# Plywood joinery



## bradgranath (Jun 9, 2020)

I have an idea for a king bed made from a frame of 15in plywood cubes, sandwiching 3 plywood "floortimber" type crossmembers, with two rows of these cubes on either side, and a row of cubes at the foot of the bed.

I'm trying to think about the joinery to be used on the 15in plywood boxes. I imagined finger joints, but research indicates this is a bad idea. I would like to optimize for ease of technique for a carpenter with limited tools, and allowing for extra tolerance, while maximizing structural integrity.

Alternatively, I could send this out to be laser cut.

What joints should I use to make the boxes?

Alternatively, this easily be less expensive for me to outsource this to an appropriate shop.

Thanks!


----------



## sunnybob (Sep 3, 2016)

Am I right, there will a solid mass of cubes? If so, why? none of the interior ones will ever be seen and you will spend 10 times what a single frame would cost.


----------



## John Smith_inFL (Jul 4, 2018)

welcome to the forum, Brad.
what part of the country are you in ?
a simple sketch or drawing would put us all on the same page
as you in your thought process.
this would get you the most accurate responses for your concerns.

like Bob said: they will not be seen I would just glue and nail them 
together. I've seen waterbeds with very similar (interlocking) support frames.
(you might want to google that)

.


----------



## woodnthings (Jan 24, 2009)

*Why use cubes?*

Cubes are 6 sided and will not show when covered. Why not make a frame that will give great support and even be a "take down" for moving about? Make a grid of 3/4" plywood using "cross joints" that "lock" together when assembled. This is video shows a smaller scale than you would use for a bed frame which would be high enough for sitting.









Your frame can be covered with a sheet(s) of 3/4" plywood to make a smooth support for any type of mattress ..... water, air, foam etc.
:vs_cool:


----------



## Tool Agnostic (Aug 13, 2017)

For us, the undersides of beds provide a large volume of valuable storage. They offer easy access, too. We use the space for seasonal items, like summer/winter bedding and holiday decorations. Our children used them for closet overflow when they were younger. 

We use shallow boxes and trays with rollers/wheels to make access easy.

That space is too valuable to block off (pun intended).


----------



## bradgranath (Jun 9, 2020)

Thanks for all the interest! I'm in Southern California. A king mattress is nearly square: 15 inches times 5 boxes per side, make a roughly 80x80 frame (lotsa fudgefactor in here still, but we're not at that step yet) I'm still just trying to get the general concept in mind.

It is correct that If you build the whole platform from boxes, that the inner ones are pretty useless. Also, the headboard will be against the wall, so those boxes won't be seen/used either. My idea was to build boxes around the outside, with crossmembers to hold up the middle, like:










(Yellow=side boxes, red=end boxes, blue=crossbrace)

These would be 5 sided boxes (one open face) and the size would be about right for each box to hold one of these or like a milk crate.










The boxes would be bolted together, not glued, so that when the frame is disassembled the boxes double as crates.


----------



## woodnthings (Jan 24, 2009)

*Crates? ... OK, then .....*

Why not use milk crates? Not actual ones, but the type found at Target, Home Depot etc, for misc. storage. College students use them for many things, but maybe never a bed support.... who knows? Cheap, already made, available and open on the top for storage. 



:smile2:


----------



## bradgranath (Jun 9, 2020)

I would not be able to control the final dimensions, and I think I'm looking for something a little sturdier.


----------



## JohnGi (May 9, 2019)

I can see what you are trying to do, but from a manufacturing perspective it just does not work. Board products, and especially veneer construction plywood, are not suited for corner fabrication--particularly with constraints on equipment. I've seen stuff like this made out of mdf or similar composite boards in plants that really know how to use double end tenoners, but it ends up being high end furniture by the time all is said and done. You could probably engineer a structure like you have drawn to work with heavy cardboard boxes, which were not something I ever had to design, rather than any type of wood material a carpenter would be familiar with.


----------



## woodnthings (Jan 24, 2009)

*Sturdier?*



bradgranath said:


> I would not be able to control the final dimensions, and I think I'm looking for something a little sturdier.



https://www.google.com/search?client=firefox-b-1-d&q=plastic+milk+crate

https://www.milkcratesdirect.com/su...zYTSEmRch0tWWJc9Jbmx6wBFJ0BIl8YRoCnQUQAvD_BwE
The plastic milk crates are very strong in compression. I can put a piece of 1/2" plywood on it and stand on it with 200 lbs. In fact, I did this to get into my lifted 4 X 4 truck because it was strong and light and would fit inside the cab. The above link shows they come in various sizes.


