cC

18/04/2004 4:07 PM

Join two pieces of plywood end-to-end? Best joint?

Hi,

I'm a real newbie but I think I can do this. I'm making a desktop out
of oak plywood (probably 3/4"). I don't think I can get a ten foot
piece of plywood so I will maybe have to join two pieces (I haven't
been to the lumber store yet). If I do need to, what's the best joint
to use. I've been reading about biscuits (not too good I think) and
splines and draw bolts. What's a good method to keep the joint solid
and resistant to separating bearing in mind that dovetails might be
out of my league a bit :)

Thanks,

Chris


This topic has 15 replies

GO

"Greg O"

in reply to [email protected] (Chris) on 18/04/2004 4:07 PM

18/04/2004 10:11 PM


"Jim K" <jkajpust@###ameritech.net> wrote in message
news:[email protected]...
> I agree that a scarf joint would be best, but another option would be
> to cut to grooves into the ends that meet and connect them with a
> spline.
>
> bad ascii art to follow:
> scarf (the angle would be much sharper (more acute))
> ____________ ___________
> | / / |
> | / / |
> | / / |
> |________ / / _____________|
>
>
> On 18 Apr 2004 16:07:12 -0700, [email protected] (Chris) wrote:
>
>

But would that be 36 or 54 degrees??
and which angle do I set on my Craftsman scarf joint cutter??
Greg

JJ

in reply to [email protected] (Chris) on 18/04/2004 4:07 PM

19/04/2004 11:41 AM

Sun, Apr 18, 2004, 4:07pm (EDT-3) [email protected] (Chris) claims:
I'm a real newbie <snip> desktop out of oak plywood (probably 3/4").
<snip> ten foot piece of plywood <snip>

OK. I've read this several time, and the responses, and am still
puzzled.

Do you want to make a desk, ten foot wide? Which would be one Hell
of a large desk. Or, do you want to make a table, ten foot wide?

JOAT
The Good are Innocent so they invented Justice. The Evil are Guilty so
they invented Mercy.
- Unknown

iI

[email protected] (Ian Dodd)

in reply to [email protected] (Chris) on 18/04/2004 4:07 PM

19/04/2004 8:06 AM

Others have suggested scarf joints, splines and other solutions.
Here's another thought, it's what I did when faced with a problem
similar to yours. I needed to join two pieces of 3/4" ply to make a
12' long board. I made what was essentially a giant rabet by removing
half the depth (3/8") by a 6" section of the end of each piece to
create a 6" lap joint. With a limited selection of tools I did this
by using a borrowed router with a 3/4" staight bit and making about 8
passes side by side (3/4" X 8 = 6"). That was for a bookshelf project
and worked great.

For an accompanying desk, I had to do several end to end joints at
various angles, not to make one long board, but to do a built-in into
a 5 sided U-shaped space. For these I used biscuit joints. Each
section was also supported by the underlying framework. This desk now
carries two 19" CRT monitors, printer, fax machine, answering machine
and an ever-deepening pile of papers with no problem.

My $0.02 worth,

Ian

[email protected] (Chris) wrote in message news:<[email protected]>...
> Hi,
>
> I'm a real newbie but I think I can do this. I'm making a desktop out
> of oak plywood (probably 3/4"). I don't think I can get a ten foot
> piece of plywood so I will maybe have to join two pieces (I haven't
> been to the lumber store yet). If I do need to, what's the best joint
> to use. I've been reading about biscuits (not too good I think) and
> splines and draw bolts. What's a good method to keep the joint solid
> and resistant to separating bearing in mind that dovetails might be
> out of my league a bit :)
>
> Thanks,
>
> Chris

jj

jo4hn

in reply to [email protected] (Chris) on 18/04/2004 4:07 PM

19/04/2004 3:16 PM

[snip]
> But would that be 36 or 54 degrees??
> and which angle do I set on my Craftsman scarf joint cutter??
> Greg
>
Got me giggling on that one. LOL.
mahalo,
jo4hn

Dd

"Dan"

in reply to [email protected] (Chris) on 18/04/2004 4:07 PM

18/04/2004 11:15 PM

Your can get 10' long plywood and for that matter veneer if you want. Just
sho around. In my opinion, it would be better than having a seem.

