

http://www.shopnotes.com/issues/090/...mortising-jig/

or

http://www.shopnotes.com/issues/088/...tenon-joinery/

my favorite:

http://www.woodsmith.com/issues/147/...he-router-jig/

John B wrote:
I've done a lot of "regular" mortise & tenon joints, but am moved to try
loose tenons for my next project (a dining room table). Are there any
situations where loose tenon joinery is NOT recommended? Any hints or
advice?

Swingman wrote:

To the OP ... Chris is correct in that regard, however there is alway a
point where common sense and practicality span the gap of the
theoretical proving of a negative ... use of the traditional "1/3 the
thickness of the rail/apron stock" for tenon thickness and the above
generally becomes a non issue on most projects, loose or integral tenon
notwithstanding.

My understanding is that the basis of the "1/3 thickness rule" is to
ensure that the mortise sides aren't too thin, so it's actually the
thickness of the piece being mortised that matters, not the piece being
tenoned. If the two pieces are the same, this makes no difference. If
the mortised piece is thicker, this can make a big difference in tenon
thickness.

Of course, this is only important if strength is an issue.

Chris

Swingman wrote:
SonomaProducts.com wrote:


A loose tenon on the other hand, unless it is pinned on both sides
will not have the same longevity and ability to withstand the racking
forces.

Cites please ...

Tough to cite anything related to long-term joint durability. It would
require some realistic form of accelerated aging. Looking at surviving
pieces, we know that pinned joints have lasted a long time. We don't
know how loose tenons hold up over hundreds of years.

All glue fails eventually. This could be accelerated on a wide apron if
the loose tenon is of a species with different expansion rates and
humidity swings are wide.

However, this is stuff that only matters if you're building for the
really long term. And in that case, yellow glue probably isn't the best
choice since it isn't repairable. Hide glue, resorcinol, polyurethane,
epoxy, or plastic resin are all better choices in this respect.

Chris

"Chris Friesen" wrote:

My understanding is that the basis of the "1/3 thickness rule" is to
ensure that the mortise sides aren't too thin, so it's actually the
thickness of the piece being mortised that matters, not the piece
being tenoned. If the two pieces are the same, this makes no
difference. If the mortised piece is thicker, this can make a big
difference in tenon thickness.

SFWIW:

During my time on the design board, it was common practice when
designing a knuckle fitting for a pivot on the end of a cylinder for
example, to make the knuckle twice the width of the pin diameter, thus
insuring that the knuckle had the same cross section in shear as the
pin.

The 1/3 rule for M/T joints in wood is would appear to be based on
similar design concepts.

Lew

However, this is stuff that only matters if you're building for the
really long term. And in that case, yellow glue probably isn't the best
choice since it isn't repairable. Hide glue, resorcinol, polyurethane,
epoxy, or plastic resin are all better choices in this respect.

Chris

I know hide glue is repairable. Are those others?


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

Chris wrote:
Hide glue, resorcinol, polyurethane,
epoxy, or plastic resin are all better choices in this respect.


"-MIKE-" wrote:

I know hide glue is repairable. Are those others?

Long after the wood has returned to compost, epoxy and resorcinol will
still be there, thus what's to repair?

Lew
..

No problem, just spouting opinion.

I have a dirty little secret that I love pocket screws. I've built
many a coffee table and end tables that use them exclusively and I
have every assurance they will stand the test of time. I do also count
on the sort of box truss concept of the geometry to contribute to the
strength of the structure. I did a sort of Federal pencil leg table,
that I still use myself and those pocket screw connections from leg to
apron surely will not last. I am very careful with that little piece
but it looks nice.

On Apr 17, 10:35*am, Swingman wrote:
SonomaProducts.com wrote:
I agree that loose tenon joints are not really much weaker and
obviously these tests you mention (I haven't seen them) seem to prove
that out but I have seen some 200+ year old windsor chairs that had
proper mechanical fits and they are still going strong. I don'tthink I
could say the same about 200 year old Titebond x but check back in 200
years and maybe my opinion will change.

Likewise, I have handled some 200 year old pieces containing much
"pocket hole" joinery that is standing the test of time, yet the debate
still rages on that joinery technique ...

Until I see some evidence that loose tenon joinery must be pinned on
both sides in order to stand the test of time, it will remain
conjecture/supposition, without support, in my book.

... no disrespect intended, you're too damn good of a furniture maker,
and, unlike many of those proffering advice hereabouts, we get to
actually see pictorial evidence that that is so on your website ...



--www.e-woodshop.net
Last update: 10/22/08
KarlC@ (the obvious)

Lew Hodgett wrote:
Chris wrote:
Hide glue, resorcinol, polyurethane,
epoxy, or plastic resin are all better choices in this respect.