----------



## bradgranath (Jun 9, 2020)

Hmmm, maybe they would hold up. How would I fasten them together?


----------



## kiwi_outdoors (Jan 15, 2020)

My home-made waterbed base and frame used "2x4" and "2x3" frames (some with ply infills); ply bed base, and "2x8" sides topped with "2x3" (its actually all metric lumber, I did this in Scotland decades ago). Its been moved a few times and put in storage once. It includes 3 large under-bed drawers each side - which have been invaluable fro storing things like camping clothes, ski clothes, scuba stuff. 

Its always about storage.


----------



## sunnybob (Sep 3, 2016)

How often are you planning to move?
With the amount of material you need to buy to make that bed you could save enough on a conventional design to pay for any amount of cardboard boxes when you did want to move. Let alone the hours and hours (make that days) required to make it.
Also, 15" high base is a very low bed base unless you are young and agile.

Not all "good ideas" translate into real life, I'm afraid this is one one of those.


----------



## Tony B (Jul 30, 2008)

*Back to Original Question*

Simple butt joints, either nailed or screwed would be more than strong enough for what you are doing.
The problem would be an aesthetic one - the edges of the plywood exposed. If this is what you want to do, then automobile or woodworkers Bondo will smooth out the rough edges to where they can be painted. If you have the ability to miter the corners, that would solve the 'edge' problem. The miter joints will not be as strong butt joints, but they should still be able to get what you want. A vertical load using boxes should hold up the Empire State Building. (Figure of speech - don't want to get the engineers riled up)
If you are going to put liner boxes inside for storage purposes, I would make the inside of the boxes approx 1/2 larger than the liners. that way they wont jam when you tip the boxes upside down to get the liner out.
Have you thought about not even using a box inside the boxes? Plywood makes a good liner for clothing items. 

Here is another idea about the boxes to resolve the 'edge' problem. You get or make 3/4" square sticks. Nail the sticks to the plywood edges and that will hide it. If you wanted to get creative, you could use 1" square sticks and the vertical edges can be left proud of the surface. If you are going to paint the boxes, maybe paint the vertical sticks a contrasting color. 

Just remember to post photos of progress and the finished product

Good luck and have fun in whatever you choose.


----------



## woodnthings (Jan 24, 2009)

*I would use zip ties.*



bradgranath said:


> Hmmm, maybe they would hold up. How would I fasten them together?



Zip ties are very strong, cheap, and easily removed if the need arises by cutting them ...... scissors, knife, or side cutters. If they can hold records, they will hold just about anything. If you don't like the open look, use a plywood panel as a surround. You can leave open "gaps" between them for storage of longer stuff, golf clubs, picks and shovels, 

tennis rackets, etc. and they will still easily support all the weight if you use a plywood top cover. 





Is this for a water bed?


----------



## JayArr (Sep 18, 2018)

For a load bearing base a cheaper, easier, faster design would be to build Xs that slot into each other. It'll take half the material, it requires no mitre cuts, it assembles and dis-assembles without tools and if you slice the top plywood that goes over it all into two or three sections it should all fit in a Volkswagon Rabbit (I fit a homemade water bed into mine in College with all the doors and hatch closed). Each X in the picture replaces a box but takes two pieces of plywood instead of 5. If you need storage the baskets will still fit between the Xs under the bed. If you have a router you could take the plywood that goes over the Xs and route channels into it that the top of the Xs would sit in, that would ensure they don't move during sex.


----------



## Tony B (Jul 30, 2008)

bradgranath said:


> Hmmm, maybe they would hold up. How would I fasten them together?


The easiest, fastest way is to drill a hole between adjacent boxes and for fast disassembly, use screws, washers and wingnuts.

If on a haed surface, use non-skid on the bottoms. If on a carpet, they might not move at all. If you didn't need every box for storage, you could invert every other box. The hollow bottom would definitely not move on carper. 

If you covered the top of all the boxes with a single sheet of 1/2" plywood. there would be no impressions from the boxes on the mattress or box spring.

Also note, that if you had one box in the middle, the plywood sheet would spread the weight across the entire surface and you would not need those boards.

As for the plywood sheet, it would really have to be 2 sheets cut equal widths and spliced together in the middle with 2 smaller sections. Use the waste plywood and make 2 strips in the middle to apply across the seams for and aft with the center box in the middle. by removing some of the boxes you can work from the underside. Or, work from the top by sliding the 2 main boards over to one side to make the connection, then slide back into position.


----------



## GCTony (Apr 5, 2018)

If painted, how about MDF? I even clear coated MDF and it looked pretty good. (not my style) Attaching them together, could use sex bolts. 

