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21/10/2006 10:27 PM

Plywood tenon?

Can I use a piece of 1/4" plywood as a tenon for joints in solid wood?
Or will the fact that the plywood doesn't expand/contract like solid
wood cause the joint to crack?

TIA,
Phil


This topic has 12 replies

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"Andy Dingley "

in reply to [email protected] on 21/10/2006 10:27 PM

23/10/2006 6:14 AM


[email protected] wrote:

> Can I use a piece of 1/4" plywood as a tenon for joints in solid wood?

Yes. If you're working at 1/4" or thinner, then the best way to make an
accurate tenon this thin might well be to use ready-thicknessed
plywood.

I wouldn't recommend it for big carpentry, but it's a fair compromise
technique for thin splines.

cb

charlie b

in reply to [email protected] on 21/10/2006 10:27 PM

22/10/2006 2:16 AM

[email protected] wrote:
>
> Can I use a piece of 1/4" plywood as a tenon for joints in solid wood?

yes

> Or will the fact that the plywood doesn't expand/contract like solid
> wood cause the joint to crack?

no

> TIA,
> Phil

charlie b

Cc

"Charley"

in reply to [email protected] on 21/10/2006 10:27 PM

23/10/2006 2:12 AM

Plywood will work OK as a loose tenon, but you will have an even stronger
joint if you use a solid piece of wood with it's grain oriented across the
joint. You can't achieve this with plywood

--
Charley

<[email protected]> wrote in message
news:[email protected]...
> Can I use a piece of 1/4" plywood as a tenon for joints in solid wood?
> Or will the fact that the plywood doesn't expand/contract like solid
> wood cause the joint to crack?
>
> TIA,
> Phil
>

JJ

in reply to "Charley" on 23/10/2006 2:12 AM

23/10/2006 7:10 AM

Mon, Oct 23, 2006, 2:12am (EDT+4) [email protected] (Charley) doth
stateth:
Plywood will work OK as a loose tenon, but you will have an even
stronger joint if you use a solid piece of wood with it's grain oriented
across the joint. You can't achieve this with plywood

You've lost me on that one. How about explaining just whatcha
mean?



JOAT
It's not hard, if you get your mind right.
- Granny Weatherwax

JC

"J. Clarke"

in reply to "Charley" on 23/10/2006 2:12 AM

23/10/2006 10:03 AM


"J T" <[email protected]> wrote in message
news:[email protected]...
> Mon, Oct 23, 2006, 2:12am (EDT+4) [email protected] (Charley) doth
> stateth:
> Plywood will work OK as a loose tenon, but you will have an even
> stronger joint if you use a solid piece of wood with it's grain oriented
> across the joint. You can't achieve this with plywood
>
> You've lost me on that one. How about explaining just whatcha
> mean?

Solid wood has all the grain oriented the same direction, plywood has half
of it (more or less) oriented perpendicular to the rest. In a tenon the
major loading is going to be shear across the grain of solid wood--half of
the wood in plywood is oriented in a direction that provides little strength
in that direction.

Further, leaving aside the difficulties of glueing such woods, you can make
a loose tenon out of Ipe or Lignum Vitae and it will be vastly stronger when
loaded in shear across the grain than will birch or douglas fir.

f

in reply to "J. Clarke" on 23/10/2006 10:03 AM

24/10/2006 8:56 AM


J T wrote:
> Mon, Oct 23, 2006, 10:03am [email protected] (J. Clarke) doth
> sayeth:
> Solid wood has all the grain oriented the same direction, plywood has
> half of it (more or less) oriented perpendicular to the rest. <snip>
>
> Yep, already know that. But, I would be thinking that the joint
> would destruct before the strength of the tenon counted, especially if
> the tenon is only 1/4"
>

Huh?

Isn't it the tenon that holds the joint together?

Otherwise, why use a tenon?

--

FF

PD

"Paul D"

in reply to [email protected] on 24/10/2006 8:56 AM

26/10/2006 11:59 PM

Stick with dowels ..... small round loose tennons
"J T" <[email protected]> wrote in message
news:[email protected]...
> Tue, Oct 24, 2006, 8:56am (EDT-3) [email protected] doth query:
> Huh?
> Isn't it the tenon that holds the joint together?
> Otherwise, why use a tenon?
>
> Durned if I know, anymore I'm just confused by ll it all. I think
> I'll just stick with dowels.
>
>
>
> JOAT
> It's not hard, if you get your mind right.
> - Granny Weatherwax
>

PD

"Paul D"

in reply to "Paul D" on 26/10/2006 11:59 PM

29/10/2006 9:09 PM

THe term 'loose' was used loosley

"J T" <[email protected]> wrote in message
news:[email protected]...
Thu, Oct 26, 2006, 11:59pm (EDT+14) [email protected] (Paul D) doth
sayeth:
Stick with dowels ..... small round loose tennons

Not loose the way I use 'em.



JOAT
It's not hard, if you get your mind right.
- Granny Weatherwax

JJ

in reply to "Paul D" on 26/10/2006 11:59 PM

26/10/2006 10:39 AM

Thu, Oct 26, 2006, 11:59pm (EDT+14) [email protected] (Paul=A0D) doth
sayeth:
Stick with dowels ..... small round loose tennons

Not loose the way I use 'em.



JOAT
It's not hard, if you get your mind right.
- Granny Weatherwax

JJ

in reply to [email protected] on 24/10/2006 8:56 AM

25/10/2006 3:23 PM

Tue, Oct 24, 2006, 8:56am (EDT-3) [email protected] doth query:
Huh?
Isn't it the tenon that holds the joint together?
Otherwise, why use a tenon?

Durned if I know, anymore I'm just confused by ll it all. I think
I'll just stick with dowels.



JOAT
It's not hard, if you get your mind right.
- Granny Weatherwax

JJ

in reply to "J. Clarke" on 23/10/2006 10:03 AM

24/10/2006 9:07 AM

Mon, Oct 23, 2006, 10:03am [email protected] (J.=A0Clarke) doth
sayeth:
Solid wood has all the grain oriented the same direction, plywood has
half of it (more or less) oriented perpendicular to the rest. <snip>

Yep, already know that. But, I would be thinking that the joint
would destruct before the strength of the tenon counted, especially if
the tenon is only 1/4"



JOAT
It's not hard, if you get your mind right.
- Granny Weatherwax

BA

B A R R Y

in reply to [email protected] on 21/10/2006 10:27 PM

22/10/2006 1:15 PM

On 21 Oct 2006 22:27:51 -0700, [email protected] wrote:

>Can I use a piece of 1/4" plywood as a tenon for joints in solid wood?

Yes, and it makes good "splines" too. A spline is kind of a long,
shallow tenon inserted into grooves on both sides.

>Or will the fact that the plywood doesn't expand/contract like solid
>wood cause the joint to crack?

Most woods don't move enough to make that an issue in the case of a
typical 1-2" long tenon.

Don't forget when making your mortises that 1/4" plywood isn't really
1/4" thick!


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