# What's the largest torsion box that can be made?



## Duane Bledsoe (Jan 6, 2013)

I have a Kreg work bench frame that measures 44" x 64". I need to make a top for it but having such a large span I worry about sagging through the middle. I have come up with various designs using 2x4 and center legs to prevent this but this will also make it very heavy. So far I am at 17-20 2x4's in the design, plus the top, plus the metal frame itself. I will need to move this later to do other work to complete my shop so this seems too heavy in my mind. So I was considering a torsion box top to keep it flat and lighter weight. Maybe all made from plywood and pocket hole joinery?


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## schnewj (Nov 18, 2013)

I would guess unlimited. However, there might have to be a proportional increase in material and construction thickness to prevent sag at some point.


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## Stick486 (Jan 4, 2013)

Duane Bledsoe said:


> I have a Kreg work bench frame that measures 44" x 64". I need to make a top for it but having such a large span I worry about sagging through the middle. I have come up with various designs using 2x4 and center legs to prevent this but this will also make it very heavy. So far I am at 17-20 2x4's in the design, plus the top, plus the metal frame itself. I will need to move this later to do other work to complete my shop so this seems too heavy in my mind. So I was considering a torsion box top to keep it flat and lighter weight. Maybe all made from plywood and pocket hole joinery?


hollow core doors are essentially torsion boxes and they can get pretty big...


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## FreeTime (Dec 2, 2012)

If you are concerned with the potential weight - 2x4s are probably over-kill. I probably shouldn't comment on this because I used 2x4s in mine - convenience/availability and it was only a 30" x 4' table. You just need something that won't compress (i.e. height) - I suspect an internal frame using 3" tall pieces of 3/4in pine or plywood would give you just as much structural support. I can't imagine 1/4" thick x 1.25" angle iron will be bending or sagging much either


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## Duane Bledsoe (Jan 6, 2013)

Stick486 said:


> hollow core doors are essentially torsion boxes and they can get pretty big...


This is true, but they are vertical instead of horizontal, so I doubt they would have the same sag factor, but then again, they are only supported from one side by the hinges so maybe they actually have to be even stronger to resist sag. Hmm...


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## Gaffboat (Mar 11, 2012)

I believe aircraft wings are basically torsion boxes and each wing on the Antonov AN-225 Mriya (one of the world's largest aircraft) is over 130 feet long and supports three engines. I think you'll be pretty safe with anything you build. :laugh:


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## old coasty (Aug 15, 2014)

For the weight problem, a set of casters that lift off the floor when in place would work. Rockler has a set that will take 400 pounds.


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## timbertailor (Oct 4, 2009)

Stick486 said:


> hollow core doors are essentially torsion boxes and they can get pretty big...



I made my own for portable work benches that use saw horses.


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## Duane Bledsoe (Jan 6, 2013)

Well, I have a concrete garage floor that is not level and even. I have to use adjustible feet to level it out, and then when I move it any rollers I use woud be up and down from each other instead of on the same plane. So I figure I'll have to just lift it.


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## Mike (Nov 22, 2004)

Duane, unless you are planning on rebuilding engines on your bench it shouldn't have a sag problem over a 5' span.


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## Stick486 (Jan 4, 2013)

Duane Bledsoe said:


> This is true, but they are vertical instead of horizontal, so I doubt they would have the same sag factor, but then again, they are only supported from one side by the hinges so maybe they actually have to be even stronger to resist sag. Hmm...


so lay the door over...
MDF/press board door fail...
real wood w/ honey comb grids do well and serve as impromptu work tables...
despite the cardboard grids and 3/32'' thick luan skins...


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## Cherryville Chuck (Sep 28, 2010)

Duane 4" wide strips of 3/4 ply or lumber should be plenty strong. Even if you are rebuilding engines on it. Even less likely to sag if you move the legs in about 6" from each end.

If you put a pair of castors on the end of one set of legs and mount them so they just barely miss the floor when the table is in use then when you lift the other end (like a wheel barrow) the table rests on the castors so that you can move it around. That's how I'm doing it with my current router table.


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## Duane Bledsoe (Jan 6, 2013)

timbertailor said:


> I made my own for portable work benches that use saw horses.