"-MIKE-" wrote:

I know hide glue is repairable. Are those others?

Long after the wood has returned to compost, epoxy and resorcinol will
still be there, thus what's to repair?

Lew
.

Ask him, he wrote it.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

Just conjecture considering glue can obviously fail over time.

On Apr 17, 10:27*am, Swingman wrote:
SonomaProducts.com wrote:
A loose tenon on the other hand, unless it is pinned on both sides
will not have the same longevity and ability to withstand the racking
forces.

Cites please ...

--www.e-woodshop.net
Last update: 10/22/08
KarlC@ (the obvious)

-MIKE- wrote:
However, this is stuff that only matters if you're building for the
really long term. And in that case, yellow glue probably isn't the
best choice since it isn't repairable. Hide glue, resorcinol,
polyurethane, epoxy, or plastic resin are all better choices in this
respect.

Chris

I know hide glue is repairable. Are those others?


In my ken, hide glue is the only glue up to this point suitable for
woodworking that will glue/adhere to itself. For a joint to be totally
repairable at some point, as all glue joints will at some point fail, it
helps to be able to dismantle the piece and hide glue is the best bet so
far up to this century.

Epoxy is probably the best bet for longevity, but it is expensive, and
forget about getting anything glued with epoxy apart; and urea
formaldehyde glue may be the second best choice because it is much
cheaper than epoxy, easier to use and because when it does fail, you can
"repair" it, once, with epoxy, for another hundred years.

That said, I'm still using PVA's on most things, and urea formaldehyde
glue (Weldwood, Urac 185 (?), etc) for long open times.


--
www.e-woodshop.net
Last update: 10/22/08
KarlC@ (the obvious)

SonomaProducts.com wrote:
No problem, just spouting opinion.

I have a dirty little secret that I love pocket screws. I've built
many a coffee table and end tables that use them exclusively and I
have every assurance they will stand the test of time. I do also count
on the sort of box truss concept of the geometry to contribute to the
strength of the structure. I did a sort of Federal pencil leg table,
that I still use myself and those pocket screw connections from leg to
apron surely will not last. I am very careful with that little piece
but it looks nice.

Shhhh, not so loud! ....





--
www.e-woodshop.net
Last update: 10/22/08
KarlC@ (the obvious)

-MIKE- wrote:
However, this is stuff that only matters if you're building for the
really long term. And in that case, yellow glue probably isn't the best
choice since it isn't repairable. Hide glue, resorcinol, polyurethane,
epoxy, or plastic resin are all better choices in this respect.

Chris

I know hide glue is repairable. Are those others?

According to Bob Smalser
(http://www.sawmillcreek.org/showthread.php?t=21822) the others are
repairable with epoxy. No data on whether they are repairable with
themselves.

Chris

Chris Friesen wrote:
-MIKE- wrote:
However, this is stuff that only matters if you're building for the
really long term. And in that case, yellow glue probably isn't the
best choice since it isn't repairable. Hide glue, resorcinol,
polyurethane, epoxy, or plastic resin are all better choices in this
respect.

Chris

I know hide glue is repairable. Are those others?

According to Bob Smalser
(http://www.sawmillcreek.org/showthread.php?t=21822) the others are
repairable with epoxy. No data on whether they are repairable with
themselves.

Chris

Thanks for that info.
Does that mean that epoxy melts into them or reactivates them in some way?
Or just because epoxy will adhere to plastic?


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

Lew Hodgett wrote:

Long after the wood has returned to compost, epoxy and resorcinol will
still be there, thus what's to repair?

Epoxy degrades with heat and UV. In either case, under humidity cycling
I could see the layer of wood immediately next to the glue failing.

Chris

"Swingman" wrote:

Epoxy is probably the best bet for longevity, but it is expensive,
and forget about getting anything glued with epoxy apart; and urea
formaldehyde glue may be the second best choice because it is much
cheaper than epoxy, easier to use and because when it does fail, you
can "repair" it, once, with epoxy, for another hundred years.

"Expensive" is a relative term.

Last time I bought a gallon of TB-II it was about $20.

I don't pay even close to $20/gal for epoxy, but then I buy it in 500
lb (55 gal) drums.

Retail, a gallon of epoxy is probably about $60 these days.

Somehow, I think the cost of the adhesives used in a project gets lost
when compared to the cost of any of the following:

1) Wood
2) Finishing materials
3) Hardware.

BTW, slow hardener and laminating epoxy resin will give at least 30
minute open time @ 75F which is a whole lot more than TB-II.