Dan
"Chris" <[email protected]> wrote in message
news:[email protected]...
> Hi,
>
> I'm a real newbie but I think I can do this. I'm making a desktop out
> of oak plywood (probably 3/4"). I don't think I can get a ten foot
> piece of plywood so I will maybe have to join two pieces (I haven't
> been to the lumber store yet). If I do need to, what's the best joint
> to use. I've been reading about biscuits (not too good I think) and
> splines and draw bolts. What's a good method to keep the joint solid
> and resistant to separating bearing in mind that dovetails might be
> out of my league a bit :)
>
> Thanks,
>
> Chris

jj

jo4hn

in reply to [email protected] (Chris) on 18/04/2004 4:07 PM

19/04/2004 3:21 PM

Chris wrote:

> Hi,
>
> I'm a real newbie but I think I can do this. I'm making a desktop out
> of oak plywood (probably 3/4"). I don't think I can get a ten foot
> piece of plywood so I will maybe have to join two pieces (I haven't
> been to the lumber store yet). If I do need to, what's the best joint
> to use.

You might think about tongue and groove or a glue joint (need router or
shaper). A cleat glued and screwed to the underside will improve
strength.
mahalo,
jo4hn
p.s. A ten foot desk? You must be awfully busy. :-)

Rr

"Rob"

in reply to [email protected] (Chris) on 18/04/2004 4:07 PM

18/04/2004 7:01 PM

I have seen router bits that are designed to edge join plywood together.

Look around and I'm sure you can find a set.

Rob


"Chris" <[email protected]> wrote in message
news:[email protected]...
> Hi,
>
> I'm a real newbie but I think I can do this. I'm making a desktop out
> of oak plywood (probably 3/4"). I don't think I can get a ten foot
> piece of plywood so I will maybe have to join two pieces (I haven't
> been to the lumber store yet). If I do need to, what's the best joint
> to use. I've been reading about biscuits (not too good I think) and
> splines and draw bolts. What's a good method to keep the joint solid
> and resistant to separating bearing in mind that dovetails might be
> out of my league a bit :)
>
> Thanks,
>
> Chris

DB

Danny Boy

in reply to [email protected] (Chris) on 18/04/2004 4:07 PM

18/04/2004 8:20 PM

On 18 Apr 2004 16:07:12 -0700, [email protected] (Chris) wrote:


>I'm a real newbie but I think I can do this. I'm making a desktop out
>of oak plywood (probably 3/4"). I don't think I can get a ten foot
>piece of plywood so I will maybe have to join two pieces (I haven't
>been to the lumber store yet). If I do need to, what's the best joint
>to use. I've been reading about biscuits (not too good I think) and
>splines and draw bolts. What's a good method to keep the joint solid
>and resistant to separating bearing in mind that dovetails might be
>out of my league a bit :)

Over that length you *will* be supporting and attaching it on a good
strong frame. If you can get he 10' length home intact, do so. If
not, join two with either a long spline (my preference, but there are
pros here much more knowledgeable) or biscuits. Once joined and glued
it should hold when screwed to the frame well enough.

3/4"? The old school desk I'm sitting at right now is 1.5", and it's
only 5' long. As I said, oak, but more 'solid', not ply veneer.

Dan.

JC

"J. Clarke"

in reply to [email protected] (Chris) on 18/04/2004 4:07 PM

19/04/2004 2:41 PM

Chris wrote:

> Hi,
>
> I'm a real newbie but I think I can do this. I'm making a desktop out
> of oak plywood (probably 3/4"). I don't think I can get a ten foot
> piece of plywood so I will maybe have to join two pieces (I haven't
> been to the lumber store yet). If I do need to, what's the best joint
> to use. I've been reading about biscuits (not too good I think) and
> splines and draw bolts. What's a good method to keep the joint solid
> and resistant to separating bearing in mind that dovetails might be
> out of my league a bit :)

Marine plywood used to come 12' long although I can't find an online source
without more looking than I want to do right now (try M.L. Condon, they
don't have an ecommerce site but if it's used for boatbuilding odds are
they have it).

<http://www.glen-l.com/wood-plywood/scarf-butt.html> describes a couple of
accepted methods of making structural joints for boatbuilding.

<http://www.aircraftspruce.com/catalog/topages/planer.php> lists attachments
for several brands of planer (hand-held planer, not fixed mount) for
cutting scarfs acceptable for aircraft use.

> Thanks,
>
> Chris

--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)

cC

in reply to [email protected] (Chris) on 18/04/2004 4:07 PM

19/04/2004 6:21 PM

[email protected] (J T) wrote in message news:<[email protected]>...
> Sun, Apr 18, 2004, 4:07pm (EDT-3) [email protected] (Chris) claims:
> I'm a real newbie <snip> desktop out of oak plywood (probably 3/4").
> <snip> ten foot piece of plywood <snip>
>
> OK. I've read this several time, and the responses, and am still
> puzzled.
>
> Do you want to make a desk, ten foot wide? Which would be one Hell
> of a large desk. Or, do you want to make a table, ten foot wide?
>
> JOAT
> The Good are Innocent so they invented Justice. The Evil are Guilty so
> they invented Mercy.
> - Unknown
I'm making it 10' long and a little over 2' wide. Thanks for the
responses by the way...