TonyB may be able to explain this better: I understand this is a totally different direction but...the queen bed in the RV I used to have was a plywood sheet that the mattress sat on. Under that plywood sheet was a big box about 5' X 7' about 16" high. The bed was basically on a hing and gas "springs" where you lifted the whole thing up to access the storage.


----------



## Nick2727 (Jun 14, 2020)

This bed is bit different, one that i plan on building eventually. 



Pocket holes is all it says.


https://www.ana-white.com/woodworking-projects/classic-storage-bed-king


----------



## bradgranath (Jun 9, 2020)

That's exactly what I'm trying to build, just sliiiightly more modular and with a much rougher finish (no fancy trim bits). Why is everyone trying to head me off at the pass?


----------



## Tony B (Jul 30, 2008)

bradgranath said:


> ...................... Why is everyone trying to head me off at the pass?


Because that is what we do. LOL Just a bunch of old guys killing time and having fun. 
FWIW, Some people on here actually go a whole different direction after reading all the replies. Not often, but sometimes. Others just slash their wrists. 

I like your design and I know you will have fun building it. 

Post lots of pics.


----------



## Nick2727 (Jun 14, 2020)

Not sure Im grasping the heading off at the pass comment. Lol


----------



## woodnthings (Jan 24, 2009)

*Stopping him before he ......*



Nick2727 said:


> Not sure Im grasping the heading off at the pass comment. Lol



Some of the suggestions are alternate paths to achieve the same result with, less cost and much less work. It is up to the OP to take the advice or to stay on the path he has chosen. We have attempted to "head him off at the pass" before he gets too far down the bumpy trail and may get ambushed. Yep, old guys havin' fun also ....... >


----------



## Nick2727 (Jun 14, 2020)

That makes sense. Lol


----------



## bradgranath (Jun 9, 2020)

Aaaaaaaall righty then! I found these "S-Crates" from https://www.milkcratesdirect.com/super-crates/s-crate-1 
Trouble is, they cost more to ship than they do to buy. But weirdly, "Walmart.com" offered _free_ FedEx shipping. Of _20 completely un nestable crates_. They were clearly just drop shipped from the above website, since they came by air from DE! (I'm in SoCal). Very weird, but I'm not complaining. Picked up a couple 8ft sheets of 1/2in MDF and some pine boards. Sleeping on the mock-up tonight, took 20 minutes to assemble, feels very solid. That was a TON of work saved [woodnthings]. Thanks! Will post pix when I put it together tomorrow!


----------



## Echo415 (Apr 3, 2018)

woodnthings said:


> Some of the suggestions are alternate paths to achieve the same result with, less cost and much less work. It is up to the OP to take the advice or to stay on the path he has chosen. We have attempted to "head him off at the pass" before he gets too far down the bumpy trail and may get ambushed. Yep, old guys havin' fun also ....... >


I'd go with a higher cost and less work option myself. I've been looking for an excuse to get the dado set below...a project like this would give me the excuse to spend money without getting yelled at too much.

https://www.rockler.com/rockler-mit...Wr4exJ8bSyD9Sz2jAgqbsIzaAvPfp-fBoCAtkQAvD_BwE


----------



## Tool Agnostic (Aug 13, 2017)

Echo415 said:


> I'd go with a higher cost and less work option myself. I've been looking for an excuse to get the dado set below...a project like this would give me the excuse to spend money without getting yelled at too much.
> 
> https://www.rockler.com/rockler-miter-fold-dado-set-plus


I looked at that same miter fold and dado set and saw the demo at my local Rockler store. They had a few of the previous non-coated version in the closeout area for a fantastic price. The ones they had on closeout (now gone) were the same blades, but without the blue anti-friction coating. I almost bought one, until I learned that:

*Caveat: The Rockler miter fold dado set is NOT compatible with SawStop table saws. *


----------



## Mystri (Jul 1, 2020)

Tool Agnostic said:


> I looked at that same miter fold and dado set and saw the demo at my local Rockler store. They had a few of the previous non-coated version in the closeout area for a fantastic price. The ones they had on closeout (now gone) were the same blades, but without the blue anti-friction coating. I almost bought one, until I learned that:
> 
> *Caveat: The Rockler miter fold dado set is NOT compatible with SawStop table saws. *



As I understand only the SawStop dado set is compatible because of the brake cartridge??