Wow, is that a hollow core lauan door? Ok, I'm convinced!


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## DesertRatTom (Jul 3, 2012)

I used 3.5 x 3/4 clear pine for my outfeed table, which I also use for assembly with a 3/4 inch thick particle board top with a plastic surface on the top. Years of use and no sag. Very light too. Be sure you joint or plane the wood you use so it is perfectly flat If you use those Rockler clickdown casters to move the table, AND some of the adjustable feet that screw up and down, you can have casters for easy movement, and levelers for the uneven floor. I would avoid making the thing out of construction grade lumber-pretty unstable stuff. In fact, I'd probably make most of the support of ply with reinforced corners for strength. This would allow for enclosed storage and help keep the sawdust out. My two cents.


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## OPG3 (Jan 9, 2011)

Duane my Friend, Torsion BOXES - TECHNICALLY - I designed one a few years ago for PEPSI COLA that was 72 feet x 32 feet x 32" deep (thick), but it was made from steel, with full penetration welds everywhere. THAT was certainly not the maximum. Oliver's idea beats mine by a mile!
From WOOD? You are limited to the maximum size of plywood you can purchase AND get to your shop. Often this is a 4'-0" x 8'-0" sheet. I had a client many years ago who had a home with a cantilevered floor in it - he special purchased PLYWOOD 16' x 32' for this floor system! IF I hadn't seen it, I would suspect someone was crazy. He told me the biggest problem was getting it delivered to the jobsite!

I just completed the construction of a large cage for an Asian Water Monitor and the cage includes a torsion box only 36" x 24". I made that box using 2x4's laying flat and constructed it as follows:
1. Bottom Layer is 5/8" plywood, which is screwed and glued to;
2. A FEW 2x4's with careful omissions for plumbing & electrical to pass through;
3. MIDDLE layer is 1/2" plywood, glued and screwed in both directions;
4. A FEW 2x4's again with careful omissions - but running perpendicular to layer 2. - this allowed a cantilever on one end (16")
5. Top Layer is 5/8" plywood, glued & screwed.

I ALSO added some full length threaded rods parallel to layers 2 & 4. The shortest length threaded rods also serve as an attachment to wall.

For something heavy duty more than this, consider adding layers 6 & 7 as outlined above.

GOOD LUCK MY FRIEND,

Otis Guillebeau from Auburn, Georgia
This message was typed left-handed.


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## phillip.c (Aug 9, 2012)

Check this out:


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## Stick486 (Jan 4, 2013)

build the grid....
*DO NOT use MDF anyplace*...
I like the half bind joints...
incomplete grids like Rick's don't make it...
check for flatness. joints flushed and face/bottom parallel...
LA plane is the best too to fix any issues you have...
add your skins...
¼'' better plywood on the bottom is over kill...
PL construction adhesive beats the snot out of wood glue...


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## MT Stringer (Aug 15, 2012)

Have you checked out the You Tube videos produced by custom home builder Ron Paulk? You might get some inspiration from his stuff. Plans are available also.

I made a similar version for my miter saw setup.


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## Duane Bledsoe (Jan 6, 2013)

phillipdanbury said:


> Check this out:
> 
> https://www.youtube.com/watch?v=1-Hbsou6cWo


Interesting video. I will probably use some of those methods to make my box, but it will either be wood or plywood, not MDF. I love how while they're cutting the MDF, the one guy is masked up and has more breathing gear on than Darth Vader while the other guy has absolutely nothing and actually looks like he's mouth breathing. MDF = COPD down the road. I had one single experience with it, and it was BAD. Never seen so much dust in my life.


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## Herb Stoops (Aug 28, 2012)

IT should be MDC medium density cardboard.
Herb


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## Duane Bledsoe (Jan 6, 2013)

Stick486 said:


> build the grid....
> *DO NOT use MDF anyplace*...
> I like the half bind joints...
> incomplete grids like Rick's don't make it...
> ...


