Hello,

I'm designing a bed and am looking for some advice on how to deal with
suspending a king size futon mattress with out resorting to using a fifth
center leg.

The basic support structure is a box the same width and length as an
"eastern" king and ~8" high. I plan on using 3 internal, lengthwise
beams in addition to the 2 side rails of the box to support many slats
running crosswise. The box will be constructed using cross halving
joints. It will be topped with a large "picture frame" and will rest on
4 legs which, finally, rest on casters. The lengthwise beams will attach
to the head/foot boards with through and wedged M&T and the slats will
attached by sliding into mortises dadoed into the side rails before the
"picture frame" is laid down. The slats will be at least pinned to keep
them from working loose but I'm also thinking to wedge them to provide
some tensioning.

So, some questions:

What wood and dimensions can people suggest for the beams and slats? Any
rule on how large of a gap between the slats can be tolerated before being
felt though the futon? Should I use more than 3 beams? Could less be
used and still provide the support?

Is the tensioning of the slats a good idea? Will the wood stretch over
time (I would guess so) and if so, can this be chased by periodically
pounding in the wedges or replacing them with larger ones? Are some woods
better suited for being tensioned?

Thanks for any comments!
-Brett.

On Sun, 03 Apr 2005 14:12:58 -0400, Brett Viren
wrote:

What wood and dimensions can people suggest for the beams and slats?

Ash, maybe hickory in the USA. They should be straight grained, split
coppiced timber is good (and cheap) if you can get it.

I'd make the slats about 4" across, but this isn't critical. The gaps
aren't important for anything else other than allowing the slats to
move freely, so bunch them up tight if you're worried about feeling
them. I'm not a lover of futons, I prefer latex foam. One doesn't mid
gaps, but will let you feel them. Latex itself doesn't like big gaps
and will wear badly. I use 1/2", maybe 1" max.

Should I use more than 3 beams?

I'd just use one, maybe two - although past experience of working on
beds for Americans has been that they need a ridiculous amount of
mechanical strength and still fail. For normal size mattresses on an
English bed, I don't use any internal beams and just run the slats
full-width.

Centre beam design on beds is tricky, if you aren't going to make the
beam telegraph itself through. I'd use a single beam for a bed that
was effectively a twin, a pair of beams for those couples who both
sleep in the centre.

Typical joints if you do go for a central beam are to either run the
slats one-piece and full-width, or to narrow the ends of each slat
down to about 1/2 width symmetrically and interleave them (the slats
are staggered). This also works for Orthodox Jewish double beds, where
they have to be separable (the "beam" is the doubled side frame of the
two halves).

Is the tensioning of the slats a good idea?

Not in my book. I mount them as loosely as possible, to avoid
squeaking.

I just mount my slats by loosely placing them over a locating pin.
Generally I make bed frames from welded steel and this is just 1/4"
rod, welded onto the frame.

Will the wood stretch over time

No, but it may take some permanent curvature. Softwood will do this
more readily, especially if it's fairly new timber..


--
Smert' spamionam

The lengthwise beams will attach
to the head/foot boards with through and wedged M&T and the slats will
attached by sliding into mortises dadoed into the side rails before the
"picture frame" is laid down. The slats will be at least pinned to keep
them from working loose but I'm also thinking to wedge them to provide
some tensioning.


If I follow correctly, this is all fixed joinery. This is going to be a
beast move (as in down staircase, around a corner and through a door).

Bed bolts a great because it allows the structure to be broken dorn into
pieces. It also allows you to snug up the joinery at a later date if the bed
is subjected to too much racking force :-)

If I were you, I would construct it like a normal bed (headboard, footboard
and rails that detatch from one another) and build a torsion box that sits
inside the rails.

FWW has an article a couple of months back on the anatomy of bed
construction. You may want to pick that up.

-Steve

Brett Viren wrote:
What wood and dimensions can people suggest for the beams and slats? Any
rule on how large of a gap between the slats can be tolerated before being
felt though the futon? Should I use more than 3 beams? Could less be
used and still provide the support?

Is the tensioning of the slats a good idea? Will the wood stretch over
time (I would guess so) and if so, can this be chased by periodically
pounding in the wedges or replacing them with larger ones? Are some woods
better suited for being tensioned?

I made a queen size bed for my son last fall. There is no center
support (leg or beam). I made the slats from 3/4" poplar. There were 9
slats total and it uses a foam mattress. Each slat was made using 3.5"
wide boards (1 x 4). I ripped a 1" section off the side of each board,
then turned it 90 degrees and glued it back to the rest of the board.
This gave each slat an 'L' cross section which substantially increased
the stiffness while only slightly increasing the overall thickness. It
seems to be working fine for the past four months.

On Mon, 04 Apr 2005 09:20:37 -0400, Stephen M wrote:

The lengthwise beams will attach
to the head/foot boards with through and wedged M&T and the slats will
attached by sliding into mortises dadoed into the side rails before the
"picture frame" is laid down. The slats will be at least pinned to keep
them from working loose but I'm also thinking to wedge them to provide
some tensioning.


