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05/05/2007 7:15 PM

Butt Joint strength

The project I'm working on requires a butt joint that will undergo a little
stress. I'm obviously going the glue the length of the joint, but I'd like
to reinforce it with a)screws, b)dowels, or c)biscuits. Anyone have an
opinion as to which of these 3 would add the most strength to the joint?


This topic has 16 replies

nn

in reply to [email protected] on 05/05/2007 7:15 PM

05/05/2007 12:55 PM

On May 5, 2:15 pm, [email protected] wrote:
> The project I'm working on requires a butt joint that will undergo a little
> stress. I'm obviously going the glue the length of the joint, but I'd like
> to reinforce it with a)screws, b)dowels, or c)biscuits. Anyone have an
> opinion as to which of these 3 would add the most strength to the joint?

OOHHHH Charlie beeeee......

Where are you?

;^)

Robert

FH

Father Haskell

in reply to [email protected] on 05/05/2007 7:15 PM

05/05/2007 5:12 PM

On May 5, 3:15 pm, [email protected] wrote:
> The project I'm working on requires a butt joint that will undergo a little
> stress. I'm obviously going the glue the length of the joint, but I'd like
> to reinforce it with a)screws, b)dowels, or c)biscuits. Anyone have an
> opinion as to which of these 3 would add the most strength to the joint?

Square dowels, aka false tenons.

Bb

"Bob"

in reply to [email protected] on 05/05/2007 7:15 PM

05/05/2007 5:34 PM


<[email protected]> wrote in message news:TI4%[email protected]...
> The project I'm working on requires a butt joint that will undergo a
> little
> stress. I'm obviously going the glue the length of the joint, but I'd like
> to reinforce it with a)screws, b)dowels, or c)biscuits. Anyone have an
> opinion as to which of these 3 would add the most strength to the joint?

Of those choices, dowels unquestionably.

Bb

"Bob"

in reply to [email protected] on 05/05/2007 7:15 PM

07/05/2007 9:20 AM


<[email protected]> wrote in message news:IDn%[email protected]...
> Thanks for the responses. I'm leaning towards dowels. To explain the
> project
> further, it's a fold over leg for a Murphy bed. As such, the leg itself
> (and
> the joint) is situated in the middle of the second piece which negates the
> possibility of using a scarf or half-lap joint. A stopped dado is a
> possibility, as long as I increase that dimension of the foot to
> compensate
> for the depth of the dado.

I use dowels for virtually everything since I got a dowelmax jig. It
doesn't have the production speed of a domino, but it secures the joint in
all directions (not just two dimensions) and it doesn't require a $300
vacuum to use it. :-)

Bob

MD

"Morris Dovey"

in reply to [email protected] on 05/05/2007 7:15 PM

05/05/2007 3:11 PM

[email protected] wrote:
| The project I'm working on requires a butt joint that will undergo
| a little stress. I'm obviously going the glue the length of the
| joint, but I'd like to reinforce it with a)screws, b)dowels, or
| c)biscuits. Anyone have an opinion as to which of these 3 would add
| the most strength to the joint?

How many opinions can you stand? :-D

For me, the answer would depend on the stresses involved and what the
cosmetic requirements are. I'm prone to use pocket screw joinery when
I can - and M&T (sometimes pegged) when I can't.

Worse still, if I feel particularly AR about racking, I use a joint
like the one pictured at the link below.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/design.html

m

in reply to [email protected] on 05/05/2007 7:15 PM

06/05/2007 10:44 AM

To answer your question where the butt joint is not subject to stress and
blended for cosmetic effect the screw and dowel construction are the most
effective. Where the joint is subjected to minimum to stronger stress, as
stated before, "Consider a scarf, finger or lap joint". If you are dealing
with oily wood like teak even two part epoxy will not adhere good you have
to add mechanical devices like screws or equivalent.

"Phisherman" <[email protected]> wrote in message
news:[email protected]...
> On Sat, 5 May 2007 19:15:04 GMT, [email protected] wrote:
>
>>The project I'm working on requires a butt joint that will undergo a
>>little
>>stress. I'm obviously going the glue the length of the joint, but I'd like
>>to reinforce it with a)screws, b)dowels, or c)biscuits. Anyone have an
>>opinion as to which of these 3 would add the most strength to the joint?
>
>
> Butt joints are the weakest. Consider a scarf, finger or lap joint.

EP

"Edwin Pawlowski"

in reply to [email protected] on 05/05/2007 7:15 PM

05/05/2007 9:44 PM


<[email protected]> wrote in message news:TI4%[email protected]...
> The project I'm working on requires a butt joint that will undergo a
> little
> stress. I'm obviously going the glue the length of the joint, but I'd like
> to reinforce it with a)screws, b)dowels, or c)biscuits. Anyone have an
> opinion as to which of these 3 would add the most strength to the joint?