Oh yeah, I won't be using MDF. I have already noticed my new Kreg router table swells and contracts with humidity changes. It has a laminate on top and bottom, and around the edges. But sometimes the insert plate will feel a tiny bit recessed, and other times it feels flush, so I can tell it is going back and forth. The insert is phenolic, so it has to be the MDF table top. 

I would love to do half blind joints (thought those were called half lap). Man, it's gonna be a lot of work though. The video posted above just showed full length cross pieces connected by a series of shorter pieces. Is this not good enough? 

Also, how do you settle on what size openings to make when making the grid? My table will be a finished 48 x 68 inches, counting the edge band. Are 12 inch openings too wide?


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## Cherryville Chuck (Sep 28, 2010)

That should be fine.


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## Stick486 (Jan 4, 2013)

Oh yeah, I won't be using MDF. 
*there is a place for MDF...
left at the store or used on somebody else's project...*

I have already noticed my new Kreg router table swells and contracts with humidity changes. 
*and water and solvents and the drink condensation and......... *

It has a laminate on top and bottom, and around the edges. But sometimes the insert plate will feel a tiny bit recessed, and other times it feels flush, so I can tell it is going back and forth. The insert is phenolic, so it has to be the MDF table top.

I would love to do half blind joints 
*cake and pie...
even Rick did them... posted the pictures too..*

(thought those were called half lap).
*it could also be where you are standing in the world at the time as to what the they are called..
attached some pics...
these are half laps AIKI...
half blind are edge cut.. half lap are face cut... end to end is scarf...
*

Man, it's gonna be a lot of work though. 
*no...*

The video posted above just showed full length cross pieces connected by a series of shorter pieces. Is this not good enough?
*the cross joinery is way better and it shows...
same for wood glue vs PL construction adhesive...*

Also, how do you settle on what size openings to make when making the grid? My table will be a finished 48 x 68 inches, counting the edge band. Are 12 inch openings too wide?
*the higher the density within reason the stronger it is...
higher density squares get thinner material for the webs... weight/strength ratios..
you will be amazed at how strong a 6" torsion grid is using only 1¼'' lattice.. 4'' is off the scale so to speak..
for a one time forever quality build, S4S molding is outstanding.... 
S$S is generally thicker than lattice and starts at 5/16'' thicknesses... 1/2'' is wonderful stuff...
lattice starts out in 1/8''thickness and climbs in 1/16'' increments and stops at 7/16''...
Note... as it gets thicker it can very easily get wider...
s4s molding is generally better material over lattice even if it's the same species...*


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## jw2170 (Jan 24, 2008)

I have seen torsion boxes made large enough to be used as an assembly table. (8' x 4').....

Or the Paulk ? table. His uses deeper bracing as he stores tools underneath. Need not be that deep for a bench...


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## Herb Stoops (Aug 28, 2012)

jw2170 said:


> I have seen torsion boxes made large enough to be used as an assembly table. (8' x 4').....
> 
> Or the Paulk ? table. His uses deeper bracing as he stores tools underneath. Need not be that deep for a bench...


Ummmm,............Whats a Paulk, James?

Herb


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## jw2170 (Jan 24, 2008)

Ron Paulk has some videos on youtube about building his portable work bench.


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## RainMan 2.0 (May 6, 2014)

Stick486 said:


> build the grid....
> *DO NOT use MDF anyplace*...
> I like the half bind joints...
> incomplete grids like Rick's don't make it...
> ...


Do I know this Rick? :lol:


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## Duane Bledsoe (Jan 6, 2013)

Stick486 said:


> Oh yeah, I won't be using MDF.
> *there is a place for MDF...
> left at the store or used on somebody else's project...*
> 
> ...


Only problem with using s4s or lattice is finding some off the shelf that is still straight. Our Lowe's has all their trim stored in an upright position where it can settle, sag, and bow. Then people rifle through it looking for the best ones (guilty ), and leave them in a mess so the warping becomes worse and worse.

Thanks for all that info. It will really help. I do want this to be stupid strong, and last a very long time. It is going to be primarily an assembly/outfeed table, but I'd also like it if it could stand up to some hammer and chisel work as well. Nothing extreme. When I use a chisel, I tend to be light with it and just tap it. 