If I follow correctly, this is all fixed joinery. This is going to be a
beast move (as in down staircase, around a corner and through a door).

Just about everything is to be held together with wedged, through tenons
and the large cross halving joints for the head/foot-to-rails joints.
The only glue will be the used to construct the legs and to lay down the
parts of the "picture frame" (there must be a better term) to the
head, foot and rail boards. This latter will be done so that everything
can still be broken down.

BTW, the inspiration comes from a Japanese bed I once saw.
Here is a diagram I think I found posted to this ng a while ago (thanks
to whomever is hosting it) that should show roughly what I mean.

http://hamiltonwoodworks.com/drichards/Misc/KoaBed.jpg

I'd like to have some nice program like that which made this drawing.
as all I have now are pages and pages of notebook entries that probably
would only make sense to me. But anyways, my variations are mostly design
and not not structural.

-Brett.

On Sun, 03 Apr 2005 20:42:11 +0100, Andy Dingley wrote:

On Sun, 03 Apr 2005 14:12:58 -0400, Brett Viren
wrote:

What wood and dimensions can people suggest for the beams and slats?

Ash, maybe hickory in the USA.

Thanks, Andy. I thought hickory might be suitable, I'll look in to ash
also. I'm still trying to track down a good source of hardwood (in
eastern L.I. NY) so having two possibilities will help.

Should I use more than 3 beams?

I'd just use one, maybe two - although past experience of working on
beds for Americans has been that they need a ridiculous amount of
mechanical strength and still fail.

Heh, maybe I should stick with 3 but just put them all on my side of the
bed!

[ ... other helpful things snipped ... ]

Thanks again,
-Brett.

BTW, the inspiration comes from a Japanese bed I once saw.
Here is a diagram I think I found posted to this ng a while ago (thanks
to whomever is hosting it) that should show roughly what I mean.

http://hamiltonwoodworks.com/drichards/Misc/KoaBed.jpg

I'd like to have some nice program like that which made this drawing.

Why can't you just describe tha joint with plain text? ;-)

On Tue, 05 Apr 2005 08:24:01 -0400, Stephen M wrote:


BTW, the inspiration comes from a Japanese bed I once saw.
Here is a diagram I think I found posted to this ng a while ago (thanks
to whomever is hosting it) that should show roughly what I mean.

http://hamiltonwoodworks.com/drichards/Misc/KoaBed.jpg

I'd like to have some nice program like that which made this drawing.

Why can't you just describe tha joint with plain text? ;-)

Well, the Koa bed joint, I guess I could but I'm going after something a
bit more complex. I still haven't understood all of it for my self. I'm
new to wood working (in case it wasn't obvious) and playing with some
solid modeler would really help here.

But, I'll try: Instead of a solid square post I want a tapered hollow
"truncated, inverted pyramid" and instead of the leg being square to the
bed it will be off by 45 deg which will match up with a 45 miter I'll take
out of the "picture frame". The two proud ends of the "x" of the cross
halve joint joining the foot/head board to the side rails will follow the
same taper of the legs and will partially protrude through the walls.
Also, the casters will be half hidden up inside the legs so only an inch
or so of wheel shows.

So, you tell me, does plain text cut it?

Cheers,
-Brett.

Why can't you just describe tha joint with plain text? ;-)

snip..

But, I'll try:

Snip...

So, you tell me, does plain text cut it?

Cheers,
-Brett.

Brett, Brett Brett.

Did you not see me winking? ;-)

All the best,

Steve

Brett Viren wrote in
news
snip

I still haven't understood all of it for my self.
I'm new to wood working (in case it wasn't obvious) and playing with
some solid modeler would really help here.

But, I'll try: Instead of a solid square post I want a tapered hollow
"truncated, inverted pyramid" and instead of the leg being square to
the bed it will be off by 45 deg which will match up with a 45 miter
I'll take out of the "picture frame". The two proud ends of the "x"
of the cross halve joint joining the foot/head board to the side rails
will follow the same taper of the legs and will partially protrude
through the walls. Also, the casters will be half hidden up inside the
legs so only an inch or so of wheel shows.

So, you tell me, does plain text cut it?


I see two contradictory statements he

[New to woodworking] + [description of a joinery task which would
challenge an old chinese master]

And you want to make two pair of the legs which are mirror images of
each other, don't you?

I'm guessing that you're an engineering student.

Make prototypes of inexpensive material. And find something else to
sleep on, while you learn how to build this very ambitious project.

Have fun with the exploration.

Patriarch

On Wed, 06 Apr 2005 10:55:32 -0500, Patriarch wrote:

I see two contradictory statements he

[New to woodworking] + [description of a joinery task which would
challenge an old chinese master]

And you want to make two pair of the legs which are mirror images of
each other, don't you?

I'm guessing that you're an engineering student.

Physicist, actually, but my student days are long gone.

Make prototypes of inexpensive material. And find something else to
sleep on, while you learn how to build this very ambitious project.

Yep, our floor is very firm. So far no complaints from the queen of the
house, so I'm taking my time!

Thanks,
-Brett.