I am considering buying different tablesaw due to this limitation. I want very much to use a molding head with interchangeable knives and I suspect it wouldn't work


----------



## Tool Agnostic (Aug 13, 2017)

Mystri said:


> As I understand only the SawStop dado set is compatible because of the brake cartridge??
> 
> I am considering buying different tablesaw due to this limitation. I want very much to use a molding head with interchangeable knives and I suspect it wouldn't work


SawStop makes two different brakes: 
* Standard 10 inch blades use the standard brake. 
* 8 inch dado sets use the dado brake. SawStop works with nearly all 8 inch dado sets that have winged chippers. I use the "budget" Freud SD208 set, but would prefer a DeWalt DW7670 or Forrest Dado King dado set.

There are a few restrictions for SawStop table saws:

SawStop does not recommend blades with depth-limiting shoulders behind the carbide tips. I call them "anti-kickback tails." Freud makes several blades with depth-limiting shoulders. Here is an example. Look at a closeup of the carbide tips to see the depth-limiting shoulders:
_NOT RECOMMENDED_: https://freudtools.com/products/SBOX8

Dado sets must be 8 inch and use chippers with two or four "wings." You should _not_ use dado sets with "full body" chippers. My SD208S dado set has two-wing chippers. This Oshlun dado set is _not acceptable_, because it has full body chippers:
_NOT ACCEPTABLE_: http://www.oshlun.com/stack_dado_set_professional.html

Here are some additional blades that are _not acceptable_ for SawStop table saws:
* 6 inch dado sets.
* Wobble-type dado blades.
* The Rockler miter fold dado set. In addition to avoiding the miter fold blade, Rockler instructions say not to use the dado components, but they do not say why. 
* Molding heads.
* (Rare) Non-conductive blades, or blades with non-conductive coatings throughout.
* etc.

Here is a nice article about dado sets and SawStop:
https://www.trentdavis.net/2016/08/31/dado-information/


----------



## Mystri (Jul 1, 2020)

@Tool Agnostic


Very informative!


Note; the rocker miter fold set doesn't work because it's larger than 8" - I read that you can't even get it to work with bypassing cause sawstop basically can't "see" it at all.


Kinda the same sizing problem with the molding knife head I want - http://corobcutters.com/accessories.aspx -- it's only 7" so my understanding is it wouldn't work :crying2:


----------



## Tool Agnostic (Aug 13, 2017)

Mystri said:


> @Tool Agnostic
> 
> Very informative!
> 
> ...


Molding heads are not compatible with SawStop saws. 

I tend to focus a lot on safety. I like the "insurance" that the SawStop safety mechanism provides. I am willing to live with its limitations (no molding heads, no 6 inch dado sets, etc.). To be honest, the limitations have never held me back, and I recommend SawStop saws to others. Despite the safety feature, I still use the SawStop saw the same as any other table saw - with the best safety practices I know. Other than demos, I have never triggered a SawStop brake, and hope I never do. 

I have never used molding heads, but be aware that they can be very dangerous; one of the most dangerous things you can do with a table saw. I know more than one woodworker who has told me that the scariest tool in their shop is the molding head. Many refuse to use them. As a "newbe", be sure you do all of your safety homework before you move on to molding heads.


----------



## MattWll (Jul 7, 2020)

And I like how it looks. Good luck building!


----------



## Mystri (Jul 1, 2020)

Tool Agnostic said:


> Molding heads are not compatible with SawStop saws.
> 
> I tend to focus a lot on safety. I like the "insurance" that the SawStop safety mechanism provides. I am willing to live with its limitations (no molding heads, no 6 inch dado sets, etc.). To be honest, the limitations have never held me back, and I recommend SawStop saws to others. Despite the safety feature, I still use the SawStop saw the same as any other table saw - with the best safety practices I know. Other than demos, I have never triggered a SawStop brake, and hope I never do.
> 
> I have never used molding heads, but be aware that they can be very dangerous; one of the most dangerous things you can do with a table saw. I know more than one woodworker who has told me that the scariest tool in their shop is the molding head. Many refuse to use them. As a "newbe", be sure you do all of your safety homework before you move on to molding heads.



Yeah I'll be keeping track of all my fingers and thumbs for sure.


----------



## woodnthings (Jan 24, 2009)

*There are two types of molding sets .....*



Mystri said:


> Yeah I'll be keeping track of all my fingers and thumbs for sure.



This Ebay search listing shows a 3 wing cutter head and just below a single wing cutter head:
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=Craftsman+molding+set&_sacat=0






















I have the 3 cutter version, only used it a few times, BUT here's what I learned. Use a dado insert in your table saw throat opening.
Make several passes leaving only a light one for last. Use feather boards to hold the work to the fence and if possible down to the table as well. Do not use your hand or fingers to push the workpiece, rather a pusher the same size as the workpiece so it fits within the holddowns.
One of my favorite You Tubes showing making moldings using a radial arm saw and various cutter heads:


----------