At this point I think I will be making the grid from something like 1/2" plywood with half lap joints, PL construction adhesive, and pocket hole screws to hold the edge band on. I will use a 3/4" pure bond plywood top, and a 1/4" lauan plywood bottom. Also, I will need an outer edge band of solid wood. Boy, I don't like the idea of using hardwood due to the overall cost, but nothing else seems like the answer so, we'll see. Seems like a high price just to decorate the outer edge, but I know it is sort of like armor for the edges as well. Soft pine and dimensional lumber would dent up easily, and also try to bow or warp, which may cause me trouble. 

I am also thinking a single 1/4" layer of hardboard for a replaceable top would be nice, and just screw it down, but I seem to recall reading somewhere that using screws in the surface would cause it to not be dead flat from the torque they put on the wood, making it bow, or draw in and hump up. Is there a way to do this right? I am thinking just countersink the screw heads and predrill everything.


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## Stick486 (Jan 4, 2013)

Thanks for all that info. It will really help. I do want this to be stupid strong, and last a very long time. It is going to be primarily an assembly/out feed table, but I'd also like it if it *could stand up to some hammer and chisel *work as well. Nothing extreme. When I use a chisel, I tend to be light with it and just tap it.
*
ummmmmmm...
what grid do you plan on using???...
might want to consider and apron/leg arrangement to transmit shock to the floor or go with a counter-brute force build...*

At this point I think I will be making the grid from something like *1/2" plywood with half lap joints*, PL construction adhesive, and pocket hole screws to hold the edge band on. 

*1/2 ply if it's Baltic or another high ply count plywood.....
glue 100% of the grid... *

I will use a 3/4" pure bond plywood top,
*
don't know pure bond...*

and a 1/4" luan plywood bottom. Also, *I will need an outer edge band of solid wood.*

*yes*

Boy, I don't like the idea of using hardwood due to the overall cost, *but nothing else seems like the answer so,

Huh???...* 

we'll see. Seems like a high price just to decorate the outer edge,

*it's not decorative.. it's structural...*

but I know it is sort of like armor for the edges as well. Soft pine and dimensional lumber would dent up easily, and also try to bow or warp, which may cause me trouble.

*QS closed cell would be very stable.... (fir, maple, etc) *

I am also thinking a single 1/4" layer of hardboard for a replaceable top would be nice, and just screw it down, but I seem to recall reading somewhere that using screws in the surface would cause it to not be dead flat 
from the torque they put on the wood, making it bow, or draw in and hump up. Is there a way to do this right? I am thinking just countersink the screw heads.

*segments of DS tape and a brass screw in each corner to pin it... nothing mare...
if you use tempered you'll be ahead of the game... *


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## Herb Stoops (Aug 28, 2012)

Duane if you install the edge piece 1/4" higher than the top the masonite will flush out with it One that I built ,I put an oak 2X2 on for an edge and raised it for the masonite and tacked the masonite every foot and a half with my brad gun so it would lay flat. If you screw it down, you will invariably hit the metal screws with your hand tools, chisels etc.
You are also going to want some solid blocking in the grid laid out for stops and bench dogs to hold down your work.

Herb


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## Cherryville Chuck (Sep 28, 2010)

Fir isn't that hard. Maple and red oak are much harder and wear resistant.Some pallets are made using poor grades of fairly hard wood but it would be hard to find something long enough without splicing it for the long sides. Equipment packing crates? Some of them would have longer pieces.

Use spray adhesive to put the HDF on with. Cover with a flat piece of ply or MDF (who says MDF has no uses) and add some weight until set up which is probably only 5 or 10 minutes. The edge banding will keep it from creeping, gravity and the adhesive will hold it down. It is possible to separate them if needed later but you might need to clean the old adhesive off to use the base layer again.


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## Duane Bledsoe (Jan 6, 2013)

Stick486 said:


> Thanks for all that info. It will really help. I do want this to be stupid strong, and last a very long time. It is going to be primarily an assembly/out feed table, but I'd also like it if it *could stand up to some hammer and chisel *work as well. Nothing extreme. When I use a chisel, I tend to be light with it and just tap it.
> *
> ummmmmmm...
> what grid do you plan on using???...
> ...