On Wed, 06 Apr 2005 09:40:03 -0400, Stephen M wrote:

Why can't you just describe tha joint with plain text? ;-)

snip..

But, I'll try:

Snip...

So, you tell me, does plain text cut it?

Cheers,
-Brett.

Brett, Brett Brett.

Did you not see me winking? ;-)

All the best,

Ah, I see. I thought that was just a nervous tick. I didn't want to
stare! grin.

I guess I still don't have an appreciation of what I'm getting myself into
with this project. When I was in college I did a bit of machining as part
of my job and a joint like this would be relatively easy to fabricate.
Of course that was using a huge, expensive and accurate mill working on
stable materials.

In fact, the first bed I made was partially built on that mill. I called
it the tennis racket bed because it used a lacing of nylon rope to support
the mattress. Dumbest thing I could have done. Every month I'd have to
re-tighten the damn thing.

Anyways, I'll be sure to post some pics when I get further. They should
be good for a laugh or two!

Cheers,
-Brett.

In fact, the first bed I made was partially built on that mill. I called
it the tennis racket bed because it used a lacing of nylon rope to support
the mattress.

That sounds like a "feature" to me :-)

bounce, bounce bounce....

On Tue, 05 Apr 2005 08:24:01 -0400, Stephen M wrote:


BTW, the inspiration comes from a Japanese bed I once saw.
Here is a diagram I think I found posted to this ng a while ago (thanks
to whomever is hosting it) that should show roughly what I mean.

http://hamiltonwoodworks.com/drichards/Misc/KoaBed.jpg

I'd like to have some nice program like that which made this drawing.

Why can't you just describe tha joint with plain text? ;-)

Instead of doing the taxes today like I should I've been playing around
with Blender and drew up the hardest part of the design I'm shooting for.
Just getting the angles right in software was tough enough. I can't
guess what it will be like once woods hits the saw. But playing with this
design in Blender really helped to understand the how this all goes
together.

If anyone is interested in the result, see here for a couple screen shots:

http://www.flickr.com/photos/bv/8945346/
http://www.flickr.com/photos/bv/8945347/

These only show the basic leg assembly and how the head, foot and side
boards join in. The border ("picture frame") isn't shown but it will be
wide enough to just cover the 3 external sides of the leg. Its corners
will be mitered to follow the leg outline and will only be glued to the
uprights to allow it to be broken down.

The part that I think I'm going to like most about this is the mitered
and beveled board ends that just poke out of the legs. I think they
should take on a darker color when finished because of being partial end
grain (right?). If so it will be a nice contrast to the leg faces.


-Brett.

Brett Viren wrote in
news
On Tue, 05 Apr 2005 08:24:01 -0400, Stephen M wrote:


BTW, the inspiration comes from a Japanese bed I once saw.
Here is a diagram I think I found posted to this ng a while ago
(thanks to whomever is hosting it) that should show roughly what I
mean.

http://hamiltonwoodworks.com/drichards/Misc/KoaBed.jpg

I'd like to have some nice program like that which made this
drawing.

Why can't you just describe tha joint with plain text? ;-)

Instead of doing the taxes today like I should I've been playing
around with Blender and drew up the hardest part of the design I'm
shooting for. Just getting the angles right in software was tough
enough. I can't guess what it will be like once woods hits the saw.
But playing with this design in Blender really helped to understand
the how this all goes together.

If anyone is interested in the result, see here for a couple screen
shots:

http://www.flickr.com/photos/bv/8945346/
http://www.flickr.com/photos/bv/8945347/

These only show the basic leg assembly and how the head, foot and side
boards join in. The border ("picture frame") isn't shown but it will
be wide enough to just cover the 3 external sides of the leg. Its
corners will be mitered to follow the leg outline and will only be
glued to the uprights to allow it to be broken down.

The part that I think I'm going to like most about this is the mitered
and beveled board ends that just poke out of the legs. I think they
should take on a darker color when finished because of being partial
end grain (right?). If so it will be a nice contrast to the leg faces.


So does your program figure out the angles of the compound miters for
you, to take to the saw?

Test your end grain amd mitered grain stain theory on scrap. Wood
species and finish types have differing results.

In this drawing program, this bed almost looks possible, with the right
tooling and sufficient space.

Patriarch

On Sun, 10 Apr 2005 02:30:58 -0500, Patriarch wrote:

So does your program figure out the angles of the compound miters for
you, to take to the saw?

It might, but I haven't ran across how. Blender isn't really a CAD
program, it is more for 3D object modeling. It's rather fun to play
with once the basic controls are learned but as far as I can tell it
lacks the usual dimensioning and other measurements that CAD provides.

I know how to calculate the miter/bevel angles used in the leg faces.
I've found various online calculators or formulae that give this. Here
is one:

http://www.scarletta.net/WoodJoy/compound_miter.html

As drawn, the leg faces have a 15 deg tilt (90-15=75 deg for that web page).

I haven't thought about the end cuts yet. At first guess I think they
need to be different than the leg faces. Compound miter cuts are still
very confusing to me. Another reason this modeling helps. And, this is all
definitely something I'll test on scrap before cutting good wood.

-Brett.