Does it have to be butt or can it be a lap joint? Or can you cut the pieces
staggered (like mirrored L's) so at least some portion of the joint it grain
to grain?

Jj

"John"

in reply to [email protected] on 05/05/2007 7:15 PM

06/05/2007 2:36 PM


<[email protected]> wrote in message news:TI4%[email protected]...
> The project I'm working on requires a butt joint that will undergo a
> little
> stress. I'm obviously going the glue the length of the joint, but I'd like
> to reinforce it with a)screws, b)dowels, or c)biscuits. Anyone have an
> opinion as to which of these 3 would add the most strength to the joint?

Weld it, make sure to use stainless welding rod so it won't rust.

b

in reply to [email protected] on 05/05/2007 7:15 PM

08/05/2007 6:04 PM

We're talking shear stress, as the joint involves the foot underneath a
murphy bed. The foot folds out from the top of the bed on a pivoting board.
The joint in question is between the foot and the pivot board. The foot
meets in the middle of the board, which eliminates a scarf or half lap
joint. I'm leaning towards dowels as a strenghthener. I don't expect a whole
lot of stress on the board, but I'd rather be safe than sorry.

-Bill

PB

Pat Barber

in reply to [email protected] on 05/05/2007 7:15 PM

07/05/2007 3:00 PM

"A little stress" can be defined a number of ways..

Are we talking "shear stress" on a joint
or "sag stress" from a bookcase ?

There are big differences between a chair and a table.
Both get stress but you can guess which one receives the
very most.

What are you building will be required to give a real
answer.

[email protected] wrote:

> The project I'm working on requires a butt joint that will undergo a little
> stress. I'm obviously going the glue the length of the joint, but I'd like
> to reinforce it with a)screws, b)dowels, or c)biscuits. Anyone have an
> opinion as to which of these 3 would add the most strength to the joint?

b

in reply to [email protected] on 05/05/2007 7:15 PM

06/05/2007 4:46 PM

Thanks for the responses. I'm leaning towards dowels. To explain the project
further, it's a fold over leg for a Murphy bed. As such, the leg itself (and
the joint) is situated in the middle of the second piece which negates the
possibility of using a scarf or half-lap joint. A stopped dado is a
possibility, as long as I increase that dimension of the foot to compensate
for the depth of the dado.

-Bill

LH

Lew Hodgett

in reply to [email protected] on 05/05/2007 7:15 PM

05/05/2007 8:29 PM

RE: Subject

Couple of layers of double bias glass and some epoxy.

Lew

dd

"dadiOH"

in reply to [email protected] on 05/05/2007 7:15 PM

05/05/2007 11:07 PM

Leon wrote:
> <[email protected]> wrote in message
> news:TI4%[email protected]...
>> The project I'm working on requires a butt joint that will undergo
>> a little
>> stress. I'm obviously going the glue the length of the joint, but
>> I'd like to reinforce it with a)screws, b)dowels, or c)biscuits.
>> Anyone have an opinion as to which of these 3 would add the most
>> strength to the joint?
>
> Of the 3 choices, B.
>
> If you go to a little more trouble you could do lap joints and
> strengthen the joint considerably.

Or a scarf.

--

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


Pn

Phisherman

in reply to [email protected] on 05/05/2007 7:15 PM

06/05/2007 10:53 AM

On Sat, 5 May 2007 19:15:04 GMT, [email protected] wrote:

>The project I'm working on requires a butt joint that will undergo a little
>stress. I'm obviously going the glue the length of the joint, but I'd like
>to reinforce it with a)screws, b)dowels, or c)biscuits. Anyone have an
>opinion as to which of these 3 would add the most strength to the joint?


Butt joints are the weakest. Consider a scarf, finger or lap joint.

Lr

"Leon"

in reply to [email protected] on 05/05/2007 7:15 PM

05/05/2007 9:26 PM


<[email protected]> wrote in message news:TI4%[email protected]...
> The project I'm working on requires a butt joint that will undergo a
> little
> stress. I'm obviously going the glue the length of the joint, but I'd like
> to reinforce it with a)screws, b)dowels, or c)biscuits. Anyone have an
> opinion as to which of these 3 would add the most strength to the joint?

Of the 3 choices, B.

If you go to a little more trouble you could do lap joints and strengthen
the joint considerably.

Mt

"Max"

in reply to [email protected] on 05/05/2007 7:15 PM

05/05/2007 3:26 PM


<[email protected]> wrote in message news:TI4%[email protected]...
> The project I'm working on requires a butt joint that will undergo a
> little
> stress. I'm obviously going the glue the length of the joint, but I'd like
> to reinforce it with a)screws, b)dowels, or c)biscuits. Anyone have an
> opinion as to which of these 3 would add the most strength to the joint?

I might have the wrong mental picture but how about tongue and groove?

Max


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