Ok, I will try to find tempered hardboard. My supply of materials here is limited. I know Home Depot carries 1/8 and 1/4 hardboard, but not sure if it's tempered or not. Nobody else here has it to my knowledge. 

As far as using baltic birch plywood, I'd love to. One dimesion of this table will make that hard though. The metal frame I have here measures 64 on the long side, and baltic birch is a maximum of 60 only. I can get 60 x 60 sheets of it here, but I will be 4 inches short of even reaching the full dimensions of the table frame, let alone the 2 inch overhang I was hoping to add all around for clamp use. I suppose I can do some doubled up glue ups of some kind to increase length on the longer grid pieces. That will add weight though, but maybe not as much as I think. 

Pure bond is a plywood that Home Depot sells that is void free inside. It doesn't have as many plies as baltic birch though. I was going to use it based on it being available in 4x8 sheets because I need a piece to cover the entire span of the grid for the top. 

You asked what grid I plan to use? I don't understand. Does that mean spacings or what? I was thinking of roughly 8 inch squares internally, something that would work out evenly one way, and close to even the other way. Maybe like 8 x 7.5 or something similar. On the apron and frame, I already have the metal Kreg bench frame. If you meant building it so my internal grid parts align with the apron of the stand, that is doable. I can lay it out that way. When I first read it, I thought you were suggesting I build one. I am past that point now. Have to use what I have, it is already assembled.


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## Duane Bledsoe (Jan 6, 2013)

Cherryville Chuck said:


> Fir isn't that hard. Maple and red oak are much harder and wear resistant.Some pallets are made using poor grades of fairly hard wood but it would be hard to find something long enough without splicing it for the long sides. Equipment packing crates? Some of them would have longer pieces.
> 
> Use spray adhesive to put the HDF on with. Cover with a flat piece of ply or MDF (who says MDF has no uses) and add some weight until set up which is probably only 5 or 10 minutes. The edge banding will keep it from creeping, gravity and the adhesive will hold it down. It is possible to separate them if needed later but you might need to clean the old adhesive off to use the base layer again.


How would I clean it without scraping, which may also remove some of the surface, making low spots in the otherwise flat surface? To me this seems like a lot of work and not worth the risk, but I may be overthinking it. I would prefer a much more hassle free top replacement procedure though. Something I could simply unscrew and remove, lay down a new sheet and screw it down again and be done. Anytime I build something for my use I try to also engineer easy maintenance into the design as well.


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## Duane Bledsoe (Jan 6, 2013)

Herb Stoops said:


> Duane if you install the edge piece 1/4" higher than the top the masonite will flush out with it One that I built ,I put an oak 2X2 on for an edge and raised it for the masonite and tacked the masonite every foot and a half with my brad gun so it would lay flat. If you screw it down, you will invariably hit the metal screws with your hand tools, chisels etc.
> You are also going to want some solid blocking in the grid laid out for stops and bench dogs to hold down your work.
> 
> Herb


If I screw it like Stick suggested, one per corner, I think they would be out of the way enough. Thats only 4 screws in the whole sheet. 

On bench dogs, I don't use them. My Harbor Freight benches have them and I tried them and didn't like them. I know other woodworkers use them with success. I primarily work with pine lumber, which is soft, and I found that the dog inserts dented it up when used to clamp a part in place, so I use bar clamps, a rubberized surface mat to prevent sliding of wood while I work it, and other methods to immobilize my work pieces.


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## Duane Bledsoe (Jan 6, 2013)

It seems there may be a lot of bad info on the internet (what a surprise!) about torsion boxes. I read an old thread on another forum where someone said the half lap joints in the grid could even be sloppy and it would still be ok. To a point I can see that with all the ribs going in both directions, and having plywood nailed on on both sides, it would remain somewhat rigid, but I figure the joints will help counter any tendency of the internal ribs to twist or bow, but if they are sloppy then there is less resistance if one or more of the internal ribs begins to bow. . 

Also, I read that a grid can be made with only full length ribs in one direction, and just shorter fill in pieces for the perpendicular ribs. Again, this is obviously not as strong as having all of them full length and half lapped snuggly, but if they are fastened securely, nailed and glued, will it be good enough? 