Lew

"Chris Friesen" wrote:

Epoxy degrades with heat and UV. In either case, under humidity
cycling

I could see the layer of wood immediately next to the glue failing.

As I said, " Long after the wood has returned to compost, epoxy and
resorcinol will
still be there, thus what's to repair?, and that includes the
conditions described above

As for heat degradation, by the time the epoxy is softened, the wood
will be scorched.

If you are going to use epoxy as a coating, then UV protection is
required.

If you are going to use epoxy as an adhesive, no UV protection req'd
since only the outside edges of the joints are exposed.

Lew

Lew Hodgett wrote:
"Swingman" wrote:

Epoxy is probably the best bet for longevity, but it is expensive,

"Expensive" is a relative term.

Last time I bought a gallon of TB-II it was about $20.

Retail, a gallon of epoxy is probably about $60 these days.

IOW, 3 times the price, and much more in smaller quantities ... nuff
said.

"Swingman" wrote:


IOW, 3 times the price, and much more in smaller quantities ... nuff
said.


3 times the price for equal quantities: however, 3 times a small total
cost percentage is still a small total cost percentage.

Nuf saidgrin

Lew

"John B" wrote in message
...
I've done a lot of "regular" mortise & tenon joints, but am moved to try
loose tenons for my next project (a dining room table). Are there any
situations where loose tenon joinery is NOT recommended? Any hints or
advice?


Advise, LOL. IMHO the more mortise and tennon joints you use the stronger
the project joints will be. The easier it is to create loose mortise and
tennon joints the more you will use them.

Buy a Domino NOW!

-MIKE- wrote:
Chris Friesen wrote:

According to Bob Smalser
(http://www.sawmillcreek.org/showthread.php?t=21822) the others are
repairable with epoxy. No data on whether they are repairable with
themselves.

Does that mean that epoxy melts into them or reactivates them in some way?
Or just because epoxy will adhere to plastic?

Just that epoxy will adhere to the previous glue. And it's gap-filling,
which helps if the previous joint members have been deformed slightly.

Chris

"Upscale" wrote in message
...

"Leon" wrote in message
Buy a Domino NOW!

Well, considering how much you've used yours lately, you must be getting
really sick and tired of it. So, I'll help you out and offer you $100 for
yours including the vacuum. Hell, I'll even pay the shipping to me up here
in Canada.


Wow! you missed my sell point by $25. LOL

"Leon" wrote in message
Buy a Domino NOW!

Well, considering how much you've used yours lately, you must be getting
really sick and tired of it. So, I'll help you out and offer you $100 for
yours including the vacuum. Hell, I'll even pay the shipping to me up here
in Canada.

Subject

Think biscuits.

Lew

I don't pay even close to $20/gal for epoxy, but then I buy it in 500 lb
(55 gal) drums.

Retail, a gallon of epoxy is probably about $60 these days.


Where do you get retail pricing like that?

As a point of reference Lee valley sells epoxy for about $40/quart


http://www.leevalley.com/wood/page.a...at=1,110,42965

-Steve

C & S wrote:
I don't pay even close to $20/gal for epoxy, but then I buy it in
500 lb (55 gal) drums.

Retail, a gallon of epoxy is probably about $60 these days.


Where do you get retail pricing like that?

Here, for one...
http://www.uscomposites.com/epoxy.html


--

dadiOH
____________________________

dadiOH's dandies v3.06...
....a help file of info about MP3s, recording from
LP/cassette and tips & tricks on this and that.
Get it at http://mysite.verizon.net/xico

"C & S" wrote:

Where do you get retail pricing like that?

Almost anybody who is in the epoxy business.

Try System3 for example.

As a point of reference Lee valley sells epoxy for about $40/quart

Obviously not in the epoxy business.

Lew

On Fri, 17 Apr 2009 12:27:09 -0500, the infamous Swingman
scrawled the following:

SonomaProducts.com wrote:


A loose tenon on the other hand, unless it is pinned on both sides
will not have the same longevity and ability to withstand the racking
forces.

Cites please ...

I wish I still had that link I saw eons ago. It had a video of all the
joint types (dowel, loose tenon, biscuit, integral m&t, lap, miter,
etc.) being tested with strength charts afterward.

Here's one newer destructive test site:
http://www.dowelmax.com/jointstrength.html (totally bogus, IMHO)

http://www.youtube.com/watch?v=DhLfb7m9Fug Much more scientific. I
wish they had shown the data for pinned (but not glued) m&t joints.


As usual, a lot of variation comes from loose fit, so remember to fit
your tenons (loose or integral) snugly for the best durability.

------
We're born hungry, wet, 'n naked, and it gets worse from there.