cC

in reply to [email protected] (Chris) on 18/04/2004 4:07 PM

20/04/2004 10:51 AM

"J. Clarke" <[email protected]> wrote in message news:<[email protected]>...
> Chris wrote:
>
> > Hi,
> >
> > I'm a real newbie but I think I can do this. I'm making a desktop out
> > of oak plywood (probably 3/4"). I don't think I can get a ten foot
> > piece of plywood so I will maybe have to join two pieces (I haven't
> > been to the lumber store yet). If I do need to, what's the best joint
> > to use. I've been reading about biscuits (not too good I think) and
> > splines and draw bolts. What's a good method to keep the joint solid
> > and resistant to separating bearing in mind that dovetails might be
> > out of my league a bit :)
>
> Marine plywood used to come 12' long although I can't find an online source
> without more looking than I want to do right now (try M.L. Condon, they
> don't have an ecommerce site but if it's used for boatbuilding odds are
> they have it).
>
> <http://www.glen-l.com/wood-plywood/scarf-butt.html> describes a couple of
> accepted methods of making structural joints for boatbuilding.
>
> <http://www.aircraftspruce.com/catalog/topages/planer.php> lists attachments
> for several brands of planer (hand-held planer, not fixed mount) for
> cutting scarfs acceptable for aircraft use.
>
> > Thanks,
> >
> > Chris

Actually, it looks like a 4'x10' piece is a regular stock item. I
think the opening is about 1/8" bigger than 10' so I may need some
sort of shim to fill up the space. I wonder if there is a decorative
way to fill the space on all three sides with some sort of a molding.

fF

[email protected] (Fred the Red Shirt)

in reply to [email protected] (Chris) on 18/04/2004 4:07 PM

19/04/2004 4:46 PM

"Dan" <[email protected]> wrote in message news:<[email protected]>...
> Your can get 10' long plywood and for that matter veneer if you want. Just
> sho around. In my opinion, it would be better than having a seem.
>

4 x 10 and 4 x 12 are standard sizes for matine plywoods.

--

FF

JK

Jim K

in reply to [email protected] (Chris) on 18/04/2004 4:07 PM

19/04/2004 12:17 AM

I agree that a scarf joint would be best, but another option would be
to cut to grooves into the ends that meet and connect them with a
spline.

bad ascii art to follow:
scarf (the angle would be much sharper (more acute))
____________ ___________
| / / |
| / / |
| / / |
|________ / / _____________|


On 18 Apr 2004 16:07:12 -0700, [email protected] (Chris) wrote:

>Hi,
>
>I'm a real newbie but I think I can do this. I'm making a desktop out
>of oak plywood (probably 3/4"). I don't think I can get a ten foot
>piece of plywood so I will maybe have to join two pieces (I haven't
>been to the lumber store yet). If I do need to, what's the best joint
>to use. I've been reading about biscuits (not too good I think) and
>splines and draw bolts. What's a good method to keep the joint solid
>and resistant to separating bearing in mind that dovetails might be
>out of my league a bit :)
>
>Thanks,
>
>Chris

DW

"Dave W"

in reply to [email protected] (Chris) on 18/04/2004 4:07 PM

18/04/2004 7:53 PM

This is done all the time in boatbuilding. Scarf joints are the most often
used. I would recommend thinking hard before ordering a long sheet. A
friend ordered a 16 foot sheet of plywood, at great expense, it had to be
picked-up at the distributor. He found that it could not be carried on his
station wagon. He went to the nearest hardware store, bought a handsaw, got
the two pieces home and learned how to make a nice scarf joint.
Dave


"Chris" <[email protected]> wrote in message
news:[email protected]...
> Hi,
>
> I'm a real newbie but I think I can do this. I'm making a desktop out
> of oak plywood (probably 3/4"). I don't think I can get a ten foot
> piece of plywood so I will maybe have to join two pieces (I haven't
> been to the lumber store yet). If I do need to, what's the best joint
> to use. I've been reading about biscuits (not too good I think) and
> splines and draw bolts. What's a good method to keep the joint solid
> and resistant to separating bearing in mind that dovetails might be
> out of my league a bit :)
>
> Thanks,
>
> Chris

Kk

"KB8QLR"

in reply to [email protected] (Chris) on 18/04/2004 4:07 PM

19/04/2004 1:36 PM

Hi Chris,
How about a tongue-and-groove? You would have to do the cutting with a
router. I had to chuckle when thinking about doing it on the TS.
Have fun !
Joe


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