The reason I ask is because I would like to make the grid from baltic birch. I figure I'll do it once and then it will last from now on, and baltic birch is the most stable wood I can think of to use. However, the largest and longest length I can find it in is 60 x 60 inch sheets. My grid is longer than that in one direction, up to 68 inches, but if I made that direction the one with the filler pieces then I can do the whole grid from the birch plywood. 

I'd like to even make the top 3/4" sheet from baltic birch but it isn't long enough to do it without a seam, which I think is not supposed to be done with a torsion box. Yay or nay?


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## Stick486 (Jan 4, 2013)

It seems there may be a lot of bad info on the internet (what a surprise!) about torsion boxes. 
*I'm in luck... haven't read much of it...
what do you consider to be the bad information???...*

I read an old thread on another forum where someone said the half lap joints in the grid could even be sloppy and it would still be ok. 
*unless you use an adhesive that can bridge gaps they don't work out so well.. PL does this well...
*
To a point I can see that with all the ribs going in both directions, and having plywood nailed on on both sides, 
*nails don't work out so well in the long run....
screws do though.. countersunk on the top and K-Lath type on the bottom for 1st choice and pocket hole for a distant 2nd...
NOTE: if the pocket hole screw is sunk too deep into the top bulges will form at the screw locations...
*
it would remain somewhat rigid, but I figure the joints will help counter any tendency of the internal ribs to twist or bow, but if they are sloppy then there is less resistance if one or more of the internal ribs begins to bow. .
*correct...
*
Also, I read that a grid can be made with only full length ribs in one direction, and just shorter fill in pieces for the perpendicular ribs. 
Again, this is obviously not as strong as having all of them full length and half lapped snugly,
*correct...
*
but if they are fastened securely, nailed and glued, will it be good enough?
*no... stresses over time will show... this is a short coming of regular wood glues and butt joints....
of all the joints you can make a butt joint is the weakest even w/ glue and mechanical fasteners...*

The reason I ask is because I would like to make the grid from Baltic birch.
*okay...
*
I figure I'll do it once and then it will last from now on, 
*makes sense...
*
and Baltic birch is the most stable wood I can think of to use.
*agreed..
*
However, the largest and longest length I can find it in is 60 x 60 inch sheets. My grid is longer than that in one direction, up to 68 inches,
*make a scarf joint between perpendicular ribs and plate the joint
stagger/offset the joints from one another... avoid having them in line...
*
but if I made that direction the one with the filler pieces then I can do the whole grid from the birch plywood.
*not sure what you are saying*

I'd like to even make the top 3/4" sheet from Baltic birch but it isn't long enough to do it without a seam, 
*so... spline on what you need...
*
which I think is not supposed to be done with a torsion box. Yay or nay?
*I've never had an issue w/ it...
now for the bottom ¼'' ply make the seam fall on cat blocks that are installed flat......
it only need to be blocking and not an additional mortised in rib but there's nothing stopping you from doing it...
I would because I'm anallitic that way...*


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## Herb Stoops (Aug 28, 2012)

Duane see if a lumber yard near by sells Russian Birch. It is very similar to Baltic birch and comes in 4X8 sheets. It has as many plys but the core sheets are not quite as clear as Baltic birch. I did see baltic birch in4X8 sheets one time at a hardwood supplier, before it started to get scarce. Seems as China is buying it all up. 

Herb


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## Stick486 (Jan 4, 2013)

Appleply is another choice and competes w/ Baltic birch...


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## Herb Stoops (Aug 28, 2012)

Stick486 said:


> Appleply is another choice and competes w/ Baltic birch...


Yep, forgot about the Ole Appleply, ( not made from apple wood), it is mighty fine stuff.

we used to make concrete forms with Finn Ply it had a red resin type coating on it and beautiful face along with a jillian plys. It was when we poured architectural concrete walls.

Herb


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## Stick486 (Jan 4, 2013)

Herb Stoops said:


> Yep, forgot about the Ole Appleply, ( not made from apple wood), it is mighty fine stuff.
> 
> we used to make concrete forms with Finn Ply it had a red resin type coating on it and beautiful face along with a jillian plys. It was when we poured architectural concrete walls.
> 
> Herb


AA or AB fir could be another choice...

we knew that as NorForm Fir...


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## Duane Bledsoe (Jan 6, 2013)

When using a hardboard top and securing with double sided tape, is there any risk to the hardboard dipping in between the tape strips from pressure applied above? It seems a large amount of surface area between the top layer and supporting layer below won't make contact from tape thickness separating them and might create a slightly wavy surface.

Would a screw in each corner be enough by themselves? Will the hardboard lay flat in this case?

If not, then I suppose several screws through the middle area will work, but then there's the problem of replacement later and drilling a dozen matching holes exactly in line with the old ones, or else making new ones and slowly turning the sub layer into swiss cheese over time.

Also, as I build it, I'd like to size the frame so that when replacing the top layer all I'd need to do is cross cut the new sheet for total length and then lay it in. Does hardboard come in consistant widths and lengths or will there be any danger of me having to cut it both ways in order to fit each time? I may be overthinking that part. Looks like a pattern bit in a router would fix that. Didn't come to mind right away since I have yet to ever use one. What about thickness consistency?


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## Gaffboat (Mar 11, 2012)

Duane Bledsoe said:


> When using a hardboard top and securing with double sided tape, is there any risk to the hardboard dipping in between the tape strips from pressure applied above? It seems a large amount of surface area between the top layer and supporting layer below won't make contact from tape thickness separating them and might create a slightly wavy surface.
> 
> Also, as I build it, I'd like to size the frame so that when replacing the top layer all I'd need to do is cross cut the new sheet for total length and then lay it in. Does hardboard come in consistant widths and lengths or will there be any danger of me having to cut it both ways in order to fit each time? I may be overthinking that part. Looks like a pattern bit in a router would fix that. Didn't come to mind right away since I have yet to ever use one. What about thickness consistency?


You may be overthinking this project, Duane. I believe you said this was to be an assembly / outfeed table. My double-sided tape measures about .0065" thick which is less than 1/128th of an inch. Surely that's flat enough for any woodworking project.

Tempered masonite (hardboard) is tougher than you think. When I built my workbench I put 1/4" masonite on the top. I only screwed it in place so I could change it out when needed. That was 35 years ago and I haven't changed it yet. I occasionally use a chisel to scrape off glue drips but it has withstood a lot of abuse.

By the time you get around to needing to change the top of your table there will probably be some kind of kevlar / carbon fiber / graphene material available for your next table that will be super strong and weigh next to nothing. :grin:


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## Stick486 (Jan 4, 2013)

Gaffboat said:


> You may be over thinking this project, . :grin:


agreed...


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## Herb Stoops (Aug 28, 2012)

Duane get some thin DB tape,not the foam stuff. They sell tape that is like scotch tape W/adhesive on both sides. If the surface is clean, It sticks like a suction cup. 
Masonite comes in 4X8 sheets, you will have to cut it both directions. If there is a little crack along the edge, it wont hurt and will fill with sawdust eventually.

Haven't heard you say anything about backing for your vise.
Herb


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## Duane Bledsoe (Jan 6, 2013)

Herb Stoops said:


> Duane get some thin DB tape,not the foam stuff. They sell tape that is like scotch tape W/adhesive on both sides. If the surface is clean, It sticks like a suction cup.
> Masonite comes in 4X8 sheets, you will have to cut it both directions. If there is a little crack along the edge, it wont hurt and will fill with sawdust eventually.
> 
> Haven't heard you say anything about backing for your vise.
> Herb


Uuuuuuhh......vise???.............

Hmm. Maybe I should add one. I have three of the Harbor Freight benches that I am actually just using for counters now and the way they back up against each other, and into a corner, I have removed every single one of the tail vises. I could scab the hardware from those and incorporate it into the bench top I am making. Would that be a good idea, or is there something else I should do instead? Keep in mind, I do have a budget, the sky is not the limit, however, today I did spend another $350 at the woodworking store I have discovered here recently. Details in my new torsion box build thread I'm about to start.


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